2--hydroxy-5-9-dimethyl-2-allyl-6-7-benzomorphan and preclamol

We evaluated the effects of phenytoin (DPH) on the affinity for sigma-1 (sigma(1)) receptors of agonist or antagonist sigma(1) ligands in guinea pig brain. Heterologous competition experiments showed that DPH (250 microM and 1 mM) concentration-dependently increased the affinity of the sigma(1) agonists dextromethorphan, (+)-SKF-10,047, (+)-3-PPP, and PRE-084. However, neither DPH 250 microM nor 1 mM increased (in fact, they slightly decreased) the affinity of the sigma(1) receptor antagonists haloperidol, BD 1063, NE-100, progesterone, and BD 1047. These findings suggest that allosteric modulation by DPH of the affinity of sigma(1) receptor ligands depends on the agonist or antagonist characteristics of the ligand. Therefore, determining in vitro the differential modulation by DPH of sigma(1) ligand affinity appears to constitute a procedure that can predict the pharmacological profile of different sigma(1) ligands.

Topics: Allosteric Regulation; Animals; Anisoles; Anticonvulsants; Binding, Competitive; Brain; Dextromethorphan; Drug Interactions; Ethylenediamines; Guinea Pigs; Haloperidol; Ligands; Male; Morpholines; Neurons; Phenazocine; Phenytoin; Piperazines; Piperidines; Progesterone; Propylamines; Receptors, sigma; Synaptic Transmission

We investigated the effects of sigma receptor ligands on neuronal death induced by chemical ischemia using primary cultures of rat cerebral cortical neurons. The induction of chemical ischemia by sodium azide and 2-deoxy-D-glucose led to delayed neuronal death in a time- and concentration-dependent manner, as determined by trypan blue exclusion. The neurotoxicity was inhibited by N-methyl-D-aspartate (NMDA) receptor antagonists, indicating the involvement of glutamate. The sigma receptor ligands (+)-N-allylnormetazocine ((+)-SKF10,047) and haloperidol, but not carbetapentane and R(+)-3-(3-hydroxyphenyl)-N-propylpiperidine ((+)-3-PPP), prevented chemical ischemia-induced neurotoxicity in a concentration-dependent manner. The protective effects of (+)-SKF10,047 and haloperidol were not affected by the sigma receptor antagonists. (+)-SKF10,047 and haloperidol, but not carbetapentane and (+)-3PPP, inhibited the glutamate-induced increase in intracellular Ca(2+), and the inhibitory effects were not attenuated by sigma receptor antagonists. These results suggest that direct interaction with NMDA receptors but not sigma receptors is crucial to the neuroprotective effects of sigma receptor ligands with affinity for NMDA receptors.

Topics: 2-Amino-5-phosphonovalerate; Animals; Calcium; Cell Hypoxia; Cell Survival; Cells, Cultured; Cerebral Cortex; Cyclopentanes; Deoxyglucose; Dizocilpine Maleate; Dose-Response Relationship, Drug; Excitatory Amino Acid Antagonists; Fetus; Glucose; Glutamates; Haloperidol; Neurons; Phenazocine; Piperidines; Rats; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Receptors, sigma; Sodium Azide

The effects of trazodone and putative sigma (sigma) receptor ligands were investigated on KCl-stimulated release of glutamate (Glu) and gamma-aminobutyric acid (GABA) from cerebellar mossy fibre synaptosomes. Both trazodone and serotonin (5-HT) inhibited the increase of Glu and GABA release evoked by 15 mM KCl. Trazodone increased the inhibition of Glu release caused by 0.01 microM 5-HT, while it antagonized the inhibition induced by higher 5-HT concentrations. Despite the low affinity of trazodone for both sigma(1) and sigma(2) binding sites, with a pK(i) of 5.9 and 6.0 respectively, two sigma receptor ligands, (+)-3-[3-hydroxypheny]-N-(1-propyl)piperidine ((+)-3-PPP) and N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine (BD 1047) antagonized the effects of trazodone. The putative sigma receptor ligand N-allylnormetazocine ((+)-SKF 10,047) mimicked the inhibitory effect of trazodone. As with trazodone, (+)-3-PPP and BD 1047 antagonized the activity of (+)-SKF 10,047 but not that of 5-HT. On the whole, these results suggest that trazodone shares a common molecular target with sigma compounds distinct from that of 5-HT and is involved in K(+)-stimulated Glu and GABA release from mossy fibre cerebellar synaptosomes.

Topics: Animals; Antidepressive Agents, Second-Generation; Cerebellum; Ethylenediamines; gamma-Aminobutyric Acid; Glutamic Acid; Male; Nerve Fibers; Phenazocine; Piperidines; Potassium Chloride; Rats; Rats, Sprague-Dawley; Receptors, sigma; Serotonin; Synaptosomes; Trazodone

Intraperitoneal administration of 4-cyclohexyl-1-[(1R)-1,2-diphenylethyl]-piperazine (CDEP) immediately after the training session produced significant memory impairment in the mouse passive avoidance performance. Interestingly, this memory impairment was alleviated by subcutaneous administrations of sigma receptor agonists, (+)-N-allylnormetazocine ((+)-SKF-10,047), (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) and 1,3-di(2-tolyl)guanidine (DTG) immediately after the training session. In particular, the remarked recovery for this memory impairment was produced by (+)-SKF-10,047. A receptor binding study showed that CDEP possessed high affinities for both sigma 1 and sigma 2 receptor subtypes (IC50 1.4 +/- 0.3 nM for sigma 1 receptor subtype, 1.8 +/- 0.3 nM for sigma 2 receptor subtype), while (+)-SKF-10,047 had a high selectivity for the sigma 1 receptor subtype. These findings suggest that the sigma receptor, particularly sigma 1 receptor subtype, may play an important role in the CDEP-induced impairment of learning and memory processes.

Topics: Animals; Antipsychotic Agents; Avoidance Learning; Binding, Competitive; Brain Chemistry; Dopamine Agonists; Guinea Pigs; Male; Membranes; Memory Disorders; Mice; Phenazocine; Piperazines; Piperidines; Radioligand Assay; Receptors, sigma

In vitro receptor autoradiography was used to localize sigma 1 receptors, sigma 2 receptors, and novel haloperidol/DTG-inaccessible sites for sigma and opiate ligands in rat spleen. Sigma-1 receptors were present throughout the spleen, but were most concentrated in the T cell zones. Binding under "sigma 2 receptor-selective' conditions was 70% nonspecific, and sigma 2 receptors could not be detected. Haloperidol/DTG-inaccessible sites had a coarse, punctate distribution in the red pulp and marginal zones of the white pulp. This anatomical localization suggests types of cells and functions that should be examined for modulation by sigma receptors.

Topics: Analgesics, Opioid; Animals; Anticonvulsants; Antipsychotic Agents; Autoradiography; Binding Sites; Dopamine Agonists; Dopamine Antagonists; Female; Guanidines; Haloperidol; Image Processing, Computer-Assisted; Ligands; Male; Naltrexone; Narcotic Antagonists; Pentazocine; Phenazocine; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, sigma; Spleen; Tritium

We examined the ameliorating effects of several sigma receptor agonists on scopolamine-induced memory impairment in mice. Scopolamine was administered IP 30 min before the training session. Each sigma receptor agonist was administered 60 min before or immediately after the training session, or 60 min before the retention test in the passive-avoidance performance experiments. (+)-N-Allylnormetazocine ((+)-SKF-10,047), a prototype sigma 1 receptor agonist, showed an ameliorating effect on the scopolamine-induced memory impairment in these 3 administration schedules, and (-)-SKF-10,047, a stereoisomer with low affinity for the sigma 1 receptor subtype, failed to reduce this memory impairment in mice. In addition, 1,3-di(2-toly1)guanidine (DTG) and (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperizine ((+)-3-PPP), nonselective sigma receptor agonists, did not affect this memory impairment. Physostigmine, an acetylcholinesterase (AChE) inhibitor, alleviated the scopolamine-induced memory impairment in all these drug administration schedules. In addition, (+)-SKF-10,047-induced antiamnesic effect was antagonized by the concurrent administration of haloperidol, a sigma receptor antagonist, or N,N-dipropyl-2-(4-methoxy-3-(2-phenylethoxy) phenyl)ethylamine monohydrochloride (NE-100), a selective sigma 1 receptor antagonist. These findings indicate that the sigma 1 receptor agonist has ameliorating effects on all phases of learning and memory processes. This profile of sigma 1 receptor agonist is similar to that of an AChE inhibitor.

Topics: Acetylcholinesterase; Animals; Antipsychotic Agents; Avoidance Learning; Brain; Dose-Response Relationship, Drug; Guanidines; Male; Mental Recall; Mice; Mice, Inbred Strains; Phenazocine; Piperidines; Receptors, sigma; Scopolamine

The effects of sigma-receptor ligands on the twitch contraction elicited by the exogenous application of adenosine 5'-triphosphate (ATP) in the unstimulated mouse vas deferens were studied. (-)-Pentazocine, 1,3-di(2-tolyl)guanidine(DTG) and two pairs of optical isomers of 3-(3-hydroxyphenyl)-N-(1-propyl)piperidine(3-PPP) and N-allylnormetazocine (SKF-10,047) potentiated the exogenous application of ATP-induced twitch-type contraction in a concentration-dependent manner, while (+)-pentazocine did not affect it. The order of potentiating ability was: (+)-3-PPP > (-)pentazocine > (-)-SKF-10,047> DTG > (-)-3-PPP > (+)-SKF-10,047. On the other hand, haloperidol and rimcazole, putataive sigma-receptor antagonists, suppressed this twitch contraction. In addition, these antagonists significantly blocked the (+)-3-PPP- and (-)-pentazocine-induced potentiation at concentrations which did not affect contractions per se. These findings indicate that the exogenous application of ATP-induced twitch contraction in the mouse vas deferens is regulated by sigma-receptors. In addition, the present ranking order suggests that the sigma-receptor potentiating the ATP-induced twitch contraction at post-junctional sites may differ from the sigma 1- and/or sigma 2-receptor subtypes.

Topics: Adenosine Triphosphate; Analgesics, Opioid; Animals; Anticonvulsants; Antipsychotic Agents; Carbazoles; Dopamine Agonists; Dopamine Antagonists; Dose-Response Relationship, Drug; Drug Synergism; Guanidines; Haloperidol; Ligands; Male; Mice; Muscle Contraction; Muscle, Smooth; Pentazocine; Phenazocine; Piperidines; Receptors, sigma; Regression Analysis; Structure-Activity Relationship; Vas Deferens

To investigate the in vivo functional interaction between phencyclidine (1-(1-phenylcyclohexyl)piperidine; PCP) binding sites and sigma receptors, we examined the effects of sigma receptor ligands on stereotyped head-weaving behavior induced by PCP, a putative PCP/sigma receptor ligand, and (+)-5-methyl-10,11-dihydroxy-5H-dibenzo(a,d)cyclo-hepten-5,10-imin e ((+)-MK-801; dizocilpine), a selective PCP binding site ligand, in rats. PCP (7.5 mg/kg, i.p.)-induced head-weaving behavior was inhibited by both N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)-phenyl]-ethylamine (NE-100; 0.03-1.0 mg/kg, p.o.), a selective sigma1 receptor ligand, and alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperidine butanol (BMY-14802; 3 and 10 mg/kg, p.o.), a prototype sigma receptor ligand, in a dose-dependent manner, whereas NE-100 (0.1-1.0 mg/kg, p.o.) and BMY-14802 (3 and 10 mg/kg, p.o.) did not inhibit dizocilpine (0.25 mg/kg, s.c.)-induced head-weaving behavior. These results suggest that NE-100 and BMY-14802 act via sigma receptors. Dizocilpine-induced head-weaving behavior was potentiated by 1,3-di-o-tolyl-guanidine (DTG; 0.03-0.3 microg/kg, i.v.) and (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP; 3 and 6 mg/kg, i.p.), sigma1/sigma2 receptor ligands, as well as by (+)-N-allyl-normetazocine ((+)-SKF-10,047: 8 mg/kg, i.p.), a sigma1 receptor ligand, while DTG (0.3 microg/kg, i.v.), (+)-3-PPP (6 mg/kg, i.p.) and (+)-SKF-10,047 (8 mg/kg, i.p.) did not induce this behavior. Potentiation of dizocilpine-induced head-weaving behavior by DTG (0.3 microg/kg, i.v.), (+)-3-PPP (6 mg/kg, i.p.) and (+)-SKF-10,047 (8 mg/kg, i.p.) was completely blocked by NE-100 (0.1 mg/kg, p.o.) and BMY-14802 (10 mg/kg, p.o.). These results suggest that PCP binding sites and sigma receptors are involved in PCP-induced head weaving behavior, and that sigma1 receptors play an important role in modulation of the head-weaving behavior.

Topics: Animals; Anisoles; Behavior, Animal; Binding Sites; Dizocilpine Maleate; Guanidines; Male; Phenazocine; Piperidines; Propylamines; Pyrimidines; Rats; Rats, Wistar; Receptors, Phencyclidine; Receptors, sigma

The sigma receptor/binding site, found in the brain and periphery, binds haloperidol, (+)-benzomorphans, N-propyl-3-(3-hydroxyphenyl)-piperidine (3-PPP) and certain atypical neuroleptics with high affinity. We have succeeded in ca. 6,000-fold purification of protein(s) from rat and bovine cerebellum which display pharmacology characteristic of the sigma receptor. This purification was achieved by affinity chromatography using a Sepharose gel linked to a new high-affinity ligand, (S)-3-(3-methoxyphenyl)-3'-oxo-3'-phenyl-N-propylpiperidine, an analog of (S)-3-PPP. Elution of the affinity column with haloperidol afforded material which, after reconstitution into bimolecular lipid vesicles, was pharmacologically characterized by specific radioligand binding assays using [3H]haloperidol combined with competitive displacement using appropriate selective ligands. Comparison of the relative rank orders of potency of the ligands in these selective sigma receptor assays corresponded well with values obtained with tissue homogenates. The observed enantioselectivity for the binding of SKF-10,047 and cyclazocine suggests that the material purified corresponds to the sigma 1 receptor subtype. SDS-PAGE indicated that the purified material consisted of two bands of approximate molecular masses 65 and 63 kilodaltons. Photoaffinity labeling of the affinity-purified receptor with [3H]azido-DTG led to incorporation of the label into material of molecular mass 50-70 kDa, by slicing of SDS gels, while similar photolabeling of crude cerebellar homogenates led to exclusive labeling of a 29 kDa polypeptide, as found previously using other tissues. Molecular sizing under non-denaturing conditions indicated the photolabeled species is a labile large receptor complex of mass ca. 300-500 kDa which gradually breaks down upon standing at -80 degrees C into the lower mass (50-70 kDa) material. The sigma receptor ligand binding subunit, which appears to be of the sigma 1 subtype, appears to be contained within the 29 kDa polypeptide, which may be a subunit of the 63-65 kDa protein, which in turn appears to be a component of a much larger receptor complex. It further appears that the 29 kDa polypeptide is readily dissociable from a larger photolabeled sigma receptor complex in tissue homogenates, but does not dissociate from the photolabeled affinity-purified CHAPS-solubilized sigma receptor.

Topics: Animals; Binding Sites; Cattle; Cerebellum; Dopamine Agonists; Haloperidol; Male; Phenazocine; Piperidines; Rats; Receptors, sigma

The role of the putative sigma receptor in mediating neuroprotection against glutamate-induced neuronal injury was examined in mature cultured rat cortical neurons. With the exception of the selective sigma 1 ligand (+)-3-PPP, all of the sigma ligands tested were neuroprotective, preventing glutamate-induced morphological changes and increases in LDH release. Their rank order of neuroprotective potency (and EC50 values) was as follows: (+)-SKF 10,047 (0.81 microM) > (+)- cyclazocine (2.3 microM) > dextromethorphan (3.1 microM) = haloperidol (3.7 microM) > (+)-pentazocine (8.5 microM) > DTG (42.7 microM) = carbetapentane (46.3 microM). When corrected for relative sigma versus PCP binding affinity, it appears that a positive correlation exists between neuroprotective potency and sigma 1 site affinity. However, there does not appear to be a significant correlation between neuroprotective potency and the sigma 2 site. Critically, none of the sigma ligands were neurotoxic when tested alone at concentrations at least 5-30 times their respective neuroprotective EC50 values. Results from preliminary experiments with the selective sigma 1 ligand (+)-pentazocine indicated that sigma-mediated neuroprotection may involve the buffering of glutamate-induced calcium flux. Collectively, the results of these in vitro experiments demonstrate that sigma ligands are neuroprotective and therefore deserve further exploration as potential therapeutic agents in in vivo models of CNS injury and neurodegenerative disorders.

Topics: Animals; Calcium; Cells, Cultured; Cyclazocine; Cyclopentanes; Dextromethorphan; Glutamic Acid; Guanidines; Haloperidol; L-Lactate Dehydrogenase; Neurons; Neuroprotective Agents; Pentazocine; Phenazocine; Piperidines; Rats; Receptors, sigma

Acute administration of (+)-N-allylnormetazocine ((+)-SKF-10,047) and (+/-)-pentazocine, was found to increase the extracellular level of 3,4-dihydroxyphenylacetic acid (DOPAC), a major dopamine (DA) metabolite, in the rat frontal cortex. By contrast, these benzomorphan sigma ligands did not change the extracellular DOPAC level in the rat striatum. On the other hand, 1,3-di(2-tolyl)guanidine (DTG) increased the extracellular DOPAC level in the frontal cortex, while it decreased that level in the striatum. Another non-benzomorphan sigma ligand, (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) decreased the extracellular DOPAC level in both frontal cortex and striatum. Moreover, the increase of the extracellular DOPAC level elicited by (+)-SKF-10,047 was significantly inhibited by rimcazole, a putative sigma antagonist, while the DTG-induced increment was not reversed by rimcazole. These findings indicated that the effects of sigma ligands on the mesocortical DA neurons differed from those on the nigrostriatal DA neurons. In addition, the effects of benzomorphan sigma ligands on the central DA neurons were different from those of non-benzomorphan sigma ligands.

Topics: 3,4-Dihydroxyphenylacetic Acid; Animals; Anticonvulsants; Antipsychotic Agents; Carbazoles; Corpus Striatum; Extracellular Space; Frontal Lobe; Guanidines; Kinetics; Ligands; Male; Microdialysis; Pentazocine; Phenazocine; Piperidines; Rats; Rats, Wistar; Receptors, sigma; Time Factors

In preparation for expression studies for rat brain sigma-binding sites, Xenopus oocytes were tested for the presence of [3H]di-o-tolylguanidine (DTG)-binding sites. Native oocytes were found to contain two intrinsic [3H]DTG-binding sites, a high-affinity site (Kd = 32 +/- 6 nM, Bmax of 45.7 +/- 19 pmol/mg protein) and a low-affinity binding site (Kd = 1.3 +/- 0.7 microM, Bmax of 3.2 +/- 0.7 nmol/mg protein). In a series of radioligand-binding-displacement studies, the high-affinity binding sites were found to have a binding profile which has a similar Kd to that of the mammalian sigma 2-binding site (32 vs. 38 nM). Comparison of the IC50 values for inhibition of [3H]DTG binding in rat liver and oocytes for DTG, haloperidol (HAL), (-)-pentazocine, (+)-3-(3-hydroxyphenyl)-N-propylpiperidine hydrochloride ((+)-3-PPP), (+)-pentazocine and Zn2+, showed similarity in rank (r2 = 0.913) but a 7-fold lower potency in oocytes. These results suggest that the high-affinity [3H]DTG-binding site in oocytes represents a sigma 2-like binding site.

Topics: Animals; Binding Sites; Binding, Competitive; Carbazoles; Dextromethorphan; Female; Guanidines; Haloperidol; Liver; Mazindol; Oocytes; Pentazocine; Phenazocine; Piperazines; Piperidines; Radioligand Assay; Rats; Receptors, sigma; Xenopus laevis; Zinc

Three sigma receptor ligands were examined for their ameliorating effects on p-chloroamphetamine-induced amnesia in mice. p-Chloroamphetamine was administered intraperitoneally 30 min before the training session of the passive avoidance response. Each sigma receptor ligand was administered 60 min before or immediately after the training session, or 60 min before the retention test. (+)-N-Allylnormetazocine ((+)-SKF-10,047), a prototype benzomorphan sigma receptor ligand, significantly reduced the p-chloroamphetamine-induced amnesia in these three administration schedules, as do acetylcholinesterase inhibitors. On the contrary, the significant anti-amnesic effects elicited by non-benzomorphan sigma receptor ligands, 1,3-di-(2-tolyl)guanidine (DTG) or (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperizine ((+)-3-PPP), were observed depending upon the timing of their administration. In addition, the ameliorating effect of (+)-SKF-10,047 against the p-chloroamphetamine-induced amnesia was superior to that of (-)-SKF-10,047. The (+)-SKF-10,047-induced anti-amnesic effect was significantly antagonized by the concurrent administration of either scopolamine, a muscarinic receptor antagonist, or hemicholinium-3, an inhibitor of the Na(+)-dependent high-affinity choline uptake site. These findings indicated that sigma receptor ligands had anti-amnesic effects against drug-induced memory impairment. In addition, the anti-amnesic effect of (+)-SKF-10,047 was superior to those of other sigma receptor ligands, and was mediated by both the sigma receptor and the central acetylcholinergic system.

Topics: Acetylcholine; Amnesia; Animals; Anticonvulsants; Avoidance Learning; Brain; Cholinesterase Inhibitors; Dopamine Agonists; Electroshock; Guanidines; Ligands; Male; Memory; Mice; Mice, Inbred Strains; p-Chloroamphetamine; Phenazocine; Piperidines; Receptors, sigma; Serotonin Antagonists

We examined the characteristics of the binding of radiolabeled 5,8-dimethyl-4-(2-di-n-propylaminoethyl)carbazol monohydrochloride ([3H]FH-510), a highly potent and selective sigma ligand, to guinea-pig brain membranes. [3H]FH-510 showed saturable and reversible binding to sigma binding sites. The association rate constant (k+1) and dissociation rate constant (k-1) of [3H]FH-510 were 0.023 min-1.nM-1 and 0.081 min-1, respectively. Scatchard plot analysis showed a dissociation constant (Kd) and maximal number of binding sites (Bmax) of 6.0 +/- 0.63 nM and 1763.3 +/- 177.4 fmol/mg protein (n = 7), respectively. The rank order of potency (Ki) of several structurally dissimilar sigma ligands obtained for the displacement of [3H]FH-510 binding was highly correlated with that determined for [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ([3H](+)-3-PPP) binding. The binding of [3H]FH-510 was not influenced by histaminergic, dopaminergic, adrenergic, serotonergic or cholinergic agents at 10(-7) M. Higher [3H]FH-510 binding to brain regions was observed in the cerebellum and pons-plus-medulla. Except for the nuclear fraction, the highest level of [3H]FH-510 and [3H](+)-3-PPP binding to subcellular fractions was observed in the microsomal fraction. From these results, it is suggested that FH-510 selectively binds with high affinity to sigma binding sites in guinea-pig membranes.

Topics: Animals; Anti-Anxiety Agents; Binding Sites; Binding, Competitive; Brain; Carbazoles; Dopamine Agents; Guinea Pigs; Histamine; In Vitro Techniques; Kinetics; Male; Microsomes; Phenazocine; Piperidines; Propylamines; Pyrimidines; Radioligand Assay; Receptors, sigma; Serotonin

The effects of sigma receptor ligands on the neurogenic twitch contraction in the ddY mouse vas deferens were studied. In functional studies, (+)-N-allylnormetazocine ((+)-SKF-10,047) and (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) potentiated neurogenic twitch contractions in a concentration-dependent manner. The potentiation by each (+) enantiomer was significantly more potent than that by the respective (-) enantiomer. In addition, haloperidol and (+/-)-pentazocine also potentiated neurogenic twitch contractions. The order of potentiating ability was: haloperidol > (+/-)-pentazocine > (+)-3-PPP > (-)-3-PPP > (+)-SKF-10,047 > (-)-SKF-10,047. In contrast, other sigma receptor ligands, 1,3-di(2-tolyl)guanidine (DTG) and rimcazole, suppressed this twitch contraction. In addition, rimcazole significantly antagonized the (+)-SKF-10,047-induced potentiation at concentrations which did not affect contractions per se. Furthermore, binding studies showed that the kinetic parameters and the inhibitory potencies of sigma receptor ligands for the binding of [3H](+)-SKF-10,047 in the mouse vas deferens were similar to those in the guinea pig brain. The order of potency of sigma receptor ligands to potentiate the neurogenic twitch contraction in the mouse vas deferens was significantly correlated with the potency to inhibit [3H](+)-SKF-10,047 binding in both mouse vas deferens and guinea pig brain. These results indicate that sigma receptor ligands regulate the neurogenic twitch contraction, which is mediated by rimcazole-sensitive benzomorphan-type sigma receptors.

Topics: Animals; Antiparkinson Agents; Brain; Drug Synergism; Guinea Pigs; Haloperidol; Ligands; Male; Mice; Phenazocine; Piperidines; Receptors, sigma; Spasm; Vas Deferens

The allosteric modulation of sigma recognition sites by phenytoin (diphenylhydantoin) has been demonstrated by the ability of phenytoin to stimulate binding of various [3H] sigma ligands, as well as to slow dissociation from sigma sites and to shift sigma sites from a low- to a high-affinity state. Phenytoin stimulated the binding of the sigma 1- selective ligand [3H](+)pentazocine in a dose-dependent manner. Stimulation of binding at a final concentration of 250 microM phenytoin was associated with a decrease in the KD. The affinities of the sigma reference compounds caramiphen, dextromethorphan, dextrophan, (+)3-PPP and (+)SKF-10,047 were three- to eight-fold higher, while the affinities of benzetimide, BMY-14802, carbetapentane, DTG and haloperidol were unchanged in the presence of 250 microM phenytoin. The relative sensitivity of sigma compounds to allosteric modulation by phenytoin is not a property of all sigma ligands, and may provide an in vitro basis for distinguishing actions of sigma compounds and predicting sigma effects in vivo.

Topics: Allosteric Regulation; Animals; Binding Sites; Cyclopentanes; Dextromethorphan; Dextrorphan; Guinea Pigs; Ligands; Male; Pentazocine; Phenazocine; Phenytoin; Piperidines; Radioligand Assay; Receptors, sigma; Tritium

High-affinity binding sites (apparent KD 2.87 nM) for [3H]desmethylimipramine ([3H]DMI), have been demonstrated and characterized in membrane preparations of bovine adrenal medulla. The binding of [3H]DMI improved upon pretreatment of the membrane with KCl and was saturable, sodium dependent, and potently inhibited by nisoxetine and imipramine. [3H]DMI binding was also inhibited by various phencyclidine (PCP)- and (or) sigma-receptor ligands, with the following order of potency: haloperidol > rimcazole > (-)-butaclamol > dextromethorphan > MK-801 > (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) > PCP > N-(2-thienyl)cyclohexyl-3,4-piperidine (TCP) > (+)-SKF-10047 > (-)-SKF-10047. The inhibition produced by sigma ligands was not attributed to stimulation of either sigma 1- or sigma 2-receptors, owing to inactivity of the selective sigma-receptor ligands (+)-pentazocine and 1,3-di(2-tolyl)guanidine (DTG). The inhibition of [3H]DMI binding by sigma- and PCP-receptor ligands was not attributed to PCP1- or PCP2-receptor stimulation, owing to the decreased potency (100-fold) of these ligands in [3H]DMI assays compared with the affinity for brain PCP1 sites, and the ineffectiveness of the PCP2-ligand N-(1-(2-benzo(b)thiophenyl)cyclohexyl)piperidine (BTCP). Scatchard analysis of the inhibition by the sigma-ligands haloperidol and (+)-3-PPP, as well as the PCP1 receptor ligand MK-801, demonstrated noncompetitive interaction with the site bound by [3H]DMI. These studies indicate that bovine adrenomedullary membranes possess a specific receptor for the noradrenaline uptake inhibitor [3H]DMI, which is sensitive to allosteric modulation produced by PCP and sigma-ligands.

Topics: Adrenal Medulla; Animals; Binding Sites; Cattle; Desipramine; Dextromethorphan; Dizocilpine Maleate; Phenazocine; Phencyclidine; Piperidines; Potassium Chloride; Receptors, Opioid, delta; Receptors, Phencyclidine; Tranquilizing Agents

Pigeons were fed a fixed amount of grain-based feed and behavior was observed after administration of doses of ditolyguanidine (DTG), (+)-3-(3-hydroxyphenyl)-N-(1-propyl)-piperidine [(+)-3-PPP], dextromethorphan, haloperidol, (+)-N-allylnormetazocine (NANM), alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine-butanol (BMY-14802) apomorphine, pentobarbital, propranolol, and MK-801. Of the drugs tested, DTG, dextromethorphan, and (+)-3-PPP each produced dose-related increases in the percentage of pigeons exhibiting an emetic response. The emetic response produced by DTG was antagonized by haloperidol and BMY-14802 but not by propranolol. These observations suggest that the emetic response in the pigeon may be mediated by sigma sites and is unlikely to be mediated by phencyclidine receptors.

Topics: Animals; Apomorphine; Columbidae; Dextromethorphan; Dizocilpine Maleate; Dopamine Agents; Guanidines; Haloperidol; Male; Pentobarbital; Phenazocine; Piperidines; Propranolol; Psychotropic Drugs; Pyrimidines; Receptors, Opioid; Receptors, sigma; Vomiting

It has been suggested that sigma receptor antagonists may be useful as antipsychotic drugs and that 5-hydroxytryptamine (5-HT2) receptor antagonists produce improvements of the negative symptoms of schizophrenia. [1-(Cyclopropylmethyl)-4-(2'-(4''-fluorophenyl)-2'- oxoethyl)-piperidine HBr] (DuP 734) is a novel compound with high affinity for the sigma (Ki = 10 nM) and 5-HT2 (Ki = 15 nM) receptors, but low affinity for dopamine receptors (Ki > 1000 nM) as well as 33 other receptors, ion channels and second messenger systems in vitro. DuP 734 did not inhibit the synaptosomal uptake of dopamine, 5-HT or norepinephrine. Oral administration of DuP 734 potently blocked 5-hydroxy-L-trytophan (5-HTP)-induced head twitch in the rat (ED50 = 6.5 mumol/kg), indicating 5-HT2 antagonist activity. Extracellular single-unit recording studies demonstrated that DuP 734 antagonized the effect of the selective sigma ligand (+)-3-(3-hydroxyphenyl-N-(1-propyl) piperidine [(+)-3-PPP] on dopamine neuronal activity in the substantia nigra of the rat with an ED90 of 3.6 mumol/kg i.v. The sigma receptor agonists (+)-SKF 10,047 and phencyclidine both elicited rotational behavior in rats with unilateral lesion of the substantia nigra. The rotational behavior induced by either (+)-SKF 10,047 or phencyclidine was dose-dependently antagonized by DuP 734 with oral ED50 of 8.7 and 19.6 mumol/kg, respectively. The 5-HT2 receptor antagonist ICI 169,369, even at high doses (up to 33 mumol/kg, s.c.), did not antagonize the rotational behavior induced by (+)-SKF 10,047.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antipsychotic Agents; Behavior, Animal; Biogenic Amines; Guinea Pigs; Male; Phenazocine; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, Dopamine; Receptors, Serotonin; Receptors, sigma; Rotation; Serotonin Antagonists

The in vitro binding properties of 1-(cyclopropylmethyl)-4-(2'-(4''-fluorophenyl)-2'-oxoethyl)pipe ridi ne HBr, [3H]DuP 734, a novel sigma receptor ligand, were examined in homogenates of guinea pig brain. Specific [3H]DuP 734 binding (10 microM haloperidol-displaceable) in cerebellum was dependent on pH, temperature and membrane protein concentration, reversible, saturable and of high affinity (KD = 228 +/- 34 pM; Bmax = 3856 +/- 340 fmol/mg protein). [3H]DuP 734 binding was substantially reduced by treating the membrane with proteases and completely abolished by heat denaturation. [3H]DuP 734 binding was unaffected by the presence of ions or guanine nucleotides. The pharmacological characteristics of [3H]DuP 734 binding in cerebellum displayed the same rank order and stereospecificity as previously reported for sigma receptors in brain. [3H]DuP 734-labeled sigma receptors were heterogeneously distributed throughout the central nervous systems with highest densities present in pons/medulla, hypothalamus, spinal cord and cerebellum. In addition to labeling sigma receptors, a second, lower affinity, haloperidol-insensitive [3H] DuP 734 binding site was observed in the cerebral cortex. This second site could not be positively identified as a neuronal receptor because a series of standard compounds were unable to displace [3H]DuP 734 from the haloperidol-insensitive site; only structural analogs of DuP 734 proved effective in displacing [3H]DuP 734 from the haloperidol-insensitive site. In summary, [3H]DuP 734 is a novel ligand that binds with high affinity to sigma receptors in brain.

Topics: Animals; Antipsychotic Agents; Brain; Guanylyl Imidodiphosphate; Hydrogen-Ion Concentration; In Vitro Techniques; Kinetics; Male; Mice; Phenazocine; Phenytoin; Piperidines; Receptors, sigma; Structure-Activity Relationship; Temperature

The binding of four sigma receptor ligands, 3H-(+)-N-allyl-N-normetazocine (3H-(+)-SKF 10,047), 3H-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine (3H-(+)-3-PPP), 3H-haloperidol and 3H-N,N'-di(o-totyl)guanidine (3H-DTG), and the cytochrome P450IID6 ligand and dopamine uptake inhibitor 3H-1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine (3H-GBR 12935) to membranal preparations of rat liver or whole rat brain was examined regarding kinetical properties and inhibition by various compounds with affinity for sigma binding sites or cytochrome P-450. In rat brain the density of binding sites was increased in order (+)-SKF 10,047 less than (+)-3-PPP less than DTG much less than GBR 12935. In liver the corresponding order was (+)-SKF 10,047 less than DTG less than haloperidol less than (+)-3-PPP less than GBR 12935. The inhibition pattern of each ligand was similar in brain and liver, indicating that the binding sites were similar in the two tissues. With the exception of 3H-(+)-SKF 10,047 which appears to bind to a homogeneous haloperidol-sensitive site, there were quite marked differences between the ligands studied, suggesting heterogeneous binding sites. For instance, (+)-SKF 10,047 and progesterone were potent inhibitors of the binding of 3H-(+)-SKF 10,047, 3H-(+)-3-PPP and 3H-haloperidol but inhibited only a minor fraction of the binding of 3H-DTG to the brain and liver preparations. Multiple binding sites were also indicated by the low Hill coefficients found for most of the compounds studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Brain; Cytochrome P-450 Enzyme System; Guanidines; Haloperidol; Kinetics; Ligands; Liver; Male; Phenazocine; Piperazines; Piperidines; Radioligand Assay; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, sigma; Subcellular Fractions

The interaction of various compounds with sigma binding sites was examined in membranes prepared from whole guinea pig brain. Whereas [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine labeled a single population of binding sites exhibiting a Kd of 43 nM, [3H]1,3-di-o-tolylguanidine bound to two sites having Kds of 35 and 212 nM, and to a greater maximum number of sites than [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine. Haloperidol, 1,3-di-o-tolylguanidine, BMY 14802, and (-)-pentazocine each displayed nearly equal affinity for binding sites labeled by [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine and [3H]1,3-di-o-tolylguanidine, whereas (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine was 3 times more potent in inhibiting [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine than [3H]1,3-di-o-tolylguanidine binding. In contrast, (+)-SKF 10,047, (+)-cyclazocine and (+)-pentazocine exhibited more than 9-fold higher affinity for [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine than [3H]1,3-di-o-tolylguanidine binding sites. Dextromethorphan was 15-fold more potent against [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine than [3H]1,3-di-o-tolylguanidine, inhibited [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine binding in a biphasic manner, and inhibited [3H]haloperidol and [3H](+)-SKF 10,047 binding with potencies similar to those obtained against [3H]1,3-di-o-tolylguanidine and [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine, respectively. Phenytoin increased [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine and [3H](+)-SKF 10,047 binding, but did not enhance [3H]1,3-di-o-tolylguanidine or [3H]haloperidol binding. However, the potency of dextromethorphan to inhibit [3H]1,3-di-o-tolylguanidine binding was increased in the presence of phenytoin.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Binding, Competitive; Brain; Dextromethorphan; Dopamine Agents; Guanidines; Guinea Pigs; Haloperidol; In Vitro Techniques; Kinetics; Membranes; Phenazocine; Phenytoin; Piperidines; Receptors, Opioid; Receptors, sigma

JO 1784 ((+)-N-Cyclopropyl-methyl-N-methyl-1,4-diphenyl-1-yl-but-3-en-1-ylami ne, hydrochloride), has been recently described as a selective ligand for the sigma receptor with an IC50 of 39 +/- 8 nM28. In the present study the effects of JO 1784 on experimental induced amnesia were investigated using one trial passive avoidance task in rats. Amnesia was produced by injecting scopolamine (1 mg/kg i.p.) 30 min before the second session (T2) on day 2 of the passive avoidance task. The anti-amnesic effect of JO 1784 was compared with other typical and atypical psychotropic drugs which interact at the sigma and or the phencyclidine site. JO 1784 was studied at 5 doses; 0.0625, 0.25, 1.0, 4.0 and 16.0 mg/kg i.p. ((+)-3-(3-hydroxyphenyl)-N-1-(propyl)piperidine ((+)-3-PPP). Rimcazole, (+)-N-allylnormetazocine ((+)-NANM), 1,3-di(2-tolyl) guanidine (DTG) were studied at 4 doses; 0.25, 1.0, 4.0 and 8.0 mg/kg i.p. All drugs were administered 60 min before the test (T2) on day 2 i.e. 30 min before scopolamine. Piracetam (1000 mg/kg p.o.) administered in the same test conditions was used as a reference compound in each experiment. Of the drugs investigated JO 1784 (0.25, 1.0, 4.0 and 16.0 mg/kg i.p.), (+)-3-PPP (0.25, 1.0 and 4.0 mg/kg i.p.), DTG (1.0, 4.0 and 8.0 mg/kg) and piracetam significantly reversed scopolamine induced amnesia on day 3 (T3). At the lower dose, JO 1784 (0.0625 mg/kg) failed to reverse the amnesic effects of scopolamine on day 3. These results suggest that JO 1784 the selective sigma ligand, may be beneficial in amnesic status.

Topics: Amnesia; Animals; Antipsychotic Agents; Avoidance Learning; Behavior, Animal; Carbazoles; Cinnamates; Cyclopropanes; Dopamine Agents; Dose-Response Relationship, Drug; Guanidines; Ligands; Male; Phenazocine; Piperidines; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, sigma; Scopolamine

1,3-di(2-[5-3H]tolyl)Guanidine ([3H]DTG) was found to bind to a single saturable population of binding sites in human cerebral cortex and NCB20 cells, a second low-affinity site was apparent in guinea pig brain. Displacement studies were performed to determine the pharmacology of the [3H]DTG binding site in these 3 membrane preparations. In human cortical tissue and NCB20 cell membranes the (+)-stereoisomers of benzomorphans displaced binding with Hill coefficients close to one, displayed similar affinity and did not give the biphasic displacement curve characteristic of guinea pig membranes. The pIC50 of the low-affinity component of the sigma binding site in guinea pig brain correlates best with the affinity of drugs for the binding site in human cortex.

Topics: Animals; Brain Chemistry; Cells, Cultured; Cerebral Cortex; Cricetinae; Cricetulus; Dopamine Agents; Guanidines; Guinea Pigs; Humans; Kinetics; Male; Mice; Neuroblastoma; Pentazocine; Phenazocine; Piperidines; Radioligand Assay; Receptors, Opioid; Receptors, sigma; Stereoisomerism; Tumor Cells, Cultured

The effects of sigma ligands, (+)3PPP 3-[3-hydroxyphenyl-N(1-propyl) piperidine] and (-)butaclamol, were evaluated in vivo on the metabolism of dopamine (DA) and in the striatum release of adrenocorticotrophic hormone (ACTH) and prolactin in the rat and changes in levels of cyclic guanosine monophosphate (cGMP) in the cerebellum of the mouse and compared with the effects of (+)NANM (N-allyl-normetazocine, SKF 10,047) and (+)pentazocine. Both (+)3PPP and (-) butaclamol decreased the release of prolactin and did not affect the metabolism of DA. N-Allyl-normetazocine and (+)pentazocine increased release of prolactin and have been shown previously to increase the metabolism of DA. All four ligands increased release of ACTH; however, only the increases caused by (+)NANM and (+)pentazocine were reversed by pretreatment with CPP, a N-methyl-D-aspartate (NMDA) receptor antagonist. (+)Pentazocine and (+)NANM inhibited the NMDA receptor-mediated changes in levels of cGMP in the cerebellum of the mouse, while (+)3PPP and (-)butaclamol did not attenuate the response to NMDA. In addition to further confirming a functional interaction between sigma receptors and NMDA receptors, these studies divide the observed effects of putative sigma ligands into two groups, characterized by benzomorphan compounds and non-benzomorphan compounds, suggesting the possibility of subtypes at sigma receptor in vivo.

Topics: Adrenocorticotropic Hormone; Animals; Brain; Butaclamol; Cerebellum; Corpus Striatum; Cyclic GMP; Dopamine; Dopamine Agents; Male; Mice; Pentazocine; Phenazocine; Piperidines; Prolactin; Rats; Rats, Inbred Strains; Receptors, N-Methyl-D-Aspartate; Receptors, Opioid; Receptors, sigma

The interaction of several sigma and PCP receptor ligands with the norepinephrine uptake carrier was investigated in the rat tail artery and brain. These ligands include haloperidol; (+)- and (-) 3-(3-hydroxy- phenyl)-N-(1-propyl)piperidine (3-PPP), (+/-)-BMY 14802, [(+/-) alpha-(4-fluoro- phenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol]; (+)-SKF 10047, [(+/-)-N-allyl-N-normetazocine]; 1,3-di-ortho-tolyl-guanidine; rimcazole (BW 234U), [cis-9-[3-(3,5-dimethyl-1-piperazinyl)propyl] carbazole dihydrochloride]; and MK 801, [(+)-5-methyl-10,1 1-dihydro-5H-dibenzo[a, d]cyclohepten-5, 10-imine maleate]. Our results show that all ligands used, except 1,3-di-ortho-tolyl-guanidine, inhibit both neuronal [3H]norepinephrine accumulation in the rat tail artery and specific [3H] desmethylimipramine binding in the rat brain. Except for (+)-SKF 10047, the order of potency of the ligands used for inhibiting neuronal [3H]norepinephrine accumulation in the rat tail artery was similar to that measured for inhibition of specific [3H]desmethylimipramine binding in the rat brain. Despite these similarities, our results also suggest that haloperidol, (+)- and (-)3-PPP, MK 801, rimcazole and cocaine interact with the [3H]norepinephrine site in the rat tail artery and with the [3H]desmethylimipramine binding site in the rat brain in a complex fashion. These studies demonstrate an important action on the norepinephrine carrier by these sigma and PCP ligands in the rat tail artery and brain.

Topics: Animals; Biological Transport; Brain; Desipramine; Dizocilpine Maleate; Male; Norepinephrine; Phenazocine; Piperidines; Rats; Rats, Inbred Strains; Receptors, Neurotransmitter; Receptors, Opioid; Receptors, Phencyclidine; Receptors, sigma; Tail; Vasoconstriction

Our preliminary studies indicated that certain monoamine oxidase (MAO) inhibitors display high affinity for the sigma-binding sites labeled with (+)[3H]-3-(3-hydroxyphenyl)-N-1-(propyl)piperidine [(+)[3H]-3-PPP] in C57BL/6 mouse brain (Itzhak, Y., and Kassim, C. D.: Eur. J. Pharmacol. 176: 107-108, 1990). In the present study, the drug specificity and the subcellular distribution of (+)[3H]-3-PPP, (+)[3H]-N-allylnormetazocine [(+)[3H]SKF 10047] and [3H]1,3-di-o-tolyl-guanidine ([3H]DTG) binding sites in C57BL/6 mouse brain were investigated, and the properties of clorgyline interaction with the (+)-3-PPP/sigma-binding site(s) were examined. (+)[3H]-3-PPP binding, but not [3H]DTG binding, is inhibited by low concentrations (nM) of the dextrorotatory (+)-isomers of SKF 10047, 3-PPP and deprenyl and the type A MAO inhibitor, clorgyline. The haloperidol-sensitive/(+)[3H]SKF 10047 binding sites display virtually identical sensitivity towards the MAO inhibitors as (+)-3-PPP binding sites. These observations suggest a distinction between [3H]DTG and (+)[3H]-3-PPP/(+)[3H]SKF 10047 binding sites in the mouse brain. Clorgyline interaction with (+)-3-PPP/sigma-sites is competitive and reversible unlike the interaction of clorgyline with MAO-A. The sigma-ligands tested do not inhibit MAO activity and bind to sites that are apparently distinct from the MAO binding sites labeled with [3H]-N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. However, the mitochondrial fraction of the mouse brain that expresses MAO activity and high density of [3H]-N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine binding sites also comprises high density of (+)-3-PPP/(+)SKF 10047 binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Binding Sites; Brain; Guanidines; In Vitro Techniques; Ligands; Male; Mice; Mice, Inbred C57BL; Monoamine Oxidase Inhibitors; Phenazocine; Piperidines; Receptors, Opioid; Receptors, sigma

Whole cell voltage clamp studies were performed on NCB-20 cells to examine physiological responses to drugs possessing affinities for sigma receptors. Those drugs [haloperidol, alpha-(4-fluoro-phenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazinebutano l (BMY-14802), pentazocine, N-allylnormetazocine (SKF-10047), 3-(3-hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP), phencyclidine, 1-[1-(2-thienyl)cyclohexyl]piperidine (TCP), (+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclohepten-5,10-imine maleate (MK-801)] caused an apparent inward current, which was due to blockade of a tonic, outward potassium current. The rank order of drug potencies in producing this effect generally resembled the rank orders of sigma-receptor affinities for the drugs, except that a reverse stereoselectivity was observed for several drugs. [3H](+)-SKF-10047 labeled two sites in intact NCB-20 cells (Kd = 49 nM, Bmax = 1.0 pmol/mg protein and Kd = 9.6 microM, Bmax = 69 pmol/mg protein). The high affinity site was similar pharmacologically to the sigma receptor assayed in membrane fragments from NCB-20 cells. However, the low affinity site showed a slightly different profile, highlighted by a reverse stereoselectivity. The rank order of drug potencies was as follows at the low affinity site: haloperidol greater than BMY-14802 greater than (-)-pentazocine greater than (+)-pentazocine greater than (-)-SKF-10047 greater than (-)-3-PPP greater than (+)-SKF-10047 greater than (+)-3-PPP greater than phencyclidine greater than TCP greater than MK-801.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cricetinae; Cricetulus; Hybrid Cells; Ligands; Mice; Neuroblastoma; Phenazocine; Piperidines; Potassium Channels; Receptors, Opioid; Receptors, sigma; Stereoisomerism; Tumor Cells, Cultured

We have characterized the actions of several sigma receptor ligands on the electrically evoked, neurogenic contractions of the mouse isolated vas deferens. (-)SKF 10,047 was significantly more potent than (+)SKF 10,047 in potentiating twitch contractions and was equipotent with (+)3-PPP. Rimcazole (1 and 3 microM) antagonised the potentiation induced by 100 microM (+)SKF 10,047 and, to a lesser extent, that induced by 30 microM (-)SKF 10,047 but increased that elicited by (+)3-PPP (30 microM). This apparent contradiction may arise from sigma agonists acting in this tissue at both sigma and non-sigma sites.

Topics: Animals; Antipsychotic Agents; Carbazoles; In Vitro Techniques; Male; Mice; Mice, Inbred DBA; Muscle, Smooth; Phenazocine; Piperidines; Stereoisomerism; Vas Deferens

SKF 10,047 (N-allylnormetazocine) was found to be neuroprotective against glutamate-induced excitotoxicity in our model system of energy-stressed neurons which rapidly succumb to glutamate via N-methyl-D-aspartate (NMDA) receptor-mediated events. The 50% protective concentration (PC50) of the (+) and (-) enantiomers was 3.3 microM and 9 microM, respectively, against the toxic action of 100 microM glutamate. Protection by SKF 10,047 seemed to be mediated by the lower-affinity phencyclidine (PCP) binding site rather than the higher-affinity sigma-site since the potent sigma-ligand (+)-3-(3-hydroxyphenyl-N-1-propyl)piperidine [+)-3-PPP) did not protect at concentrations up to 2 mM. A reversed stereoselectivity was apparent for neuroprotection since (-)-3-PPP was weakly protective with a PC50 of 1.5 mM. These data suggest that energy-stressed rat cerebellar granule cells are a useful model for identifying neuroprotective agents, as shown by SKF 10,047.

Topics: Animals; Cell Survival; Cells, Cultured; Cerebellum; Dopamine Agents; Glutamates; Glutamic Acid; Neurons; Neurotoxins; Phenazocine; Phencyclidine; Piperidines; Rats; Receptors, N-Methyl-D-Aspartate; Receptors, Neurotransmitter; Receptors, Phencyclidine

Topics: Animals; Binding, Competitive; Brain; Guinea Pigs; In Vitro Techniques; Kinetics; Pentazocine; Phenazocine; Piperidines; Receptors, Opioid; Receptors, sigma

The functional effects of sigma and PCP receptor ligands were examined in the perfused rat tail artery. The following ligands were studied: haloperidol; (+)-3-PPP [(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine]; (+-)-BMY 14802 [(+-)-alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol]; DTG [1,3-di-orthotolyl-guanidine]; rimcazole (BW 234U) [cis-9-[3-(3,5-dimethyl-1-piperazinyl)propyl]carbazole dihydrochloride]; (+)-SKF 10047 [(+)-N-allyl-N-normetazocine]; TCP, [1-[1-(2-thienyl)cyclohexyl] piperidine]; and MK 801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate]. (+)-3-PPP, (+)-SKF 10047, MK 801 and TCP potentiated contractile responses to norepinephrine, an effect which was blocked by cocaine implying an action of these agents on monoamine uptake. In the presence of cocaine an additional postjunctional inhibitory action of (+)-3-PPP and (+)SKF 10047 on norepinephrine-induced contractile responses was unveiled. In contrast, haloperidol, (+/-)-BMY 14802, rimcazole and DTG inhibited contractile responses to norepinephrine. Haloperidol, (+/-)-BMY 14802 and (+)-SKF 10047 (+ uptake blockade) also inhibited contractile responses to serotonin. The order of potency for inhibition of norepinephrine-induced contractions was haloperidol greater than (+/-)-BMY 14802 greater than (+)-3-PPP greater than rimcazole greater than (+)-SKF 10047 (+ uptake blockade) greater than DTG. These studies demonstrate the lack of selectivity of many sigma and PCP ligands, significant effects on norepinephrine uptake, as well as the potential utility of the rat tail artery to explore the functional properties of these ligands.

Topics: Animals; Cocaine; Desoxycorticosterone; Haloperidol; Male; Norepinephrine; Phenazocine; Piperidines; Rats; Rats, Inbred Strains; Receptors, Neurotransmitter; Receptors, Opioid; Receptors, Phencyclidine; Receptors, sigma; Serotonin; Vasoconstriction

Several phencyclidine (PCP) and sigma receptor ligands were examined for their effects on a single trial passive avoidance test in rats. Rats were administered the PCP receptor ligands (+)-5-methyl-10,11-dihydro-5Hdibenzo[a,d]cyclohepten-5,10-im ine maleate (MK-801), PCP, ketamine or the sigma receptor ligands (+)-N-allylnormetazocine ((+)-NANM), (+)-pentazocine, (+)-3-(3-hydroxyphenyl)-N-n-propylpiperidine ((+)-3-PPP) or 1,3-Di(2-[5-3H]tolyl)guanidine (DTG) subcutaneously prior to acquisition of the passive avoidance response, and tested 24 h later for retention. MK-801 (0.1-0.3 mg/kg), PCP (0.54-1.7 mg/kg), ketamine (10.0-17.2 mg/kg) and (+)-N-allylnormetazocine (5.4-10.0 mg/kg) produced significant memory deficits. (+)-Pentazocine (54 mg/kg) and (+)-3-PPP (30 mg/kg) also produced retention deficits, but at significantly higher doses. DTG (0.3-3.0 mg/kg s.c.) had no effect on retention. There was a positive correlation between production of retention deficits and the compounds' PCP receptor binding affinity. The results suggest that the sigma receptor is not involved in learning the passive avoidance response.

Topics: Animals; Avoidance Learning; Dibenzocycloheptenes; Dizocilpine Maleate; Dose-Response Relationship, Drug; Ketamine; Ligands; Male; Memory; Pentazocine; Phenazocine; Phencyclidine; Piperidines; Rats; Rats, Inbred Strains; Receptors, Neurotransmitter; Receptors, Phencyclidine; Retention, Psychology

Irradiation of rat brain membranes with light of 254 nm, a treatment which modifies ultra-violet absorbing residues in proteins, decreased binding of both [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ([ 3H](+)-3-PPP) and [3H]1,3-di-o-tolylguanidine ([3H]DTG) to sigma receptors. For [3H](+)-3-PPP, this was due to a decreased Bmax. In contrast, irradiation markedly increased binding of [3H](+)-N-allylnormetazocine ([3H](+)-SKF 10,047) due to a decrease in the Kd. Both unlabeled DTG and haloperidol were competitive inhibitors of [3H](+)-3-PPP binding to untreated membranes, causing an increase in the Kd and no change in the Bmax. The benzomorphans, (+)-SKF 10,047 and (+)-pentazocine, were uncompetitive inhibitors, causing a decrease in both the Kd and Bmax for [3H](+)-3-PPP. Finally, the ability of DTG and (+)-3-PPP to inhibit binding of [3H](+)-SKF 10,047 was markedly reduced by ultra-violet irradiation, whereas irradiation had little effect on the potency of unlabeled (+)-SKF 10,047 and (+)-pentazocine. These data suggest that sigma-related (+)-benzomorphans and non-benzomorphans interact either with distinct, allosterically coupled sites on the same sigma receptor macromolecule or with different populations of sigma receptor types.

Topics: Animals; Brain; In Vitro Techniques; Male; Membranes; Models, Biological; Phenazocine; Piperidines; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, Opioid, delta; Synaptosomes; Ultraviolet Rays

The effect of guanine nucleotides and ions on (+)-[3H]3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [+ )-[3H]3-PPP), (+)-N-[3H]allylnormetazocine ((+)-[3H]SKF 10047) and [3H]1-[1-(3-hydroxyphenyl)-cyclohexyl]piperidine ([3H]PCP-3-OH) specific binding to rat brain membranes was examined. These 3 compounds are proposed as prototypical ligands for the labeling of the sigma- and phencyclidine (PCP)-receptor subtypes. Competition binding experiments of (+)-SKF 10047 with (+)-[3H]3-PPP yielded a biphasic inhibition curve which transformed to a monophasic curve when membranes were incubated in the presence of Gpp(NH)p (0.1 mM). The common (+)-[3H]3-PPP/(+)-SKF 10047 binding component is more susceptible to Gpp(NH)p than the high affinity [3H]PCP-3-OH/(+)-SKF 10047 common binding component. Low affinity [3H]PCP-3-OH binding, which may represent a PCP-selective site, is not affected by GTP and Gpp(NH)p. Mono- and divalent cations markedly inhibit high affinity [3H]PCP-3-OH binding but they had a differential inhibitory effect on the binding of the other radioligands tested. These findings suggest differences in the regulation of multiple psychotomimetic (sigma- and PCP) binding sites by guanine nucleotides and ions.

Topics: Animals; Binding, Competitive; Brain; Cations; Guanine Nucleotides; Male; Phenazocine; Phencyclidine; Piperidines; Rats; Receptors, Neurotransmitter; Receptors, Phencyclidine; Subcellular Fractions

The pharmacological specificity of representative psychotomimetic agents such as phencyclidine (PCP) analogs, opiate benzomorphans and several antipsychotic agents was assessed for the sigma and PCP binding sites. In a series of binding experiments, in rat brain membranes, sigma and PCP binding sites were labeled with [3H]-1-[1-(3-hydroxyphenyl)cyclohexyl]piperidine [( 3H]PCP-3-OH), (+) [3H]-N-allylnormetazocine [(+) [3H]SKF 10047] and (+) [3H]-3-[3-hydroxy-phenyl]-N-(1-propyl)piperidine [(+) [3H]-3-PPP]. PCP analogs inhibit potently high affinity [3H]PCP-3-OH binding and (+) [3H]SKF 10047 binding, moderately the low affinity binding component of [3H]PCP-3-OH and very weakly (+) [3H]-3-PPP binding. (+)SKF 10047 and cyclazocine are potent to moderate inhibitors of (+) [3H]SKF 10047, high affinity [3H]PCP-3-OH and (+) [3H]-3-PPP binding, but extremely weak inhibitors of low affinity [3H]PCP-3-OH binding. The antipsychotic agents display high affinity for (+) [3H]-3-PPP binding sites, moderate affinity for (+) [3H]SKF 10047 sites and have no effect on either the high or low affinity [3H]PCP-3-OH binding. The present data further support the existence of multiple sigma and PCP binding sites.

Topics: Animals; Antipsychotic Agents; Binding, Competitive; Haloperidol; In Vitro Techniques; Male; Phenazocine; Phencyclidine; Piperidines; Psychotropic Drugs; Rats; Receptors, Neurotransmitter; Receptors, Opioid; Receptors, Phencyclidine; Receptors, sigma

(+)[3H]SKF 10,047 and (+)[3H]3-PPP label a homogeneous population of sites in NCB-20 cell membranes that apparently represent benzomorphan specific binding sites previously reported for this cell line. Their drug specificity indicates that these sites are very similar to sigma receptor binding sites labeled in brain tissues by these ligands and do not represent PCP receptors.

Topics: Animals; Brain; Cells, Cultured; Cricetinae; Cricetulus; Hybrid Cells; Kinetics; Neuroblastoma; Phenazocine; Phencyclidine; Piperidines; Receptors, Opioid; Receptors, Opioid, delta; Stereoisomerism

The benzomorphan opioid, SKF 10,047, is the prototypical agonist for the sigma receptor. In this study, pharmacological and autoradiographic analyses reveal that (+)-[3H]SKF 10,047 labels two sites in brain: a high affinity site resembling the sigma receptor and a second site, labeled with lower affinity by (+)-[3H] SKF 10,047, similar to the phencyclidine (PCP) receptor. The drug specificity of the high affinity site for (+)-[3H]SKF 10,047 resembles that of the putative sigma receptor labeled with (+)-[3H]-3-[3-hydroxyphenyl]-N-(1-propyl)piperidine [(+)-[3H]-3-PPP], being potently inhibited by (+)-3-PPP, haloperidol and (+/-)-pentazocine, and demonstrating stereoselectivity for the (+)-isomer of SKF 10,047. In contrast, these drugs are weak in inhibiting binding of (+)-[3H]SKF 10,047 to the low affinity site, whereas PCP analogs, such as 1-[1-(2-thienyl)cyclohexyl]piperidine (TCP) and 1-[1-(m-aminophenyl)cyclohexyl]piperidine (m-NH2-PCP), are potent inhibitors. No stereoselectivity for the isomers of SKF 10,047 is noted at the low affinity binding site. Autoradiographic localizations of high affinity (+)-[3H]SKF 10,047 binding sites closely resemble those of (+)-[3H]-3-PPP labeled sites with high levels of binding in the hippocampal pyramidal cell layer, hypothalamus, pontine and cranial nerve nuclei and cerebellum. By contrast, low affinity (+)-[3H]SKF 10,047 sites are most abundant in nonpyramidal layers of the hippocampus, the cerebral cortex and thalamic nuclei, similar to the distribution of [3H]TCP labeled PCP receptors.

Topics: Animals; Autoradiography; Binding, Competitive; Brain Chemistry; In Vitro Techniques; Kinetics; Male; Phenazocine; Phencyclidine; Piperidines; Radioligand Assay; Rats; Rats, Inbred Strains; Receptors, Neurotransmitter; Receptors, Opioid; Receptors, Phencyclidine; Receptors, sigma; Stereoisomerism

The functional significance of the reported affinity of (+)-3-PPP and (+)-N-allylnormetazocine (NANM) for the same binding site in rat brain membranes was assessed by studying (+)-3-PPP as a agonist and antagonist of (+)-NANM in rats trained to discriminate 5.0 mg/kg (+)-NANM from saline. Over a wide dose range, (+)-3-PPP was able to block the discriminative stimulus effects of (+)-NANM, with complete antagonism at 1.0 mg/kg i.p. Since (+)-NANM is a prototype sigma-opioid agonist, (+)-3-PPP is a good candidate for being a competitive sigma antagonist.

Topics: Animals; Binding Sites; Conditioning, Operant; Discrimination, Psychological; Generalization, Stimulus; Phenazocine; Piperidines; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, Opioid, delta

In rats trained to discriminate the prototypic sigma receptor agonist, (+)-N-Allylnormetazocine [(+)-N-Allylnormetazocine [(+)-NANM/SKF 10,047], from saline, the (+)- but not the (-)-isomer of 3-(3-hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP) produced (+)-NANM-like discriminative stimuli. (+)-3-PPP binds stereo selectively to the (+)-NANM binding site, but not to the phencyclidine binding site. Additionally, phencyclidine was found to produce (+)-NANM-like discriminative stimuli. Although the 3-PPP isomers were shown to produce changes in central dopaminergic activity (Hjorth et al. Life Sci 37, 673, 1985), the discriminative stimulus properties of (+)-3-PPP are apparently not mediated via the dopaminergic system. This hypothesis is supported by the fact that apomorphine did not produce (+)-NANM-like discriminative stimuli. These stimuli are thus non-dopaminergic and may be due to the (+)-3-PPP actions at the sigma binding site. However, it is possible that (+)-NANM, PCP, and (+)-3-PPP may have common non-sigma pharmacologic properties that account for the similar discriminative stimulus properties of these compounds.

Topics: Animals; Apomorphine; Discrimination Learning; Dose-Response Relationship, Drug; Isomerism; Male; Phenazocine; Phencyclidine; Piperidines; Rats; Rats, Inbred F344

Topics: Autoradiography; Brain; Humans; In Vitro Techniques; Membranes; Phenazocine; Phencyclidine; Piperidines; Receptors, Neurotransmitter; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Phencyclidine