piperidines and Morphine-Dependence

A growing body of evidence indicates that the mesolimbic dopaminergic (DAergic) pathway projecting from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc.) play a critical role in the initiation of psychological dependence on morphine. As well as DAergic system, the involvement of non-DAergic neurotransmitter and neuromodulator systems in rewarding effects induced by morphine has been recently documented. We previously demonstrated that the morphine-induced rewarding effect was dramatically suppressed by co-treatment with NMDA receptor antagonists, such as dizocilpine (MK-801), ketamine and ifenprodil. Therefore, we propose here that inhibiting the N-methyl-D-aspartate (NMDA) receptor and its associated protein kinase in the N.Acc. is useful for the treatment for psychological dependence on morphine. The following review provides a summary of recent our findings regarding the role of NMDA receptor and its associated protein kinase in the development of psychological dependence on morphine.

Topics: Animals; Disks Large Homolog 4 Protein; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Humans; Intracellular Signaling Peptides and Proteins; Ketamine; Membrane Proteins; Mice; Morphine Dependence; Nucleus Accumbens; Piperidines; Protein Kinase C; Receptors, N-Methyl-D-Aspartate; Signal Transduction

Topics: Animals; Conotoxins; Disease Models, Animal; Excitatory Amino Acid Antagonists; Hippocampus; Locomotion; Male; Mice; Morphine Dependence; Naloxone; Piperidines; Receptors, N-Methyl-D-Aspartate; Spatial Memory

Brain reward and motivation circuit begin from the ventral tegmental area (VTA) that its dopaminergic terminals project to various regions of the brain including the nucleus accumbens (NAc). This reward circuit is influenced by drugs of abuse such as morphine and cannabinoid. The present study tried to investigate the role of the intra-accumbal CB1 receptor in the c-fos level and pCREB/CREB ratio in the NAc and the VTA during reinstatement phase of morphine-induced conditioned place preference (CPP) by western blotting. The present data reveals that intra-accumbal administration of CB1 agonist, WIN55,212-2 (0.5, 1 and 2 mM/0.5 μl DMSO) before/during extinction period of morphine-induced CPP, significantly decreased the NAc and the VTA c-fos protein level in the reinstatement phase; whereas the pre-reinstatement administration of the CB1 agonist, increased the c-fos protein level. Intra-accumbal administration of the CB1 agonist during the extinction period of morphine-induced CPP reduced the pCREB/CREB ratio in the NAc. Also, the present data show that intra-accumbal administration of CB1 antagonist, AM251 (15, 45 and 90 μM/0.5 μl DMSO) during/after extinction period of morphine-induced CPP affects the NAc and the VTA c-fos protein level in the reinstatement phase. Also, intra-NAc microinjection of AM251 during the extinction period reduced pCREB/CREB ratio in these regions. In conclusion, the results presented here provide compelling evidence of the modulation and involvement of the c-fos and the CREB molecules in the cannabinoid-opioid interaction of the brain reward system in the CPP paradigm.

Topics: Animals; Benzoxazines; Cannabinoid Receptor Modulators; Cyclic AMP Response Element-Binding Protein; Dose-Response Relationship, Drug; Drug-Seeking Behavior; Extinction, Psychological; Male; Morphine; Morphine Dependence; Morpholines; Naphthalenes; Narcotics; Nucleus Accumbens; Phosphorylation; Piperidines; Proto-Oncogene Proteins c-fos; Pyrazoles; Rats, Wistar; Receptor, Cannabinoid, CB1; Ventral Tegmental Area

Inhibition of the endocannabinoid catabolic enzymes, monoacylglycerol lipase (MAGL) or fatty acid amide hydrolase (FAAH) attenuates naloxone-precipitated opioid withdrawal signs in mice via activation of CB1 receptors. Complete FAAH inhibition blocks only a subset of withdrawal signs, whereas complete MAGL inhibition elicits enhanced antiwithdrawal efficacy, but is accompanied with some cannabimimetic side effects. Thus, the primary objective of the present study was to determine whether combined, full FAAH inhibition and partial MAGL represents an optimal strategy to reduce opioid withdrawal. To test this hypothesis, we examined whether combined administration of high-dose of the FAAH inhibitor PF-3845 and low-dose of the MAGL inhibitor JZL184, as well as the novel dual FAAH-MAGL inhibitor SA-57, which is 100-fold more potent in inhibiting FAAH than MAGL, would prevent spontaneous withdrawal in morphine-dependent mice, a model with greater face validity than precipitating withdrawal with μ-opioid receptor antagonists. Strikingly, a combination of low-dose JZL184 and high-dose PF-3845 as well as the dual inhibitor SA-57 reduced all abrupt withdrawal signs (ie, platform jumping, paw flutters, head shakes, diarrhea, and total body weight loss), but did not elicit any cannabimimetic side effects. In addition, JZL184 or PF-3845 blocked naloxone-precipitated hypersecretion in morphine-dependent small intestinal tissue. Collectively, these results are the first to show that endocannabinoid catabolic enzyme inhibitors reduce abrupt withdrawal in morpine-dependent mice and are effective in a novel in vitro model of opioid withdrawal. More generally, these findings support the idea that joint MAGL and FAAH inhibition represents a promising approach for the treatment of opioid dependence.

Topics: Amidohydrolases; Animals; Benzodioxoles; Endocannabinoids; Enzyme Inhibitors; Male; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Monoacylglycerol Lipases; Morphine; Morphine Dependence; Piperidines; Substance Withdrawal Syndrome

Choice procedures have indicated that the relative reinforcing effectiveness of opioid drugs increases during opioid withdrawal. The demand curve, an absolute measure of reinforcer value, has not been applied to this question. The present study assessed whether mild morphine withdrawal would increase demand for or choice of remifentanil or cocaine. Four rhesus monkeys chose between remifentanil and cocaine during daily sessions. Demand curves for both drugs were subsequently obtained. The effects of daily injections of 3.2 mg/kg morphine on both choice and demand for these drugs was assayed 3 and 20.5 hr after each morphine injection, and then during a postmorphine period. Three hours following morphine injections, choice of remifentanil over cocaine decreased and demand for remifentanil--but not cocaine--became more elastic. During morphine withdrawal (20.5 hr postinjection), choice of remifentanil increased and remifentanil demand became more inelastic in 3 of 4 monkeys. Cocaine demand also became more inelastic during this period. Four to five weeks following the morphine regimen, demand for both drugs was more inelastic relative to the initial determination. The results suggest that both the relative and absolute reinforcing effectiveness of remifentanil decreased following morphine administration and increased during morphine withdrawal. The absolute reinforcing effectiveness of cocaine also increased during morphine withdrawal. In addition, extended exposure to drug self-administration and/or exposure to the morphine regimen produced long-term increases in demand for both drugs.

Topics: Analgesics, Opioid; Animals; Choice Behavior; Cocaine; Conditioning, Operant; Dopamine Uptake Inhibitors; Dose-Response Relationship, Drug; Female; Infusions, Intravenous; Macaca mulatta; Male; Morphine; Morphine Dependence; Motivation; Piperidines; Remifentanil; Substance Withdrawal Syndrome

In this study, the use-dependent, nicotinic receptor antagonist bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate (BTMPS) was evaluated for its ability to attenuate the adverse consequences associated with morphine in rats in all three phases of an abstinence model of drug seeking: self-administration, acute withdrawal, and delayed test of drug seeking. Rats were allowed to self-administer morphine (FR1 schedule) with an active response lever, on a 24 h basis inside operant chambers, for 14 days. Each rat was subsequently evaluated for stereotypical behaviors associated with spontaneous morphine withdrawal. Rats were then placed in standard housing cages for a six week period of protracted abstinence from morphine. After this period, each rat was placed back into its respective operant chamber for a 14 day assessment of unrewarded drug seeking responses. BTMPS was administered to the animals in all three clinically relevant phases in three separate sets of experiments. BTMPS treatment during the self-administration phase resulted in up to a 34% reduction of lever responses to morphine when compared to vehicle treated control animals, as well as a 32% reduction in the dose of morphine self-administered. When given during self-administration and acute withdrawal, BTMPS treatment decreased acute withdrawal symptoms (up to 64%) of morphine use and reduced (up to 45%) drug seeking responses after six weeks of protracted withdrawal compared to control animals. BTMPS treatment after six weeks of abstinence from morphine had no effect. These results offer insight into the role of central cholinergic receptors in the onset and maintenance of drug addiction.

Topics: Animals; Behavior, Addictive; Decanoic Acids; Disease Models, Animal; Male; Morphine; Morphine Dependence; Nicotinic Antagonists; Piperidines; Rats; Rats, Wistar; Self Administration; Substance Withdrawal Syndrome

Δ(9)-Tetrahydrocannbinol (THC), the primary active constituent of Cannabis sativa, has long been known to reduce opioid withdrawal symptoms. Although THC produces most of its pharmacological actions through the activation of CB(1) and CB(2) cannabinoid receptors, the role these receptors play in reducing the variety of opioid withdrawal symptoms remains unknown. The endogenous cannabinoids, N-arachidonoylethanolamine (anandamide; AEA) and 2-arachidonylglycerol (2-AG), activate both cannabinoid receptors but are rapidly metabolized by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively. The objective of this study was to test whether increasing AEA or 2-AG, via inhibition of their respective hydrolytic enzymes, reduces naloxone-precipitated morphine withdrawal symptoms in in vivo and in vitro models of opioid dependence. Morphine-dependent mice challenged with naloxone reliably displayed a profound withdrawal syndrome, consisting of jumping, paw tremors, diarrhea, and weight loss. THC and the MAGL inhibitor 4-nitrophenyl 4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate (JZL184) dose dependently reduced the intensity of most measures through the activation of CB(1) receptors. JZL184 also attenuated spontaneous withdrawal signs in morphine-dependent mice. The FAAH inhibitor N-(pyridin-3-yl)-4-(3-(5-(trifluoromethyl)pyridin-2-yloxy)benzyl)-piperdine-1-carboxamide (PF-3845) reduced the intensity of naloxone-precipitated jumps and paw flutters through the activation of CB(1) receptors but did not ameliorate incidence of diarrhea or weight loss. In the final series of experiments, we investigated whether JZL184 or PF-3845 would attenuate naloxone-precipitated contractions in morphine-dependent ilea. Both enzyme inhibitors attenuated the intensity of naloxone-induced contractions, although this model does not account mechanistically for the autonomic withdrawal responses (i.e., diarrhea) observed in vivo. These results indicate that endocannabinoid catabolic enzymes are promising targets to treat opioid dependence.

Topics: Amidohydrolases; Animals; Arachidonic Acid; Behavior, Animal; Benzodioxoles; Brain Chemistry; Cannabinoid Receptor Modulators; Diarrhea; Dronabinol; Electric Stimulation; Endocannabinoids; Hydrolysis; Ileum; Male; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Mice, Knockout; Monoacylglycerol Lipases; Morphine Dependence; Muscle Contraction; Naloxone; Narcotic Antagonists; Piperidines; Prostaglandins; Pyridines; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Substance Withdrawal Syndrome; Weight Loss

Converging evidence suggests that the endogenous cannabinoid (eCB) system is involved in extinction of learned behaviours. Using operant and classical conditioning procedures, the potential of the fatty acid amide (FAAH) inhibitor, URB-597, and the CB(1) antagonist/inverse agonist, SR141716, to promote and inhibit (respectively) extinction of learned responses previously motivated by either rewarding or aversive stimuli was investigated. In the operant conditioning procedure (Expt. 1), rats previously trained to lever press for sucrose reward were administered URB-597 (0.3 mg/kg) or the CB(1) antagonist/inverse agonist SR141716 (2.5 mg/kg) prior to each of three extinction trials. In the conditioned floor preference procedure (Expts 2a-d), rats trained to associate morphine with one of two distinctive floors were administered one of several doses of the CB(1) antagonist/inverse agonist, AM-251 (Expt 2a) or URB-597 (Expt 2b and 2d) prior to each extinction/test trial wherein a choice of both floors was presented and prior to forced exposure to each floor (Expt 2c). In the conditioned floor aversion procedure (Expt. 3), rats trained to associate a naloxone-precipitated morphine withdrawal with a floor cue were administered URB-597 or SR141716 prior to each of 24 extinction/testing trials. URB-597 did not promote and SR141716 did not reduce extinction rates for sucrose reward-induced operant responding (Expt. 1) or morphine-induced conditioned floor preference (Expts. 2a-d). In contrast, URB-597 facilitated, whereas SR141716 impaired, extinction of the conditioned floor aversion (Expt. 3). These data support previous reports that the eCB system selectively facilitates extinction of aversive memories. URB-597 may prove useful in targeting extinction of aversively motivated behaviours.

Topics: Amidohydrolases; Animals; Benzamides; Cannabinoid Receptor Modulators; Carbamates; Choice Behavior; Conditioning, Psychological; Dietary Sucrose; Extinction, Psychological; Female; Injections, Intraperitoneal; Injections, Subcutaneous; Male; Morphine; Morphine Dependence; Naloxone; Narcotic Antagonists; Narcotics; Piperidines; Pyrazoles; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Reinforcement Schedule; Rimonabant; Species Specificity; Substance Withdrawal Syndrome

ZC88 is a novel non-peptide N-type voltage-sensitive calcium channel blocker synthesized by our institute. In the present study, the oral analgesic activity of ZC88 in animal models of acute and neuropathic pain, and functional interactions between ZC88 and morphine in terms of analgesia, tolerance and dependence were investigated. In mice acetic acid writhing tests, ZC88 (10-80 mg/kg) administered by oral route showed significant antinociceptive effects in a dose-dependent manner. The ED50 values of ZC88 were 14.5 and 14.3 mg/kg in male and female mice, respectively. In sciatic nerve chronic constriction injury rats, mechanical allodynia was ameliorated by oral administration of ZC88 at doses of 14, 28 and 56 mg/kg, suggesting ZC88 relieved allodynic response of neuropathic pain. When concurrently administered with morphine, ZC88 (20-80 mg/kg) dose-dependently potentiated morphine analgesia and attenuated morphine analgesic tolerance in hot-plate tests. ZC88 also prevented chronic exposure to morphine-induced physical dependence and withdrawal, but not morphine-induced psychological dependence in conditioned place preference model. These results suggested that ZC88, a new non-peptide N-type calcium channel blocker, had notable oral analgesia and anti-allodynia for acute and neuropathic pain. ZC88 might be used in pain relief by either application alone or in combination with opioids because it enhanced morphine analgesia while prevented morphine-induced tolerance and physical dependence.

Topics: Acetic Acid; Analgesics; Analgesics, Opioid; Animals; Calcium Channel Blockers; Calcium Channels, N-Type; Conditioning, Operant; Drug Tolerance; Mice; Morphine; Morphine Dependence; Naloxone; Narcotic Antagonists; Pain; Pain Measurement; Peripheral Nervous System Diseases; Physical Stimulation; Piperidines; Rats; Rats, Sprague-Dawley; Reaction Time; Sciatic Neuropathy

Glutamate receptors are known to be densely distributed in the forebrain rewarding circuits, and glutamatergic transmission is actively involved in the regulation of rewarding and reinstating effects of drugs of abuse. Here we investigated the possible involvement of the N-methyl-D-aspartate (NMDA) receptors in the reinstatement of extinguished morphine conditioned place preference (CPP) in rats. We found that previously extinguished morphine (3 mg/kg, i.p.) CPP was markedly reinstated by a priming injection of morphine (2 mg/kg, i.p.) or an acute environmental stressor (forced swim for 10 min), but not by the stress induced by a 24-h food deprivation. Parallel with this, protein levels of the NMDA receptor 2B subunit (NR2B) were elevated in the nucleus accumbens (NAc) and the hippocampus, but not the prefrontal cortex, of reinstated rats. Systemic administration of an NR2B selective antagonist ifenprodil (1, 3, 10 mg/kg, i.p.) attenuated the reinstatement induced by a priming morphine injection, although not by the forced swim. Ifenprodil (2.0 microg/rat) directly injected into the NAc shell or the CA1 region of the dorsal hippocampus produced a similar effect. These results indicate that the NR2B-containing NMDA receptors in the NAc and the dorsal hippocampus play a significant role in mediating the reinstatement of rewarding responses to morphine.

Topics: Amygdala; Animals; Conditioning, Operant; Excitatory Amino Acid Antagonists; Extinction, Psychological; Food Deprivation; Hippocampus; Immunoblotting; Male; Microinjections; Morphine; Morphine Dependence; Narcotics; Piperidines; Prefrontal Cortex; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Recurrence; Reward; Stress, Psychological; Swimming

JDTic, (3R)-7-hydroxy-N-[(1S)-1-{[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl]-2-methylpropyl]-1,2,3,4-tetrahydro-3-isoquinoline-carboxamide, is a potent and selective kappa-opioid antagonist with a very long duration of action [Carroll, F.I., Thomas, J.B., Dykstra, L.A., Granger, A.L., Allen, R.M., Howard, J.L., Pollard, G.T., Aceto, M.D., Harris, L.S., 2004. Pharmacological properties of JDTic: A novel k-opioid receptor antagonist. Eur. J. Pharmacol. 501, 111-119.]. When given 24 h prior to a continuous 4-day infusion of morphine sulfate in rats, JDTic did not prevent the stereotypy that developed during the infusion of morphine. It had no effect on the dramatic loss of body weight associated with the abrupt withdrawal of morphine. However, it decreased the number of important withdrawal signs designated wet-dog shakes and facial rubs. These data suggest that JDTic may find some application in the treatment of opiate abuse.

Topics: Animals; Behavior, Animal; Body Weight; Infusion Pumps; Injections, Intraperitoneal; Male; Models, Animal; Morphine; Morphine Dependence; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, Opioid, kappa; Substance Withdrawal Syndrome; Tetrahydroisoquinolines; Time Factors

The influence of the endocannabinoid system on the sensitisation to the rewarding effects of morphine in the place conditioning paradigm was evaluated. In mice pretreated with morphine this drug induces place preference with lower doses. Pretreatment with non-rewarding doses of the cannabinoid agonist WIN 55,212-2 (0.5 and 1 mg/kg) induces sensitisation to the rewarding effects of morphine. However, the pretreatment with the cannabinoid antagonist SR 144716A plus morphine or WIN 55,212-2 blocks it. Our results suggest the existence of cross-talk between cannabinoids and opiates on the sensitisation to morphine and the implication of the endocannabinoid system in the process of sensitisation to opiates.

Topics: Animals; Behavior, Animal; Benzoxazines; Brain; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Cannabinoid Receptor Modulators; Cannabinoids; Dose-Response Relationship, Drug; Drug Interactions; Male; Mice; Morphine; Morphine Dependence; Morpholines; Naphthalenes; Piperidines; Pyrazoles; Receptors, Cannabinoid; Reward; Rimonabant; Spatial Behavior

Drug addiction poses serious social, medical, and economic problems, but effective treatments for drug addiction are still limited. Cocaine and morphine elevate dopamine levels in the nucleus accumbens (NAc), and the overwhelming actions of dopamine are implicated in reinforcement and addiction of abusive drugs. In our previous studies, we reported the regulatory role of acetylcholine (ACh) in the NAc function by selectively ablating the NAc cholinergic neurons with use of immunotoxin-mediated cell targeting. These studies indicated that ACh and dopamine acted convergently but oppositely on the NAc circuit and that cholinergic cell ablation enhanced long-lasting behavioral changes of cocaine addiction. In this investigation, we showed that immunotoxin-mediated ablation of the NAc cholinergic neurons enhanced not only the sensitivity to morphine in conditioned place preference but also negative reinforcement of morphine withdrawal in conditioned place aversion. Remarkably, acetylcholinesterase (AChE) inhibitors that act on the brain AChE suppressed both cocaine- and morphine-induced conditioned place preference and blocked the induction and persistence of cocaine-evoked hyperlocomotion. Importantly, this inhibition was abolished by ablation of the NAc cholinergic neurons. These results demonstrate that centrally active AChE inhibitors prevent long-lasting behavioral abnormalities associated with cocaine and morphine addictions by potentiating the actions of ACh released from the NAc cholinergic neurons. Centrally active AChE inhibitors could thus be approached as novel and potential therapeutic agents for drug addiction.

Topics: Acetylcholine; Animals; Cholinesterase Inhibitors; Cocaine; Cocaine-Related Disorders; Conditioning, Psychological; Donepezil; Indans; Male; Mice; Mice, Inbred C57BL; Morphine; Morphine Dependence; Nucleus Accumbens; Pain; Piperidines; Substance Withdrawal Syndrome

In our studies of the development of a novel class of selective estrogen receptor modulators, (+)-3-[4-(1-piperidinoethoxy)phenyl]spiro[indene-1,1'-indane]-5,5'-diol hydrochloride (1) was found to be an estrogen receptor ligand with beneficial effects in rat models for human hot flush. Moreover, 1 was found to have beneficial effects on lipid and bone metabolism while maintaining marginal effects on the uterus and breasts. These findings suggest that 1 would provide a new treatment for hot flush.

Topics: Animals; Bone Density; Breast Neoplasms; Cholesterol; Drug Evaluation, Preclinical; Estradiol; Female; Hot Flashes; Indans; Male; Morphine Dependence; Naloxone; Piperidines; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Selective Estrogen Receptor Modulators; Skin Temperature; Spiro Compounds; Stereoisomerism; Tumor Cells, Cultured; Uterus

Chronic treatment with opioid drugs such as morphine leads to the development of tolerance, which manifests as a loss of drug potency. The mechanisms underlying this phenomenon are poorly understood, but recent evidence suggests that increased activity of nociceptive sensory transmitters [calcitonin gene-related peptide (CGRP) and substance P] and other signalling messengers (prostaglandins) contribute to its development. Chronic intrathecal morphine administration to rats for 7 days produced analgesic tolerance. Co-administration of SR140333, a selective substance P receptor (neurokinin-1) antagonist, or nimesulide, a cyclooxygenase-2-selective inhibitor, augmented the acute effects of morphine, prevented morphine tolerance and reversed established tolerance. In cultured adult dorsal root ganglion neurons, exposure to morphine for 5 days increased the number of neurons expressing CGRP immunoreactivity. Co-exposure with the peptide CGRP receptor antagonist CGRP8-37, SR140333 or nimesulide prevented the morphine-induced increase in the expression of CGRP immunoreactivity. Additionally, BIBN4096BS, a nonpeptide CGRP receptor antagonist, stereoselectively produced similar effects. In summary, this investigation demonstrates that activity of CGRP and substance P contributes to both the induction and expression of opioid analgesic tolerance. Additionally, it highlights the involvement of prostaglandins generated by spinal cyclooxygenase-2 activity in the genesis of opioid tolerance. The neuropeptide and prostanoid activity contributing to tolerance is expressed at the level of the primary afferents terminating in the spinal cord. The combination of opioids with agents that block this activity may represent a useful strategy for the prevention as well as the reversal of clinical opioid tolerance.

Topics: Animals; Behavior, Animal; Calcitonin Gene-Related Peptide; Calcitonin Gene-Related Peptide Receptor Antagonists; Cell Count; Cells, Cultured; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Interactions; Drug Tolerance; Ganglia, Spinal; Immunohistochemistry; Male; Morphine; Morphine Dependence; Neurokinin-1 Receptor Antagonists; Neurons; Pain Measurement; Piperidines; Prostaglandins; Quinuclidines; Rats; Rats, Sprague-Dawley; Receptors, Calcitonin Gene-Related Peptide; Receptors, Neurokinin-1; Spinal Cord; Sulfonamides; Time Factors

The present study was designed to explore the relationship between the cannabinoid and opioid receptors in animal models of opioid-induced reinforcement. The acute administration of SR141716A, a selective central cannabinoid CB1 receptor antagonist, blocked heroin self-administration in rats, as well as morphine-induced place preference and morphine self-administration in mice. Morphine-dependent animals injected with SR141716A exhibited a partial opiate-like withdrawal syndrome that had limited consequences on operant responses for food and induced place aversion. These effects were associated with morphine-induced changes in the expression of CB1 receptor mRNA in specific nuclei of the reward circuit, including dorsal caudate putamen, nucleus accumbens, and septum. Additionally, the opioid antagonist naloxone precipitated a mild cannabinoid-like withdrawal syndrome in cannabinoid-dependent rats and blocked cannabinoid self-administration in mice. Neither SR141716A nor naloxone produced any intrinsic effect on these behavioral models. The present results show the existence of a cross-interaction between opioid and cannabinoid systems in behavioral responses related to addiction and open new strategies for the treatment of opiate dependence.

Topics: Animals; Avoidance Learning; Cannabinoids; Caudate Nucleus; Conditioning, Operant; Disease Models, Animal; Heroin; Heroin Dependence; Male; Mice; Morphine; Morphine Dependence; Naloxone; Narcotic Antagonists; Nucleus Accumbens; Piperidines; Putamen; Pyrazoles; Rats; Rats, Wistar; Receptors, Cannabinoid; Receptors, Drug; Receptors, Opioid; Rimonabant; RNA, Messenger; Self Administration; Septum of Brain

The goal of the present study was to elucidate the relationship between cannabinoid and opioid systems in drug dependence. The CB(1) cannabinoid receptor antagonist SR 141716A precipitated both paw tremors and head shakes in four different mouse strains that were treated repeatedly with Delta(9)-tetrahydrocannabinol (Delta(9)-THC). SR 141716A-precipitated Delta(9)-THC withdrawal was ameliorated in mu-opioid receptor knockout mice compared with the wild-type control animals and failed to occur in mice devoid of CB(1) cannabinoid receptors. An acute injection of morphine in Delta(9)-THC-dependent mice undergoing SR 1417161A-precipitated withdrawal dose dependently decreased both paw tremors, antagonist dose 50 (AD(50)) (95% CL) = 0.035 (0.03--0.04), and head shakes, AD(50) (95% CL) = 0.07 (0.04--0.12). In morphine-dependent mice, the opioid antagonist naloxone precipitated head shakes, paw tremors, diarrhea, and jumping. As previously reported, naloxone-precipitated morphine withdrawal failed to occur in mu-opioid knockout mice and was significantly decreased in CB(1) cannabinoid receptor knockout mice. Acute treatment of Delta(9)-THC in morphine-dependent mice undergoing naloxone-precipitated withdrawal blocked paw tremors, AD(50) (95% CL) = 0.5 (0.3--1.0), and head shakes AD(50) (95% CL) = 0.6 (0.57--0.74) in dose-dependent manners, but failed to diminish the occurrence of diarrhea or jumping. Finally, naloxone and SR 141716A failed to elicit any overt effects in Delta(9)-THC-dependent and morphine-dependent mice, respectively. These findings taken together indicate that the mu-opioid receptor plays a modulatory role in cannabinoid dependence, thus implicating a reciprocal relationship between the cannabinoid and opioid systems in dependence.

Topics: Animals; Behavior, Animal; Cannabinoids; Diarrhea; Dronabinol; Drug Implants; Hallucinogens; Male; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Inbred ICR; Mice, Knockout; Morphine; Morphine Dependence; Narcotics; Opioid Peptides; Piperidines; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Receptors, Opioid, mu; Rimonabant; Substance Withdrawal Syndrome

The role of the cannabinoid system in morphine withdrawal was examined through long-term CB1 receptor antagonist administration in morphine pellet implanted rats. SR141716A chronic treatment (5mg/kg i.p. twice a day for four days) did not influence the development of tolerance to the morphine analgesic effect but significantly reduced the intensity of naloxone-induced opiate withdrawal in tolerant rats: Specifically there was a significant reduction in the number of digging, teeth chattering and penile licking and the incidence of diarrhoea while other signs such as writhing, head dog shakes and rearing were unaffected. These results suggest that the pharmacological treatment with SR141716A could be of some interest in ameliorating opiate withdrawal syndrome.

Topics: Analysis of Variance; Animals; Cannabinoids; Dogs; Drug Interactions; Drug Tolerance; Male; Morphine; Morphine Dependence; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptors, Cannabinoid; Receptors, Drug; Rimonabant; Substance Withdrawal Syndrome

The tolerance and dependence after chronic medication with morphine are thought to be representative models for studying the plasticity, including the remodeling of neuronal networks. To test the hypothesis that changes in neuronal plasticity observed in opioid tolerance or dependence are derived from increased activity of the anti-opioid nociceptin system, the effects of chronic treatments with morphine were examined using nociceptin receptor knock-out (NOR(-/-)) mice and a novel nonpeptidic NOR antagonist, J-113397, which shows a specific and potent NOR antagonist activity in in vitro [(35)S]GTPgammaS binding assay and in vivo peripheral nociception test. The NOR(-/-) mice showed marked resistance to morphine analgesic tolerance without affecting morphine analgesic potency in tail-pinch and tail-flick tests. The NOR(-/-) mice also showed marked attenuation of morphine-induced physical dependence, manifested as naloxone-precipitated withdrawal symptoms after repeated morphine treatments. Similar marked attenuation of morphine tolerance was also observed by single subcutaneous (10 mg/kg) or intrathecal (1 nmol) injection of J-113397, which had been given 60 min before the test in morphine-treated ddY mice. However, the intracerebroventricular injection (up to 3 nmol) did not affect the tolerance. On the other hand, morphine dependence was markedly attenuated by J-113397 that had been subcutaneously given 60 min before naloxone challenge. There was also observed a parallel enhancement of NOR gene expression only in the spinal cord during chronic morphine treatments. Together, these findings suggest that the spinal NOR system develops anti-opioid plasticity observed on morphine tolerance and dependence.

Topics: Animals; Benzimidazoles; Binding, Competitive; Brain; Cell Membrane; Disease Models, Animal; Drug Administration Schedule; Drug Antagonism; Drug Tolerance; Guanosine 5'-O-(3-Thiotriphosphate); Male; Mice; Mice, Knockout; Morphine; Morphine Dependence; Naloxone; Narcotic Antagonists; Neuronal Plasticity; Nociceptin; Nociceptin Receptor; Opioid Peptides; Pain Measurement; Piperidines; Receptors, Opioid; Spinal Cord; Substance Withdrawal Syndrome

Recent reports have provided evidence of a link between the endogenous brain cannabinoid system and the endogenous central opioid systems. Here we report that the selective CB1 receptor antagonist SR 141716A induced behavioral and endocrine alterations associated with opiate withdrawal in morphine-dependent animals in a dose-dependent manner and that naloxone induced an opiate withdrawal syndrome in animals made cannabinoid-dependent by repeated administration of the potent cannabinoid agonist HU-210. Additionally CB1 and mu-opioid receptor mRNAs were co-localized in brain areas relevant for opiate withdrawal such as the nucleus accumbens, septum, dorsal striatum, the central amygdaloid nucleus and the habenular complex. These results suggest that CB1 cannabinoid receptors may play a role in the neuroadaptive processes associated with opiate dependence, and they lend further support for the hypothesis of a potential role of cannabinoid receptors in the neurobiological changes that culminate in drug addiction.

Topics: Animals; Brain Chemistry; Gene Expression; In Situ Hybridization; Male; Morphine Dependence; Naloxone; Narcotic Antagonists; Piperidines; Pyrazoles; Rats; Rats, Wistar; Receptors, Cannabinoid; Receptors, Drug; Receptors, Opioid, mu; Rimonabant; RNA, Messenger; Substance Withdrawal Syndrome

A quasi-morphine withdrawal syndrome (QMWS), produced in opiate-naive rats with an injection of isobutylmethylxanthine (IBMX) and the opioid antagonist naloxone, allows one to study the expression of opiate withdrawal in the absence of the acute or chronic effects of opiates and the adaptive processes termed dependence. The allegedly selective and long-acting serotonin2 (5-HT2) antagonist ritanserin attenuated the QMWS-induced suppression of fixed ratio (FR) operant responding, which is a sensitive measure of the expression of a QMWS. When administered 30 min prior to precipitation of the QMWS, the lowest dose of ritanserin tested (0.158 mg/kg) was the most effective in blocking the expression of withdrawal; however, there was not complete reversal of the behavioral suppression. Acutely, the two higher doses of ritanserin tested (2.5 and 10 mg/kg) suppressed responding when given alone. This may have masked their ability to attenuate a QMWS. At a dose of 2.5 mg/kg, ritanserin completely blocked the QMWS-induced suppression of responding 24 h post-administration, at a time when its actions at other receptors (e.g., alpha 2) have dissipated. At an equivalent dose, the shorter-acting 5-HT2 antagonist mianserin was unable to attenuate the QMWS-induced suppression of FR operant responding 24 h post-administration. The 5-HT2 antagonists reportedly produce a paradoxical down-regulation of 5-HT2 binding sites upon chronic treatment, rather than the expected supersensitivity. Chronic treatment with ritanserin (2.5 mg/kg/day for 7 days), but not mianserin (same regimen), attenuated a QMWS 24 h after the final injection, thus supporting with a functional measure, the down-regulation of such binding sites by ritanserin.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 1-Methyl-3-isobutylxanthine; Animals; Conditioning, Operant; Male; Mianserin; Morphine Dependence; Naloxone; Piperidines; Rats; Reinforcement Schedule; Ritanserin; Serotonin Antagonists; Substance Withdrawal Syndrome

Topics: Adult; Dose-Response Relationship, Drug; Humans; Male; Morphine Dependence; Narcotic Antagonists; Piperidines; Substance-Related Disorders

The involvement of serotonin2 (5-HT2) receptors in the expression of opiate withdrawal was examined using a behavioral test for acute morphine dependence. The 5-HT2 antagonists, ketanserin and pirenperone, injected shortly before naloxone, attenuated the naloxone-induced suppression of an autoshaped lever-touch response in rats treated 4 h earlier with a moderate dose of morphine. A low dose of pirenperone was also effective in blocking withdrawal-induced hypothermia. These data support the hypothesis that 5-HT is involved in the expression of opiate withdrawal.

Topics: Animals; Body Temperature; Conditioning, Operant; Ketanserin; Male; Morphine Dependence; Piperidines; Rats; Rats, Inbred Strains; Substance Withdrawal Syndrome

The mixed agonist-antagonist analgesics buprenorphine, butorphanol, nalbuphine, pentazocine and picenadol were compared to the prototype mu and kappa agonists morphine and Mr 2033, respectively, in the following tests in rhesus monkeys: overt behavioral effects upon acute administration in drug-naive animals; discriminative stimulus properties in monkeys trained to respond to either etorphine or ethylketazocine; self-administration of the test agent relative to codeine; single dose suppression and precipitation in withdrawn and non-withdrawn morphine-dependent monkeys, respectively; and primary addiction studies in drug-naive animals. Whereas both buprenorphine and nalbuphine precipitate withdrawal in morphine-dependent monkeys, withdrawal following chronic administration of buprenorphine resulted in no observable signs of abstinence, while nalbuphine withdrawal was similar to that seen in morphine-dependent monkeys. Butorphanol, pentazocine and picenadol all produced mild dependence of the kappa-type; that is, natural withdrawal behavior similar to that seen following chronic Mr 2033 administration.

Topics: Animals; Behavior, Animal; Benzomorphans; Buprenorphine; Butorphanol; Codeine; Discrimination, Psychological; Humans; Macaca mulatta; Morphinans; Morphine; Morphine Dependence; Nalbuphine; Narcotic Antagonists; Pentazocine; Piperidines; Substance Withdrawal Syndrome

Prostaglandins and cyclic adenosine monophosphate have been claimed to play a major role in the morphine withdrawal syndrome, but intestinal secretion has not been ruled out as being responsible, at least in part, for the accompanying diarrhea. Therefore, experiments were performed in which the effect of naloxone-induced morphine withdrawal on jejunal and on colonic fluid transport was assessed in tied-off loops of rat intestine in vivo simultaneously with mucosal cyclic adenosine monophosphate levels or colonic luminal release of prostaglandin E2 or 5-hydroxytryptamine. Naloxone-induced withdrawal reversed fluid absorption to secretion without changing cyclic adenosine monophosphate levels, but markedly enhanced local prostaglandin E2 and 5-hydroxytryptamine release (p less than 0.01). Indomethacin and the 5-hydroxytryptamine receptor antagonist ketanserin prevented withdrawal-induced fluid secretion and the increase in prostaglandin E2 release without influencing the release of 5-hydroxytryptamine. In addition, the alpha 2-adrenergic receptor agonist clonidine promoted absorption during withdrawal, whereas atropine failed to influence fluid transport. These data suggest that naloxone-precipitated intestinal fluid secretion may contribute to diarrhea due to morphine withdrawal and that 5-hydroxytryptamine may play an important role in mediating this secretion through stimulation of local prostaglandin formation.

Topics: Animals; Atropine; Clonidine; Colon; Cyclic AMP; Diarrhea; Dinoprostone; Female; Humans; Indomethacin; Ketanserin; Morphine Dependence; Naloxone; Piperidines; Prostaglandins E; Rats; Rats, Inbred Strains; Serotonin; Substance Withdrawal Syndrome

The N-(2-cyanoethyl)-9alpha-ethyl-5-methyl-6,7-benzomorphan (1c) is a more potent antinociceptive and has stronger receptor binding affinity than its N-methyl analogue 1b. The N-(2-cyanoethyl)-4-phenylpiperidine compounds 2b and 3b were almost inactive compared to their N-methyl congeners 2a and 3a, respectively. It appears that the pharmacological effect of the N-(2-cyanoethyl) moiety is dependent on the opioid on which it is substituted.

Topics: Analgesics; Animals; Benzomorphans; Binding, Competitive; Brain; Dihydromorphine; Haplorhini; Humans; In Vitro Techniques; Macaca mulatta; Meperidine; Mice; Morphinans; Morphine Dependence; Nitriles; Piperidines; Rats; Structure-Activity Relationship

A single administration of ifenprodil at the doses of 100, 200 and 400 mg/kg (p.o.), and 50 and 100 mg/kg (i.m.) produced a moderate CNS depression in rats, such as, sedation, ptosis, systemic muscle relaxation and decrease in motor activity. These symptoms appeared dose-dependently and persisted for about 4 hours following administration. In a direct physical dependence test, 5 groups of rats were fed the ifenprodil-admixed food together with drinking water ad libitum for 24 hours daily for 53 approximately 103 days (mean ifenprodil intake, 43--240 mg/kg/day), on the gradedly increased dosage schedule with a dosage level of 0.5 vs. 1 mg/g food to 4 mg/g food. In the natural withdrawal following administration, no significant withdrawal signs were observed in any group. In a substitution test either for phenobarbital or morphine, no suppression of withdrawal signs during the period of cross-administration of ifenprodil and no maintenance of dependence were observed. In a physical dependence-producing test, the rats fed ifenprodil never manifested withdrawal signs such as diarrhea, "wet shakes", sudden loss of body weight as in the levallorphan precipitation test. Ifenprodil apparently has no physical dependence liability.

Topics: Animals; Body Weight; Central Nervous System; Depression, Chemical; Dose-Response Relationship, Drug; Eating; Humans; Isoxsuprine; Levallorphan; Male; Morphine Dependence; Piperidines; Rats; Substance Withdrawal Syndrome; Substance-Related Disorders; Time Factors

Topics: Animals; Guinea Pigs; Haplorhini; Humans; Ileum; In Vitro Techniques; Isomerism; Kinetics; Morphine Dependence; Narcotic Antagonists; Piperidines; Stereoisomerism; Structure-Activity Relationship

Topics: Alkylation; Analgesics; Animals; Chemical Phenomena; Chemistry; Esters; Female; Haplorhini; Humans; Male; Mice; Mice, Inbred Strains; Morphine; Morphine Dependence; Narcotic Antagonists; Phenols; Piperidines; Reflex; Structure-Activity Relationship; Substance-Related Disorders; Tail

Topics: Acetamides; Amphetamine; Animals; Antihypertensive Agents; Behavior, Animal; Brain; Butyrophenones; Dopamine; Humans; Male; Methyltyrosines; Morphine Dependence; Norepinephrine; Phenoxybenzamine; Piperidines; Rats; Reserpine; Spiro Compounds; Thiocarbamates; Tranquilizing Agents

Topics: Analgesics; Drug and Narcotic Control; Health Education; Heroin; Humans; Morphine Dependence; Piperidines; Substance-Related Disorders; United Kingdom; World Health Organization