piperidines and (2-methoxy-5-tetrazol-1-ylbenzyl)(2-phenylpiperidin-3-yl)amine

Mu-, kappa- and delta-opioid receptor agonists are reported to attenuate the acetic-acid-induced abdominal constriction response in mice. NK-1, -2 and -3 receptor antagonists also display activity in several visceral pain models. As the gerbil NK-1 receptor is comparable to the human receptor, we evaluated the efficacy of NK-1, -2 and -3 receptor antagonists and opioids (both alone and in combination) in the writhing test in this species. The effects of a selective L-type calcium (Ca2+) channel antagonist on the writhing response were also assessed to determine the contribution of Ca2+ channel antagonism to the antinociceptive effects of the NK-1 antagonists. Gerbils received subcutaneous injections of either the mu-opioids morphine or fentanyl, the kappa-opioid U50,488-H, the delta-opioid SNC80, NK-1 antagonists R116301, CP-96,345 or GR203040, the NK-2 antagonist SR-48968, the NK-3 antagonist SR-142801 or the Ca2+ channel antagonist nimodipine. Writhing was evoked 1 h after treatment by intraperitoneal injection of 0.2 ml 1% acetic acid solution and the frequency was recorded. Morphine, fentanyl and U50,488-H attenuated the writhing response dose dependently with complete inhibition occurring at the highest doses. SNC80 did not significantly attenuate the writhing response even at a dose of 40 mg/kg. The tachykinin NK-1 antagonists CP-96,345 and GR203040, the NK-2 antagonist SR-48968 and the NK-3 antagonist SR-142801 reduced the writhing frequency although without complete inhibition. The NK-1 antagonist R116301 displayed limited activity at doses up to 40 mg/kg. Nimodipine did not exhibit any antinociceptive efficacy in this assay. Adding the NK-1, -2 or -3 antagonists to the opioids did not improve the efficacy of the opioids. Selective NK antagonists may therefore be effective in a visceral nociception assay in gerbils but do not modulate opioid action.

Topics: 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; Abdomen; Acetic Acid; Analgesics, Opioid; Animals; Behavior, Animal; Biphenyl Compounds; Butanols; Calcium Channel Blockers; Dose-Response Relationship, Drug; Female; Fentanyl; Gerbillinae; Malates; Morphine; Muscle Contraction; Neurokinin-1 Receptor Antagonists; Pain Measurement; Piperidines; Receptors, Neurokinin-2; Receptors, Neurokinin-3; Receptors, Opioid, delta; Receptors, Opioid, kappa; Receptors, Opioid, mu; Tetrazoles

Two high affinity and selective NK1-receptor antagonists, GR203040 and GR205171, were labelled with 11C and used in a series of experiments in rhesus monkeys. The purpose of these studies was to evaluate the brain uptake pattern and to explore the potential use of these compounds as PET ligands to characterise NK1-receptor binding. Seventeen studies were carried out with [11C]GR205171 and five experiments with [11C]GR203040, including baseline studies and studies performed after a 5 min infusion of cold compound at doses between 0.05 and 1 mg/kg. Both compounds demonstrated a significant and rapid uptake in the brain, but the uptake of [11C]GR205171 was more than double the uptake of [11C]GR203040. At tracer doses of [11C]GR205171 and all doses of [11C]GR203040 the uptake reached a plateau with no washout during the examination time, whereas [11C]GR205171 after pre-treatment with cold GR205171 showed a significant washout. Using a model with the cerebellum as reference, a method for quantitation was applied to the studies with [11C]GR205171 and the results indicated that the highest specific binding was in the striatum. The pre-treatment dose of cold GR205171 needed for 50% inhibition of binding was less than 0.04 mg/kg. The studies indicated that [11C]GR205171 could be used for the in vivo characterisation of NK1-receptor binding.

Topics: Animals; Brain; Carbon Radioisotopes; Ligands; Macaca mulatta; Neurokinin-1 Receptor Antagonists; Piperidines; Protein Binding; Receptors, Neurokinin-1; Tetrazoles; Tomography, Emission-Computed

1. The effects of GR203040, a tachykinin neurokinin1 receptor antagonist, on tissue damage induced by X-irradiation (Rad) or cisplatin (Cisp) were investigated in ferrets. 2. GR203040 (0.3 mg/kg SC) reduced the Rad-induced plasma protein extravasation (PPE) in the duodenum and kidney by 25% in each tissue. 3. GR203040 (3 mg/kg SC, 5-min pretreatment and every 8 hr for 48 hr after Cisp) reduced the Cisp-induced PPE in the duodenum, jejunum and lung by 59, 52 and 60%, respectively. 4. Histological examination showed that GR203040 also ameliorated the Rad- and Cisp-induced tissue damage.

Topics: Animals; Antiemetics; Antineoplastic Agents; Capillary Permeability; Cisplatin; Duodenum; Ferrets; Histocytochemistry; Jejunum; Kidney; Lung; Male; Neurokinin-1 Receptor Antagonists; Piperidines; Tetrazoles; Urinary Bladder; Whole-Body Irradiation

1. The effect of the tachykinin neurokinin1 (NK1) receptor antagonist GR203040 on cyclophosphamide (CYP)-induced bladder damage was investigated in rats and ferrets. The 5-hydroxytryptamine3 receptor antagonists ondansetron and granisetron were similarly examined in ferrets. 2. In the rat, GR203040 (10 and 30 mg/kg i.p.) reduced the CYP-induced plasma protein extravasation in the bladder by 44% and 73%, respectively (P < 0.05 and 0.005; cf. CYP controls); in the ferret, a 57% reduction (P < 0.005) was observed after GR203040 (0.3 mg/kg SC). No decrease was observed in ferrets with either ondansetron or granisetron (1 mg/kg SC). 3. GR203040 attenuated the CYP-induced damage in the rat and ferret bladder, at the same dose in the ferret previously shown to inhibit CYP-induced emesis.

Topics: Animals; Blood Proteins; Cyclophosphamide; Ferrets; Male; Neurokinin-1 Receptor Antagonists; Piperidines; Rats; Rats, Wistar; Tetrazoles; Urinary Bladder

It has been demonstrated recently that antagonists of the tachykinin NK1 receptor, specifically CP-99,994 and GR203040, possess anti-emetic activity in a range of species. To optimise this activity, a series of analogues based around the structure of GR203040 have been synthesised and their affinity at the human tachykinin NK1 receptor determined. In addition, the potency of these analogues to inhibit emesis induced in the ferret by whole-body X-irradiation has been examined. A range of substitution at the C-1 position of the tetrazole moiety in GR203040 were explored in vitro and in vivo. The trifluoromethyl compound, GR205171, was the most potent antagonist with regard to the ability to inhibit emesis induced by X-irradiation. This compound was demonstrated to have a broad spectrum of anti-emetic activity, inhibiting emesis in the ferret induced by cisplatin, cyclophosphamide, morphine, ipecacuanha and copper sulphate. Furthermore, emesis was also inhibited in the house-musk shrew, Suncus murinus, when induced by either motion or cisplatin, and in the dog when induced by ipecacuanha. GR205171 has the most potent anti-emetic activity of any tachykinin NK1 receptor antagonist described to date. The compound is orally active in the ferret and dog, long-lasting, and warrants further investigation as a potential broad-spectrum anti-emetic agent.

Topics: Administration, Oral; Animals; Antiemetics; Cisplatin; Dogs; Dose-Response Relationship, Drug; Ferrets; Humans; Male; Motor Activity; Neurokinin-1 Receptor Antagonists; Piperidines; Receptors, Neurokinin-1; Shrews; Stereoisomerism; Tetrazoles

The antiemetic, pharmacokinetic, and metabolic profile of CP-99,994, a potent NK1 receptor antagonist, has been carefully evaluated. As a result we began a medicinal chemistry program which initially identified a 3-furanyl analogue (6) with improved antiemetic potency and a methyl sulfone (5) with enhanced metabolic stability and oral bioavailability. The improved pharmacokinetic profile of methyl sulfone (5) was associated with its low lipophilicity, and a therefore a number of heterocyclic analogues with reduced log D were synthesized. Out of this program emerged 19 (GR203040), a tetrazolyl-substituted analogue. Tetrazole 19 inhibits radiation-induced emesis in the ferret with high potency when administered both subcutaneously and orally, has a long duration of action, and has high oral bioavailability in the dog. Tetrazole 19 is currently undergoing evaluation as a novel approach for the control of emesis associated with, for example, cancer chemotherapy.

Topics: Animals; Antiemetics; Biological Availability; Cell Membrane; CHO Cells; Cricetinae; Dogs; Female; Ferrets; Gerbillinae; Magnetic Resonance Spectroscopy; Male; Neurokinin-1 Receptor Antagonists; Piperidines; Tachykinins; Tetrazoles; Vomiting; Whole-Body Irradiation

1. The in vitro and in vivo pharmacology of GR203040 ((2S, 3S)-2-methoxy-5-tetrazol-1-yl-benzyl-(2-phenyl-piperidin-3-y l)-amine), a novel, highly potent and selective non-peptide tachykinin NK1 receptor antagonist, was investigated in the present study. 2. GR203040 potently inhibited [3H]-substance P binding to human NK1 receptors expressed in Chinese hamster ovary (CHO) and U373 MG astrocytoma cells, and NK1 receptors in ferret and gerbil cortex (pKi values of 10.3, 10.5, 10.1 and 10.1 respectively). GR203040 had lower affinity at rat NK1 receptors (pKi = 8.6) and little affinity for human NK2 receptors (pKi < 5.0) in CHO cells and NK3 receptors in guinea-pig cortex (pKi < 6.0). With the exception of the histamine H1 receptor (pIC50 = 7.5). GR203040 had little affinity (pIC50 < 6.0) at all non-NK1 receptors and ion channels examined. Furthermore, GR203040 produced only weak inhibition of Na+ currents in SH-SY5Y neuroblastoma and superior cervical ganglion cells (pIC50 values < 4.0). GR203040 produced only weak antagonism of Ca(2+)-evoked contractions of rat isolated portal vein (pKn = 4.1). The enantiomer of GR203040, GR205608 (2R, 3R)-2-methoxy-5-tetrazol-1-yl-benzyl-(2-phenyl-piperidin-3-y l)-amine), had 10,000 fold lower affinity at the human NK1 receptor expressed in CHO cells (pKi = 6.3). 3. In gerbil ex vivo binding experiments, GR203040 produced a dose-dependent inhibition of the binding of [3H]-substance P to cerebral cortical membranes (ED50 = 15 micrograms kg-1 s.c. and 0.42 mg kg-1 p.o.). At 10 micrograms kg-1 s.c., the inhibition of [3H]-substance P binding was maintained for > 6 h. In the rat, GR203040 was less potent (ED50 = 15.4 mg kg-1 s.c.) probably reflecting, at least in part, its lower affinity at the rat NK1 receptor. 4. In guinea-pig isolated ileum and dog isolated middle cerebral and basilar arteries, GR203040 produced a rightward displacement of the concentration-effect curves to substance P methyl ester (SPOMe) with suppression of the maximum agonist response (apparent pKB values of 11.9, 11.2 and 11.1 respectively). 5. In anaesthetized rabbits, GR203040 antagonized reductions in carotid arterial vascular resistance evoked by SPOMe, injected via the lingual artery (DR10 (i.e. the dose producing a dose-ratio of 10) = 1.1 micrograms kg-1, i.v.). At a dose 20 fold greater than its DR10 value (i.e. 22 micrograms kg-1, i.v.), significant antagonism was evident more than 2 h after GR203040 administration. 6. In anaesthetized rats, GR2

Topics: Animals; Binding, Competitive; Brain; Cattle; Cells, Cultured; Cerebral Arteries; CHO Cells; Cricetinae; Dogs; Ferrets; Gerbillinae; Hemodynamics; Humans; Ileum; In Vitro Techniques; Neurokinin-1 Receptor Antagonists; Piperidines; Portal Vein; Rabbits; Rats; Receptors, Neurotransmitter; Substance P; Tetrazoles; Transfection

1. Following our earlier observations that the tachykinin NK1 receptor antagonist CP-99,994 is an effective anti-emetic in ferrets, we have examined the anti-emetic effects of a more potent and novel NK1 receptor antagonist, GR203040, against various emetic stimuli in the ferret, dog and house musk shrew (Suncus murinus). 2. In ferrets, GR203040 (0.1 mg kg-1 s.c. or i.v.) is effective against emesis induced by radiation, cisplatin, cyclophosphamide, copper sulphate, ipecacuanha or morphine. 3. In animals in which emesis had been established with cisplatin, GR203040 (1 mg kg-1 s.c.) was fully effective as an interventional treatment. No further emesis was seen in animals treated with GR203040 whilst saline-treated animals continued to vomit. 4. GR203040 (0.1 mg kg-1 s.c.) retains anti-emetic efficacy in the ferret, even when given as a 6 h pretreatment, indicating that this compound has a long duration of action. The compound is also effective orally at the same dose, when given as a 90 min pretreatment. 5. GR203040 (0.1 mg kg-1 i.v.) is fully effective against ipecacuanha-induced emesis in the dog. 6. GR203040 is effective against motion- and cisplatin-induced emesis in Suncus murinus. These effects were seen at doses an order of magnitude greater than those shown to be effective against cisplatin in the ferret. 7. In conclusion, GR203040 is a novel anti-emetic agent, and the broad spectrum of anti-emetic activity, together with activity observed in three species, suggests that this compound is worthy of clinical investigation.

Topics: Animals; Antiemetics; Dogs; Dose-Response Relationship, Drug; Emetics; Ferrets; Male; Motion Sickness; Neurokinin-1 Receptor Antagonists; Piperidines; Radiation Injuries, Experimental; Shrews; Tetrazoles; Vomiting