Modulatory effects of morphine, U-50488H and 1,3-di-(2-tolyl)guanidine on cocaine-like discriminative stimulus in the rat using two-choice discrete-trial avoidance paradigm.

Abstract

The present study was designed to investigate the effects of the mu-opioid morphine, trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)- cyclohexyl]-benzene acetamide, methane sulfonate hydrate (U-50488H), a kappa-selective opioid receptor agonist, and 1,3-di-(2-tolyl)guanidine (DTG), sigma-receptor agonist, on the discriminative stimulus properties of cocaine in the rat trained to discriminate 10 mg/kg of cocaine from its vehicle in a shock avoidance paradigm. Morphine (1-5.6 mg/kg), U-50488H (1-10 mg/kg) or 1,3-di-(2-tolyl) guanidine (1 and 10 mg/kg) alone did not produce any stimulus effects in common with cocaine. In contrast, morphine (5.6 mg/kg) and DTG (10 mg/kg), unlike U-50488H (10 mg/kg), significantly shifted the stimulus-generalization curve for cocaine to the left. These results suggest that agonists for mu-opioid- and sigma-receptors augment the discriminative stimulus properties of cocaine.

• Authors: M Ukai, E Mori, T Kameyama
• Journal: Methods and findings in experimental and clinical pharmacology (Methods Find Exp Clin Pharmacol) Vol. 19 Issue 8 Pg. 541-6 (Oct 1997) ISSN: 0379-0355 [Print] Spain
• PMID: 9442477 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Analgesics, Non-Narcotic
• Analgesics, Opioid
• Dopamine Uptake Inhibitors
• Guanidines
• Receptors, Opioid
• 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer
• Morphine
• Cocaine
• 1,3-ditolylguanidine

Topics

• 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer (pharmacology)
• Analgesics, Non-Narcotic (pharmacology)
• Analgesics, Opioid (pharmacology)
• Analysis of Variance
• Animals
• Avoidance Learning (drug effects)
• Cocaine (toxicity)
• Discrimination Learning (drug effects)
• Dopamine Uptake Inhibitors (toxicity)
• Dose-Response Relationship, Drug
• Guanidines (pharmacology)
• Male
• Morphine (pharmacology)
• Rats
• Receptors, Opioid (agonists)