title: Sigma antagonists potentiate opioid analgesia in rats.
abstract: In mice, activation of sigma1 receptors antagonizes opioid analgesia. Sigma antagonists potentiate opioid analgesia, implying that the anti-opioid sigma system is tonically active. Co-administration of haloperidol with the mu opioid morphine, the kappa 1 analgesic U50,488H or the kappa 3 agonist naloxone benzoylhydrazone enhances the analgesic activity of all agents. The effect results from sigma receptor blockade since (-)sulpiride, a selective D2 antagonist which does not block sigma receptors, is inactive.
authors.affiliation: Cotzias Laboratory of Neuro-Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
authors.forename: C C
authors.initials: CC
authors.lastname: Chien
authors.forename: G W
authors.initials: GW
authors.lastname: Pasternak
mesh_terms: D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D006220:Haloperidol / Q000494:pharmacology; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017480:Receptors, sigma / Q000037:antagonists & inhibitors*; D013469:Sulpiride / Q000494:pharmacology
chemical_list: D000700:Analgesics; D009294:Narcotics; D011759:Pyrrolidines; D017480:Receptors, sigma; D009270:Naloxone; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D009020:Morphine; D013469:Sulpiride; D006220:Haloperidol