Possible involvement of 5-hydroxytryptamine and cyclic-AMP in tolerance to tremorine analgesia in mice.
The phenomenon of tolerance to the analgesic action of tremorine in mice was studied by the hot-plate and tail-clip methods. Reduction in 5-HT levels in brain by parachlorophenylalamine pretreatment decreased the ED50 of tremorine analgesia in tremorine tolerant mice. 5-Hydroxyptophan, L-Dopa or alpha-methyl-para-tyrosine did not influence the analgesic response to tremorine in tremorine tolerant animals. However, theophylline was found to enhance the tolerance to tremorine analgesia. Brain 5-HT and cAMP are probably involved in tremorine tolerance, whereas neither noradrenaline nor dopamine is involved in the phenomenon.
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000700:Analgesics; D000818:Animals; D000242:Cyclic AMP / Q000502:physiology*; D004347:Drug Interactions; D004361:Drug Tolerance; D010134:Fenclonine / Q000494:pharmacology; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D051379:Mice; D012701:Serotonin / Q000502:physiology*; D013806:Theophylline / Q000494:pharmacology; D013997:Time Factors; D014203:Tremorine / Q000494:pharmacology*
D000700:Analgesics; D008781:Methyltyrosines; D012701:Serotonin; D007980:Levodopa; D013806:Theophylline; D006916:5-Hydroxytryptophan; D000242:Cyclic AMP; D010134:Fenclonine; D014203:Tremorine