Analgesia induced by brief footshock: blockade by fenfluramine and 5-methoxy-N,N-dimethyltryptamine and prevention of blockade by 5-HT antagonists.
Analgesia induced by footshock (2 mA, 30 s) is decreased by the 5-HT releaser, fenfluramine, and the rapidly acting 5-HT agonist, 5-methoxy-N,N-dimethyltryptamine (5-MeODMT). These decreases are blocked by the 5-HT antagonists, cyproheptadine and methiothepin. However, the antagonists when given alone do not influence shock-induced analgesia. Therefore, analgesia induced by brief footshock in the absence of drugs may not involve 5-HT-dependent mechanisms even though it may be influenced by pharmacologically provoked changes of 5-HT release or by 5-MeODMT. This drug was also able to attenuate the analgesia after its induction, possibly reflecting a disruption of memory processes rather than of nociceptive mechanisms per se.
D000818:Animals; D003533:Cyproheptadine / Q000494:pharmacology; D004597:Electroshock; D005277:Fenfluramine / Q000494:pharmacology*; D008297:Male; D011939:Mental Recall / Q000187:drug effects; D008719:Methiothepin / Q000494:pharmacology; D008732:Methoxydimethyltryptamines / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D012701:Serotonin / Q000031:analogs & derivatives*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects*
D008732:Methoxydimethyltryptamines; D012702:Serotonin Antagonists; D005277:Fenfluramine; D003533:Cyproheptadine; D012701:Serotonin; D008719:Methiothepin