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5‐Methoxy‐ N,N ‐dimethyltryptamine‐induced analgesia is blocked by α‐adrenoceptor antagonists in rats
Author(s) -
Archer Trevor,
Danysz Wojciech,
Jonsson Gösta,
Minor Bruce G.,
Post Claes
Publication year - 1986
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1986.tb10259.x
Subject(s) - yohimbine , phentolamine , prazosin , tail flick test , chemistry , agonist , analgesic , nociception , pharmacology , idazoxan , saline , anesthesia , endocrinology , medicine , stimulation , antagonist , receptor
1 The effects of the α‐adrenoceptor antagonists prazosin, phentolamine and yohimbine upon 5‐methoxy‐ N,N ‐dimethyltryptamine (5‐MeODMT)‐induced analgesia were tested in the hot‐plate, tail‐flick and shock‐titration tests of nociception with rats. 2 Intrathecally injected yohimbine and phentolamine blocked or attenuated the analgesia produced by systemic administration of 5‐MeODMT in all three nociceptive tests. Intrathecally administered prazosin attenuated the analgesic effects of 5‐MeODMT in the hot‐plate and tail‐flick tests, but not in the shock titration test. 3 Intrathecal yohimbine showed a dose‐related lowering of pain thresholds in saline and 5‐MeODMT‐treated animals. Phentolamine and prazosin produced normal dose‐related curves in the hot‐plate test and biphasic effects in the shock titration and tail‐flick tests. 4 These results demonstrate a functional interaction between α 2 ‐adrenoceptors and 5‐HT agonist‐induced analgesia at a spinal level in rats.