ISSN:
1432-2072
Keywords:
Cannabis
;
Catecholamines
;
Antinociception
;
6-Hydroxydopamine
;
Narcotic antagonists
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract An extract of cannabis (5 and 15 mg/kg expressed as Δ9-THC) orally administered to rats caused an elevation of the nociceptive threshold (tail-flick latency and vocalization tests). Naloxone and naltrexone (blockers of μ-type opiate receptors) as well as MR 1452 (blocker of κ opiate receptors) did not prevent the antinociceptive effect of cannabis when used at the dose of 2 mg/kg SC; only a high dose (10 mg/kg SC) of these narcotic antagonists partially blocked cannabis antinociception. ICI 154, 129, an antagonist of δ-type opiate receptors, failed to prevent the cannabis-induced rise in nociceptive threshold when used at a dose of 2 mg/kg SC but produced a significant effect at 10 mg/kg SC. While the role of opiate receptors does not seem fundamental to cannabis antinociception, the clear-cut effectiveness shown by 6-hydroxydopamine (a neurotoxin which causes a degeneration of catecholamine-containing terminals) in reducing cannabis antinociception is indicative of a participation of catecholamines in the phenomenon.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00310637
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