Modification of the antinociceptive effect of morphine by centrally administered diazepam and midazolam.
1 Intracerebroventricular administration of diazepam or midazolam decreased the antinociceptive effect of morphine in rats as measured by the "tail flick" method. 2 Midazolam, injected into the periaqueductal grey matter (PAG) antagonized the analgesic effect of morphine. The action of midazolam was partially reversed by bicuculline. 3 These findings support the view that the effect of benzodiazephines on morphine antinociception may be mediated through gamma-aminobutyric acid receptors.
D000700:Analgesics / Q000037:antagonists & inhibitors*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001569:Benzodiazepines / Q000494:pharmacology*; D001640:Bicuculline / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D008874:Midazolam; D009020:Morphine / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D000700:Analgesics; D014151:Anti-Anxiety Agents; D001569:Benzodiazepines; D009020:Morphine; D003975:Diazepam; D008874:Midazolam; D001640:Bicuculline