Effect of apomorphine on the antinociceptive activity of morphine.
Apomorphine pretreatment potentiated the analgesic effect of morphine in a dose-dependent manner both in rats and in mice measured by five different tests (writhing, hot plate, inflamed foot, tail-pinch and tail-flick procedures). Furthermore, apomorphine augmented the antinociceptive activity of morphine in tolerant animals as well. In morphine dependent mice the nalorphine precipitated jumping--a withdrawal symptom--was found inhibited by apomorphine treatment. The results are discussed in the light of the numerous but contradictory data available in the literature.
D000701:Analgesics, Opioid; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D004357:Drug Synergism; D004361:Drug Tolerance; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009269:Nalorphine / Q000037:antagonists & inhibitors; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D013375:Substance Withdrawal Syndrome / Q000139:chemically induced / Q000503:physiopathology; D013997:Time Factors
D000701:Analgesics, Opioid; D009020:Morphine; D001058:Apomorphine; D009269:Nalorphine