Opiate-like action of methionine-enkephalin in inhibiting morphine abstinence syndrome.
Intracerebroventricular administration of methionine-enkephalin or morphine sulfate immediately prior to naloxone administration inhibited the precipitated withdrawal jumping response in mice rendered dependent on morphine by the pellet implantation method. Both methionine-enkephalin and morphine sulfate failed to inhibit withdrawal defecation and rearing behavior. Morphine sulfate was found to be four times as potent as methionine-enkephalin, on molar basis, in inhibiting the abstinence syndrome. These data provide new in vivo pharmacologic evidence for the opiate-like action of methionine-enkephalin.
D000818:Animals; D006801:Humans; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology / Q000627:therapeutic use; D009270:Naloxone; D009294:Narcotics; D009842:Oligopeptides / Q000494:pharmacology* / Q000627:therapeutic use; D013239:Stereotyped Behavior / Q000187:drug effects; D013375:Substance Withdrawal Syndrome / Q000139:chemically induced / Q000517:prevention & control*
D009294:Narcotics; D009842:Oligopeptides; D009270:Naloxone; D009020:Morphine