The potentiation of spinal analgesia by leucine enkephalin.
In two strains of rats, intrathecal administration of morphine and met-enkephalin was found to produce a dose-dependent analgesic effect as measured by the tail-flick assay. Prior administration of leu-enkelphalin at a dose which had no analgesic effect was found to reduce significantly the analgesic ED50 of both morphine and met-enkephalin. Met-enkephalin pretreatment, at a similar sub-analgesic dose, was without effect. Thus, a differential interaction of the enkephalins with morphine is evident at spinal structures.
D000775:Anesthesia, Spinal; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004743:Enkephalin, Leucine; D004745:Enkephalins / Q000494:pharmacology; D007278:Injections, Spinal; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011930:Reaction Time / Q000187:drug effects
D004745:Enkephalins; D004743:Enkephalin, Leucine; D009020:Morphine