Differences in central effects of beta-endorphin and enkephalins: beta-endorphin. A potent psychomotor stimulant.
The endogenous opiate-like peptides, beta-endorphin, methionine- and leucine-enkephalin have been investigated in unanaesthetized cats after intracerebroventricular injection. beta-Endorphin produced marked and prolonged psychomotor stimulation (restlessness, apprehension, looking around, vacant stare and impelling locomotion), accompanied by pupillary dilation and tremor which was prevented by nalorphine. In contrast to beta-endorphin, the enkephalins did not cause affective behavioural phenomena. However, the enkephalins evoked transient and inconsistent vomiting which was also prevented by nalorphine. It is apparent, therefore, that morphinomimetic brain peptides are involved in at least two functions in the central nervous system: beta-endorphin subserves the mediation of a long-lasting psychomotor stimulation, while the enkephalins mediate vomiting of a transient character.
D017109:Akathisia, Drug-Induced; D000818:Animals; D002415:Cats; D004723:Endorphins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004743:Enkephalin, Leucine; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D009269:Nalorphine / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects; D014839:Vomiting / Q000139:chemically induced; D001615:beta-Endorphin
D004723:Endorphins; D004745:Enkephalins; D011957:Receptors, Opioid; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; D009269:Nalorphine