Effect of the opioid peptide beta-endorphin on the in vivo release of vasopressin in rats under various conditions.
beta-Endorphin (beta E) exerts a strong inhibitory action on plasma vasopressin (VP) of rats, after intracerebroventricular, but not after subcutaneous injection of the drug. This effect is time- and dose-dependent. Also in the water-deprived rat, this treatment leads to a strong decrease of plasma VP levels. When rats treated with histamine (HIS) intracerebroventricularly to stimulate VP levels are injected with beta E to HIS treatment, beta E partially prevents the increase of plasma VP levels. Naloxone subcutaneously administered, antagonizes the effect of beta E in all the situations we investigated. Opioid receptors, located in the brain as well as in the pituitary, are possibly involved in these processes.
D000818:Animals; D004723:Endorphins / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D008297:Male; D010904:Pituitary Gland, Posterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000097:blood / Q000378:metabolism*; D001615:beta-Endorphin
D004723:Endorphins; D014667:Vasopressins; D001615:beta-Endorphin