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Effect of the Opioid Peptide Beta-Endorphin on the in vivo Release of Vasopressin in Rats under Various Conditions

1986; Karger Publishers; Volume: 44; Issue: 1 Linguagem: Inglês

10.1159/000124629

1423-0194

Jeroen A. Ten Haaf, Tjeerd B. Van Wimersma Greidanus, Carla Maigret, D. de Wied,

Stress Responses and Cortisol

β-Endorphin (βE) 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 βE to HIS treatment, βE partially prevents the increase of plasma VP levels. Naloxone subcutaneously administered, antagonizes the effect of βE in all the situations we investigated. Opioid receptors, located in the brain as well as in the pituitary, are possibly involved in these processes.