title: Effects of beta-endorphin on norepinephrine release in hypertension.
abstract: Recent studies have suggested an involvement of the endogenous opioid system in blood pressure control. The purpose of the present study was to determine the role of beta-endorphin in the regulation of sympathetic nervous activity in the central nervous system of hypertension. The effects of beta-endorphin on the electrically evoked release of [3H]norepinephrine (NE) were investigated in superfused slices of rat medulla oblongata. Beta-endorphin inhibited the stimulation-evoked NE release in a dose-dependent manner in rat medulla oblongata. In the medulla oblongata of spontaneously hypertensive rats (SHR), the inhibitory effect of beta-endorphin on the stimulation-evoked NE release was significantly smaller than in the medulla oblongata of Wistar-Kyoto rats. These results showed that beta-endorphin might reduce NE release in rat medulla oblongata. Furthermore, the lesser inhibitory effect of beta-endorphin on NE release in SHR might suggest that the opioid peptide could be involved in the regulation of central sympathetic nervous activity in hypertension.
authors.affiliation: Department of Medicine, Wakayama Medical College, Japan. tsudak@mail.wakayama-med.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Tsuda
authors.forename: S
authors.initials: S
authors.lastname: Tsuda
authors.forename: I
authors.initials: I
authors.lastname: Nishio
authors.forename: Y
authors.initials: Y
authors.lastname: Masuyama
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D001615:beta-Endorphin / Q000494:pharmacology*
chemical_list: D001615:beta-Endorphin; D009638:Norepinephrine