The effect of atenolol, a p!-adrenergic antagonist, on nocturnal plasma melatonin secretion: Evidence for a dose-response relationship in humans

Authors


Address reprint requests to Pradeep J. Nathan, University of Melbourne, Department of Psychiatry, Austin and Repatriation Medical Centre, Heidelberg, 3084, Germany.

Abstract

Nathan PJ, Maguire KP, Burrows GD, Norman T.R. The effect of atenolol, a β1-adrenergic antagonist, on nocturnal plasma melatonin secretion: Evidence for a dose-response relationship in humans. J. Pineal Res. 1997; 23:131–135. © Munksgaard, Copenhagen

Abstract

Pineal β1-adrenergic receptors are involved in the regulation of melatonin secretion. The involvement of β1adrenergic receptors has been demonstrated by the ability of acute administration ofβ-antagonists to suppress the nocturnal rise of circulating melatonin and its urinary metabolite 6-sulphatoxymelatonin (aMT6s). The present study was undertaken to examine the relationship between increasing doses of atenolol and nocturnal plasma melatonin concentrations. Six healthy subjects participated in the study for a period of 5 weeks. Subjects were administered placebo, 12.5, 25, 37.5, and 50 mg doses of atenolol in a randomized single blind design. Each dose was separated by a 1 week washout period. Blood samples were collected at regular intervals from 19.00 hr to 06.00 hr. Repeated measures analysis of variance showed a dose-dependent decrease in plasma melatonin concentrations (P < 0.01). A Student Newman-Keuls post hoc test indicated significant differences between placebo and all doses of atenolol (P < 0.05). The results demonstrate a dose-dependent relationship between β1-receptor blockade and suppression of nocturnal plasma melatonin in humans.

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