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Influence of beta-blockers on melatonin release
K Stoschitzky1, A Sakotnik, P Lercher
1Department of Medicine, Karl Franzens University, Graz, Austria.
European Journal of Clinical Pharmacology
|May 21, 1999
Summary
Beta-blockers, specifically their S-enantiomers, significantly reduce nocturnal melatonin production by inhibiting beta1-receptors. This finding may explain sleep disturbances and suggests melatonin supplementation as a potential countermeasure.
Area of Science:
- Pharmacology
- Endocrinology
- Circadian Biology
Background:
- Melatonin, produced by the pineal gland, regulates circadian rhythms.
- Adrenergic receptors (beta1 and alpha1) stimulate melatonin production.
- Beta-blockers are known to cause sleep disturbances, but their effect on melatonin is unclear.
Purpose of the Study:
- To investigate the influence of specific beta-blockade and combined alpha- and beta-blockade on human melatonin production.
- To determine the enantiomer-specific effects of beta-blockers on melatonin synthesis.
Main Methods:
- A randomized, double-blind, placebo-controlled, cross-over study was conducted in 15 healthy volunteers.
- Subjects received single oral doses of various beta-blocker enantiomers (propranolol, atenolol), carvedilol, verapamil, or placebo.
- Urinary 6-sulfatoxy-melatonin (aMT6s) was measured via radioimmunoassay.
Main Results:
- The S-enantiomers of propranolol and atenolol significantly reduced nocturnal aMT6s excretion by 80% and 86%, respectively (P < 0.001 and P < 0.01).
- The R-enantiomers of propranolol and atenolol, which lack beta-blocking activity, showed no significant effect on aMT6s levels.
- (R,S)-carvedilol, a combined alpha- and beta-blocker, did not significantly alter melatonin metabolite excretion.
Conclusions:
- Beta-blockers decrease melatonin release through specific inhibition of beta1-adrenergic receptors.
- Reduced nocturnal melatonin may contribute to beta-blocker-induced sleep disturbances.
- Further research should explore melatonin supplementation to mitigate this side effect; the lack of effect of carvedilol warrants further investigation.