INFLUENCE OF CHRONIC BETA-ADRENOCEPTOR BLOCKER TREATMENT ON MELATONINSECRETION AND SLEEP QUALITY IN PATIENTS WITH ESSENTIAL-HYPERTENSION

The nocturnal production of melatonin synthesis has been associated wi th circadian mechanisms of the organization of sleep. It is well known that the synthesis of melatonin is under the control of pineal beta(1 )-adrenoreceptors. In this study the effect of ten weeks treatment wit h the beta-adrenoreceptor (beta-AR) blockers propranolol and ridazolol on melatonin synthesis and on sleep quality was examined in 42 patien ts suffering from essential hypertension. Before and after 6 and 10 we eks of beta-AR-blocker administration urinary sulfatoxymelatonin excre tion rates were measured and sleep factors were evaluated by using a s tandardized sleep inventory consisting of self-rating sleepiness scale s. After 6 and 10 weeks of treatment, a significant about 50 percent r eduction of sulfatoxymelatonin was measured. No relationship between t hese reductions and changes in sleep factors was found. The results in dicate that a reduced nightly amplitude of melatonin has minor signifi cance for the organization of physiological sleep. Furthermore, it is suggested that pineal mechanisms beside the beta(1)-adrenergic recepto r transduction system serve to maintain the melatonin signal to a cons iderable extent during a chronic beta 1-AR blockade.