THE SLEEP-WAKE CYCLE IN MELATONIN IS PRES ERVED IN HUMAN AFRICAN TRYPANOSOMIASIS

We studied plasma melatonin profiles by radioimmunoassay in nine patie nts suffering from human african trypanosomiasis and six healthy contr ols matched according to the age and the photoperiodic conditions. The circadian periodicity of the sleep-wake cycle was disturbed proportio nally to the degree of severity of the disease. On the contrary, the p atients' plasma melatonin profile was similar to the controls' one. Th ese results suggest that, beside the master clock generating the main circadian rhythms (sleep-wake, melatonin and core temperature rhythms) , an additional regulating system of the melatonin rhythm could be inv olved.