engleski

Sleep disturbances and platelet serotonin in alcoholism

Introduction: Chronic alcoholism is frequently associated with sleep disorders, disrupted sleep, insomnia, mood instability and craving. Namely, alcohol affects sleep latency, disrupts the sleep periods during night, affects rapid eye movement sleep and elicits frequent episodes of wakefulness, and frequent shifts between sleep stages. Alcoholics often experience insomnia, especially during the withdrawal syndrome. In addition, insomnia is a risk factor for relapse into addiction of alcohol. Although the consumption of alcohol may improve sleep latency at the beginning of alcohol abuse, at later stages chronic alcoholism is associated with poor sleep quality, early wakening, and insomnia. Numerous neurotransmitters have been implicated in regulation of normal and irregular sleep behavior, and in the etiology of alcoholism. Serotonin (5-hydroxytryptamine, 5-HT) has a major role in the control of many physiological and pathological functions and behaviors, including sleep, wakefulness, arousal states, vigilance behaviors, synchronization of the biological clock and circadian rhythmicity. Serotonergic neurotransmission from the dorsal raphe is associated with arousal and is turned off during sleep. Serotonin has a role in etiology of alcoholism. Central 5-HT synaptosomes and platelets similarly store, release and metabolize 5-HT, and therefore blood platelets might be used as a limited peripheral model for the central 5-HT synaptosomes. Platelet 5-HT concentration has been proposed to represent a biomarker for particular symptoms in psychiatric disorders, to be reduced in chronic alcoholics, and in subjects with disturbed sleep. Materials and Methods: Platelet 5-HT concentration was determined in male and female patients with chronic alcoholism, subdivided into patients with or without insomnia with a spectrofluorimetric method. Clinical diagnosis of alcohol dependence made according to the DSM-IV criteria, using Structured Clinical Interview. Insomnia was evaluated using the items 4, 5 and 6 from the Hamilton Rating Scale for Depression, and alcoholics were subdivided into those with early, middle and late insomnia. Results: Male alcoholic patients with middle insomnia had significantly lower platelet 5-HT concentration compared to male alcoholics without middle insomnia. Platelet 5-HT concentration did not differ significantly among male alcoholic patients with or without early or late insomnia, or between female alcoholic patients with or without early, middle and late insomnia. Conclusions: Since ethanol improves the onset of sleep, while at the same time the duration of sleep is disturbed, lower platelet 5-HT concentration in middle insomnia suggest that this peripheral marker is altered in alcoholics with middle insomnia.

platelet serotonin; alcoholism; sleep disturbances

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