Why Antihistamines Put You to Sleep

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Why Antihistamines Put You to Sleep

Thu May 27,11:47 PM ET

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THURSDAY, May 27 (HealthDayNews) -- Brain cells that contain the chemical

histamine are critical for waking, says a study by scientists at the

Veterans Affairs' Neurobiology Research Laboratory and University of

California, Los Angeles (UCLA) Neuropsychiatric Institute.

The study, which utilized dogs with the sleep disorder narcolepsy, found

that cessation of activity in brain cells with histamine causes loss of

consciousness during sleep. The findings may explain why antihistamine drugs

cause drowsiness.

The researchers also found that cessation of activity in brain cells that

contain the chemicals norepinephrine or serotonin causes loss of muscle tone

during sleep.

The study appears in the May 27 issue of Neuron.

" Our findings greatly improve our understanding of the brain activity

responsible for maintaining consciousness and muscle tone while awake, "

senior author Dr. Jerome Siegel, chief of neurobiology research at the VA

Greater Los Angeles Health Care System in Sepulveda, said in a prepared

statement.

" The findings should aid in the development of drugs to induce sleep and to

increase alertness, " Siegel said.

The U.S. National Institute of Neurological Disorders and Stroke has more

about sleep.