Sleep alterations and brain regional changes of serotonin and its metabolite in rats exposed to ozone.

Sleep alterations and brain regional changes of serotonin were studied in rats exposed to 1.5 ppm of ozone (O3). Results showed a significant decrease in the time spent in wakefulness (W) and paradoxical sleep (PS) and a significant increase in the time spent in slow wave sleep (SWS). Neurochemical analysis showed a significant increase in the metabolism of serotonin in medulla oblongata, pons and midbrain, while both serotonin and its metabolite were reduced in hypothalamus. Although other neurotransmitters could be affected by O3 exposure, the sleep disorders observed in the present work may be related to alterations in the metabolism of serotonin produced by the exposure to O3.