The effects of ozone exposure on the sleep-wake cycle and serotonin contents in the pons of the rat.

Polysomnographic studies were done at hourly intervals during 0.00, 0.35, 0.75 and 1.50 ppm of ozone (O3) exposure. We found a significant decrease in paradoxical sleep after 2 h and an increase in slow wave sleep after 12 h at all concentrations of O3. High resolution liquid chromatography demonstrated an increase in 5-HT concentration in the rat pons, in a roughly stepwise fashion as the O3 concentration increased. We propose that reaction products derived from O3 exposure, such as prostaglandins, could be affecting those physiological and biochemical mechanisms critical for the generation and maintenance of the sleep-wake cycle.