The Effect of Mainstream and Sidestream Smoking on Locomotor Activity in the Adult Male Guinea Pig: Role of Retinoic Acid

Cigarette smoking causes oxidative stress. Oxidative stress has been implicated in neurodegenerative disease, and thereby it may affect the locomotor activity. We have reported earlier that guinea pigs exposed to both mainstream (MS) and sidestream (SS) cigarette smoke have a disturbance in retinoid metabolism in the lung via accumulation of high levels of retinol. Vitamin A deficiency can lead to neurodegenerative disease in adult rats. Here we want to test whether cigarette smoking causes any change in the brain retinoid levels as well as locomotor activity in a guinea pig model. 3‐week‐old male guinea pigs were subjected to MS, SS, or sham smoke exposure, twice daily from 3 cigarettes for 6 weeks. Each day following the cigarette smoke exposure, the locomotor activity of the animals was monitored for 1 hour by Digiscan Animal Activity System. HPLC analysis was used to determine the levels of several retinoids. After 6 weeks of smoking, the brain retinoic acid levels were significantly increased in the MS exposed group compared to the values in the sham group. Hence, cigarette smoking may modify the retinoid metabolism in the brain. The smoke exposed groups exhibited a decrease in locomotor activity over time. This suggests that there may be a correlation between brain retinoid metabolism and locomotor activity. (Supported by Army Grant DAMD17‐03‐2‐0054 and RISE Grant # R25 GM59994)