Effect of Rapid Changes of Light/Dark Cycle on Cholinesterase Activity in the Cerebellum and Prefrontal Cortex of Rats

Background: Spaceflight poses unique physiological stressors, including circadian rhythm disruption, which can impact astronaut health and brain function.Objectives: This study investigated the effects of rapid day/night changes on cholinesterase activity in the rats cerebellum and prefrontal cortex. Methods: Rats were divided into 2 groups (n = 8 per group): Control and circadian disruption with a 45-minute light/45-minute dark cycle. After 14 days of intervention, the cerebellum and prefrontal cortex were harvested from each rat. The samples were washed in ice-cold normal saline solution, weighed, homogenized in phosphate buffer using 1 ml of buffer per 100 mg of tissue, and centrifuged. Moreover, the supernatants were used for the measurement of cholinesterase activity by the photometric method. Results: Mean cholinesterase activity was significantly lower in rats exposed to circadian disruption than in the control group (P 0.05). Conclusions: It seems that cholinesterase activity in rats cerebellum and prefrontal cortex reduces following exposure to rapid light/dark rhythm.