Possible mechanism involved in sleep deprivation-induced memory dysfunction.

Sleep deprivation disrupts various vital biological and metabolic processes that are necessary for health. The present study was designed to investigate the possible mechanisms of sleep deprivation-induced memory dysfunction by using different behavioral, biochemical and neurochemical parameters. Male Wistar rats were sleep deprived for 72 h using a grid suspended over water. Elevated plus maze, passive avoidance and Morris water maze tests were used to assess memory retention in 72-h sleep-deprived animals. Various electrophysiological (sleep-wake cycle), biochemical (lipid peroxidation, reduced glutathione, nitrite, catalase, acetylcholinesterase) and neurochemical parameters (norepinephrine, dopamine and serotonin) were also assessed. Sleep deprivation resulted in memory dysfunction in all the behavioral paradigms, alteration in the sleep-wake cycle (delayed sleep latency, shortening of rapid eye movement [REM] and non-REM [NREM] sleep and increased waking period) and oxidative stress (increased lipid peroxidation and nitrite levels, depletion of reduced glutathione and catalase activity). In addition, increased levels of acetylcholinesterase (AChE; the enzyme responsible for the degradation of acetylcholine) and reduction in norepinephrine and dopamine levels were seen in 72-h sleep-deprived animals. In conclusion, sleep deprivation-induced memory deficits may possibly be due to the combined effect of oxidative damage and alterations in neurotransmitter levels.