Effects of pilocarpine on the cortical and hippocampal theta rhythm in different vigilance states in rats

Effects of acute physical exercise in the light phase of sleep in rats with temporal lobe epilepsy

OBJECTIVE

Our aim was to investigate the influence of an acute exercise session on sleep pattern in rats with temporal lobe epilepsy (TLE).

METHODS

Twenty male Wistar rats were randomly assigned to 4 groups: control (C); acute exercise (EX); epilepsy (E) and epilepsy acute exercise (EEX). Two sleep electrocorticography recordings were performed during the light phase [baseline and day 2 (after the acute physical exercise session)]. After baseline recording, the exercise groups (EX and EEX) were submitted to an exercise session on a motor-driven treadmill at 12m/min for 30min. Twelve hours later, the rats were submitted to the second sleep recording.

RESULTS

At baseline, the E group showed a higher wakefulness and a lower Total sleep time, Slow Wave Sleep and REM sleep compared with the C group. After acute exercise, there was an increase in Total sleep time and Slow Wave Sleep and a decrease of wakefulness in EEX (+11.10%, +20.29% and -11.25%, respectively) and EX (+5.20%, +11.60% and -8.12%, respectively) groups.

CONCLUSION

These findings suggest that acute physical exercise positively impacts the sleep pattern of rats with TLE, inducing a more consolidated sleep.

Effects of the muscarinic agonist pilocarpine on vigilance states and locomotor activity in ring doves

Cholinergic systems play a significant role in regulating a variety of behavioral functions in mammals and birds. The aim of this work is to study the effects of the muscarinic agonist pilocarpine on behavioral states by visual inspection and electroencephalographic recording; also, locomotor activity was continuously recorded by infrared interruption system in ring doves. The current results in birds demonstrated that the muscarinic agonist pilocarpine (1 and 3mg/kg, i.p.) primarily induced theta activity in addition to promote passive waking, while diminished active waking, the EEG slow wave rhythm and REM sleep in ring doves. The locomotor activity recorded continuously in ring doves diminished after pilocarpine treatment, which was in good agreement with the observed reduction of active waking derived of the EEG study. Altogether, the current results are similar to the effects of pilocarpine previously reported in mammals. In conclusion, hippocampal theta rhythm in birds suggests that this rhythm is an ancestral property of hippocampal function and similar cholinergic mechanisms regulate vigilance states and theta generation in mammals and birds.

Effect of oxidative stress induced by paradoxical sleep deprivation on the activities of Na+, K+-ATPase and acetylcholinesterase in the cortex and hippocampus of rat

Several studies revealed the importance of paradoxical sleep as a homeostatic mechanism by which the brain can control oxidative stress. The aim of the present study is to investigate the effect of 72 h of paradoxical sleep deprivation on the oxidative stress markers and its insults on the activities of Na(+), K(+)-ATPase and acetylcholinesterase in the cortex and hippocampus of albino rat. Animals were subjected to paradoxical sleep deprivation for 72 h. At the end of the experiment, the rats were sacrificed, and catalase activity, levels of reduced glutathione, lipid peroxidation, and nitric oxide were assayed together with the activities of Na(+), K(+)-ATPase and acetylcholinesterase in the cortex and hippocampus. The present study revealed a significant increase in lipid peroxidation accompanied by a significant decrease in reduced glutathione in the cortex and hippocampus. Na(+), K(+)-ATPase decreased significantly in both areas. However, acetylcholinesterase showed a significant increase in the investigated brain regions. The present data showed that 72 h of paradoxical sleep deprivation induced oxidative stress in the cortex and hippocampus. It could be suggested that the inhibition of Na(+), K(+)-ATPase and the increased acetylcholinesterase activity may underlie memory impairment, increased brain excitability, and anxiety induced by paradoxical sleep deprivation.