Endocrine Abstracts

Sleep and wakefulness are behavioral and physiological activities. It is a modified form of the basic rest activity cycle. Humans usually fall asleep by entering in non Rapid Eye movement sleep, a phase accompanied by characteristic changes in the encephalogram (EEG). The person next moves to REM sleep, which is characterized not only by rapid eye movements but also by inhibition of skeletal muscle tone. These two states alternate with each other during sleep cycle. It has been found that REM sleep is generated as a result of excitation of Cholinergic PS on neurons and inhibition of monaminergic PS off neurons. Moreover the REM sleep deprivation induced increase in Na⁺/ K⁺-ATPase activity which is partially mediated by NE. Serotonin has been found to increase during REM sleep. These facts implicate that both serotonin and norepinepherine are involved during REM sleep. This study has been initiated to find out the effect of norepinepherine and serotonin and the blockers prazosin and propranolol in different permutations and combinations on Na⁺ /K⁺-ATPase activity. Brain from the male wistar rats weighing 250–280 g was extracted and subjected to homogenization, synaptosome was prepared and Na–K-ATPase activity was estimated under the influence of NE (100 μM), 5HT (μM), prazosin (5 mM) and propranolol(5 mM) in different combinations. Both NE and 5HT increase the Na⁺/K⁺-ATPase activity individually and also synergistically when used in combination but in presence of receptor antagonists a decrease is observed. Moreover prazosin and propranolol also decrease the basal values of Na⁺ /K⁺-ATPase activity. We conclude that results will help in exploring the therapeutic possibilities for neurological and other movement disorders associated with norepinepherine and serotonin.