ROLE OF MEDIAL PREOPTIC AREA BETA-ADRENOCEPTORS IN THE REGULATION OF SLEEP-WAKEFULNESS

The role of the medial preoptic area (mPOA) beta adrenergic receptors in the regulation of sleep-wakefulness (SW) was investigated in this s tudy. S-W was assessed on the basis of polygraphic recording of EEG, E MG and EOG, in free moving rats. Intracerebral microinjection of beta agonist, isoproterenol, into the mPOA produced arousal. The study was also conducted on another set of rats in which noradrenergic (NE) inne rvation to the mPOA was destroyed by injecting 6-hydroxydopamine into the ventral noradrenergic bundle, in the brain stem. Local application of isoproterenol, into the mPOA, in these animals, did not produce an y significant change in S-W. Thus, the increase in awake period obtain ed on isoproterenol administration was the result of its action on the presynaptic NE terminals. Possible involvement of other responses in the isoproterenol induced increase in wakefulness, is discussed. (C) 1 997 Elsevier Science Inc.