Different types of norepinephrinergic receptors are involved in preoptic area mediated independent modulation of sleep-wakefulness and body temperature

Abstract

The preoptic area is known to regulate sleep-wakefulness and body temperature. It was suggested earlier that though sleep-wakefulness and body temperature may effect each other, the preoptic area mediated influence on those two physiological phenomena is likely to be independent of alteration in each other. Since intrapreoptic area norepinephrine could modulate both those functions, study of that system was undertaken. It was hypothesized that since the preoptic area has different types of norepinephrinergic receptors (viz. α₁, α₂ and II), independent modulation of those two functions was probably due to activation or inactivation of separate receptors. Hence, the effects of different agonist and antagonist of those receptors individually as well as in combunation into the preoptic area were studied on those two functions is freely moving rats. The results suggest that norepinephrine induced preoptic area mediated influence on the body temperature is primarily regulated by the α₁ receptors while the sleep and wakefulness are regulated by α₂ and β recetors, respectively, The finding should help in explaining several poorly understood observations reported earlier and it suggests that similar phenomena may possibly exist in other system involving other neurotransmitters as well.