[Pressor response to glutamate-injection into hypothalamic paraventricular nucleus and its relation to pressor response of locus coeruleus and depressor response of A1]

Abstract

In urethane-anesthetized, tubocurarine-immobilized and artificially ventilated rats, microinjection of L-glutamate (Glu) into hypothalamic paraventricular nucleus (NPV) or locus coeruleus (LC) induced a pressor response. The LC-pressor response could be attenuated by preinjection of phentolamine or propranolol into bilateral NPV; Preinjection of phentolamine or bicuculline into bilateral NPV could also attenuate the depressor effect of A1-excitation by Glu, but preinjection of propranolol had no such effect; suggesting that the LC-pressor or A1-depressor effect is mediated partly by NPV, and GABAergic inhibitory interneurons in NPV may be involved in A1-depressor response.