Norepinephrine depletion in the paraventricular nucleus inhibits the adrenocortical responses to neural stimuli

In view of the importance of the paraventricular nuclei of the hypothalamus (PVN) in the regulation of adrenocortical secretion and the possible role of norepinephrine (NE) in this mechanism, we have studied the effects of injecting the catecholamine neurotoxin 6-hydroxydopamine into the PVN on basal corticosterone (CS) secretion and following ether stress and neural stimuli. PVN NE depletion did not affect the basal and the ether stress-induced rise in CS levels. However, it inhibited significantly the adrenal response to photic, acoustic and sciatic nerve stimulation, suggesting that the PVN NE plays a role in the activation of adrenocortical responses following afferent neural stimuli.