Electrical stimulation in the rat of the supraoptic nucleus: failure to alter plasma corticosterone after surgical lesioning of the paraventricular nucleus.

Electrical stimulation of the supraoptic nucleus (SON) for 3 min in dexamethasone-morphine-pentobarbital-pretreated rats raised the plasma level of corticosterone; 4 days after placing a surgical lesion in the hypothalamic paraventricular nuclei (PVN) electrical stimulation of the SON failed to change the plasma level of corticosterone. We suggest that nerve fibres originating in or near the PVN that pass near the SON are likely to contain corticotropin releasing factor and elicit and release of ACTH following electrical stimulation.