An autoradiographic analysis of [3H]alpha-bungarotoxin distribution in the rat brain after intraventricular injection

Purified alpha-bungarotoxin was isolated by chromatography and made radioactive with tritium ([3H]acetamidino-alpha-bungarotoxin). Infusions of [3H]alpha-bungarotoxin alone or preceded by tubocurarine or atropine were given into the third ventricle. 2. 12, or 24 h after injection the brains were prepared for autoradiography. Injections of alpha-bungarotoxin (radioinert) in buffer, or of [3H]parathyroid hormone in buffer, served as controls. The various patterns of labeling suggest the presence of nicotinic-cholinergic neurons within the arcuate and basolateral regions of the hypothalamus including the supraoptic and suprachiasmatic nuclei and, in addition, the central nucleus of the amygdala.