Vasoactive intestinal peptide receptor localization in rat forebrain by autoradiography

Vasoactive intestinal peptide (VIP) receptors were localized in rat forebrain by in vitro labeling light microscopic autoradiography with 125I-labeled VIP. Binding sites for VIP were found in discrete areas of rat forebrain including lamina I of the neocortex and pyriform cortex, caudate-putamen, the hippocampus and molecular layer of the dentate gyrus, basolateral nucleus of the amygdala, several thalamic nuclei and the magnocellular paraventricular and supraoptic nuclei of the hypothalamus. These results are consistent with earlier findings on the immunohistochemical distribution and proposed sites of action of VIP, and reinforce the concept that endogenous VIP may function as a neuromodulator in brain.