MATCHING LOCALIZATION OF VASOACTIVE INTESTINAL POLYPEPTIDE (VIP) AND VIP-RECEPTOR AT PRESYNAPTIC AND POSTSYNAPTIC SITES IN THE MOUSE VISUAL-CORTEX

Vibratome sections of the mouse occipital cortex were processed by dou ble label immunohistochemistry to demonstrate the localization of the receptor for vasoactive intestinal polypeptide and the peptide itself. The receptor was found to be distributed in the cytoplasm and major d endrites of numerous cortical cells, mainly pyramidal neurons. Vasoact ive intestinal polypeptide, on the other hand, occurred in a populatio n of non-pyramidal neurons and axonal boutons. Image analysis revealed a close spatial association of peptide-containing presynaptic termina ls with receptor-containing cells. Ultrastructurally, these connection s represented symmetrical axo-somatic and axo-dendritic synapses. Our findings demonstrate a matching histological localization of vasoactiv e intestinal polypeptide and its receptor in the brain.