VIP-LIKE IMMUNOREACTIVITY WITHIN NEURONS AND PERIVASCULAR NEURONAL PROCESSES OF THE HUMAN CEREBRAL-CORTEX

Using indirect immunocytochemical techniques, neurons with VIP (Vasoac tive Intestinal Polypeptide)-like immunoreactivity (ir) have been demo nstrated in the human cerebral cortex of the parietal lobe. In all the cortical layers containing positive neurons, perivascular immunoreact ive neuronal processes have been detected: in arterioles, they are loc ated in the adventitial and smooth muscle layers; in capillaries, they establish tight anatomical relations with the endothelium-pericyte la yer and the perivascular glial sheath. Bodies of positive neurons have also been seen adhering to capillary walls. The detection of perivasc ular VIP-like ir provides morphological evidence of the role played by this polypeptide in the regulation of the cerebral blood flow. Moreov er, the relationships between immunoreactive neuronal processes and pe rivascular glia might corroborate the suggestion that VIP is involved in the functioning of the blood-brain barrier.