Possible origins of cerebrovascular nerve fibers showing vasoactive intestinal polypeptide-like immunoreactivity: an immunohistochemical study in the dog

Abstract

Changes of vasoactive intestinal polypeptide-like immunoreactivity (VIP-LI) in perivascular nerve fibers of the major cerebral arteries were examined immunohistochemically in the dog. The density of cerebrovascular nerve fibers showing VIP-LI (the averaged number of nerve fibers with VIP-LI in a unit area of the major cerebral arteries) was estimated, by using whole-mount preparations, after extirpation of the pterygopalatine, otic or superior cervical ganglion. After pterygopalatine ganglionectomy, the density was markedly decreased in major cerebral arteries of both anterior circulation (the anterior cerebral and middle cerebral arteries) and posterior circulation (the basilar, superior cerebellar, posterior cerebral and posterior communicating arteries). After otic ganglionectomy, the density was moderately reduced in the major arteries of the posterior circulation, but was not decreased in those of the anterior circulation. After superior cervical ganglionectomy, the density was decreased markedly in the major cerebral arteries of the posterior circulation, and moderately in those of the anterior circulation. The results also indicate that the pterygopalatine, otic and superior cervical ganglia supply perivascular nerve fibers showing VIP-LI to the major cerebral arteries bilaterally with an ipsilateral dominance.