Cerebral Arteries Of Calcitonin Gene-related Peptide Containing Nerve Fibers In The Morphological Observation

Objective:To study the innervation oCCalcitonin gene-related peptidergic (CGRP-ergic) nerve on cerebral arteries in rats, and to probe into the flR)rpllological bases of the neurogenic regulation about pepetidergic nerves on cerebral vessels in rats. Methods: 14 adult Sorague-Dwaely (SD) rats and 14 agcd Sprngue-Dwaely rats, used as control group, were studied with immunohistochemical ABC technique, counting number of nerve intersections and with the technique of sheeting. Results: (1) The immunopositive fibers with the black linear structure were observed on the anterior cerebral artery(ACA), middle cerebral artery(MCA), posterior cerebral artery(PCA), basilar artery(BA), the intracranial part of the vertebral artery(l VA) in adult and aged rats, the density of immunoreactive fibers comes in the following order: ACA>MCA>PCA>BA>IVA. Statistical analysis indicates that there is significant difference in density between each two arteries; (2) The characteristic running patterns of the immunopositive fibers included circular, meshwork and longitudinal, i.e. mainly in circular fashion (64.29%) in adult rats, in meshwork (67.46%) in aged rats; (3) The type of distribution of CGRP-ergic nerve in the proximal of MCA was mainly circular (5 7.14%), next meshwork and longitudinal, of the middle mostly meshwork (85.71%), partly circular and longitudinal, and of the end mostly longitudinal (85.71%), partly meshwork and circular. The density of fibers of the proximal of MCA was higher, of the end lower, and of the middle in between; (4) Compared with the namesake artery of the adult rats, CGRP-ergic positive nerve fibers in ACA, MCA, PCA of aged rats decreased obviously, in BA, IVA remained unchanged. Student's t-test was used and P<0.01. Conclusion: There were different distribtttion characteristics on the different cerebral artery and on the different portions of the same cerebral artery. It suggests that the regulation of CGRP-ergic nerve differs in different cerebral artery. The density of CGRP-ergie nerve fibers in aged rats is lower than in adult rats. It is related to decreased vasodilator mechanism and changes of autoregulation of cerebral artery in aged. It also suggests that CGRP-ergic nerve played an important role in origination and development of aged cerebral vessel diseases...