IMMUNOHISTOCHEMICAL DEMONSTRATION OF GALANIN, AND GALANIN MESSAGE-ASSOCIATED PEPTIDE-LIKE IMMUNOREACTIVITIES IN SYMPATHETIC-GANGLIA AND ADRENAL-GLAND OF THE GUINEA-PIG

Using the indirect immunofluorescence method, the distribution of gala nin (GAL)- and galanin message-associated peptide (GMAP)-like immunore activities (LI) were studied in sympathetic ganglia and the adrenal gl and of the guinea pig. A rather dense network of GAL-immunoreactive ne rve fibers was found in the inferior mesenteric ganglion (IMG) and in the superior mesenteric pole of the celiac-superior mesenteric ganglio n complex (C-SMG). The celiac pole of the C-SMG, the stellate ganglion , and the superior cervical ganglion contained fewer, mostly scattered fibers. SIF-cells in prevertebral and paravertebral ganglia contained GAL-LI, as did the adrenal medullary cells. The GAL fibers in the IMG surrounded mainly principal ganglion cells containing somatostatin-im munoreactivity (SOM-IR), whereas fewer fibers were seen around neurope ptide Y (NPY) cells and cells in which SOM and NPY coexisted. Applicat ion of colchicine or vinblastine onto the IMG did not result in the ap pearance of GAL-IR in the principal ganglion cells. In denervation exp eriments it was revealed that most of the GAL fibers reach the IMG via the lumbar splanchnic nerves. GAL-IR appears to be colocalized with s ubstance P (SP) in fibers of the IMG, indicating an origin of the GAL- containing fibers in dorsal root ganglia (DRG). This conclusion was su pported by the finding in lumbar DRGs of GAL-positive cell bodies that contained SP. The role of GAL in prevertebral ganglia is unclear. It may be suggested that GAL modulates the slow, long-lasting membrane de polarization of the principal ganglion cells caused by SP in the prima ry afferents related to the IMG. GMAP-LI was detected in SIF cells and adrenal medullary cells in which GMAP-LI parallels the immunoreactivi ty of GAL. GMAP-LI was not observed in neuronal cell bodies or nerve f ibers of the ganglia. (C) 1994 Wiley-Liss, Inc.