THE DORSAL VAGAL COMPLEX OF THE FERRET - ANATOMICAL AND IMMUNOHISTOCHEMICAL STUDIES

To further the understanding of gastrointestinal function in this spec ies, and in particular to advance our own work concerning central emet ic pathways, the cytoarchitecture and the distribution of eight neuroc hemicals were studied in the ferret dorsal vagal complex (DVC; area po strema, nucleus of the solitary tract [nTS] and dorsal motor nucleus o f the vagus). The cytoarchitectural features of this region in the fer ret were similar to those seen in other species; however, the ferret p ossesses a particularly large and distinct subnucleus gelatinosus of t he nTS. Dense calcitonin gene-related peptide-immunoreactivity was fou nd in the gelatinous, interstitial and commissural subnuclei of the nT S, with lesser amounts in other regions of the DVC. Enkephalin-immunor eactivity of varying densities was found throughout the DVC. Moderate to dense galanin-immunoreactivity was observed throughout the DVC, wit h the exception of the subnucleus gelatinosus of the nTS, from which i t was virtually absent. Dense neuropeptide Y-immunoreactivity was obse rved in the subnucleus gelatinosus and interstitial subnucleus, with m oderate staining in other regions of the DVC, Neurotensin immunoreacti vity was very sparse or absent. Immunoreactivity for serotonin was spa rsely distributed throughout the DVC. Moderate somatostatin-immunoreac tivity was observed over a large portion of the DVC, bur was virtually absent from the gelatinosus and interstitial subnuclei. Substance P i mmunoreactivity was observed throughout the DVC and was particularly d ense in the dorsal/dorsolateral subnucleus and the dorsal aspects of t he medial and commissural subnuclei. In terms of its cytoarchitecture the DVC of the ferret is more similar to the cat than the mt, especial ly with regard to the area postrema and the subnucleus gelatinosus of the nTS. The distribution of neuroactive substances was largely simila r to other species; however, differences were present particularly in patterns of immunoreactivity for enkephalin, serotonin, neuropeptide Y and somatostatin.