Immunohistochemistric study of the intra-cardiac ganglia of the pig heart

Heart contains a variety of neurons known to influence cardiac functions. Little is known about the neurochemistry of these neurons. In this study, neurochemistry of intra cardiac neurons of the intrinsic cardiac ganglia was investigated. The technique used allows studying the morphology of the ganglionated nerve plexus found within the atria and great cardiac vessels as well as of individual neurons. The epicardial surface of pig hearts obtained postmortem using immunohistochemically staining in conjunction with confocal microscopy neurons in the cardiac intrinsic ganglia immunoreactive for PGP 9.5 identified in the epicardial fat pad around the aortic artery and pulmonary vein. Immunocytochemistry with the marker Protein gene product PGP9.5 was used to study the presence of neurons within clusters of intrinsic cardiac ganglia. Briefly, Tissues were fixed with neutral buffered formalin. Then, they were dissected, dehydrated, cleared, washed and incubated overnight at room temperature with PGP 9.5 (1/1000 in phosphate buffered saline with 0.2 Triton X-100). The slides were washed in PBS and incubated with a mixture of Cy3 labeled Donkey anti-rabbit antibody IgG for 2 hour at room temperature. The slides were evaluated and photographed with a confocal microscope. The results of this study indicate a moderate level of chemical diversity within the intra cardiac neurons of the pig such chemical diversity may reflect functional specialization of neurons in the intra cardiac ganglia. A distinct population of ganglia was seem to arise from in the endocardial plexus of the atria and was predominantly protein gene product 9.5 positive. The small black depressions on the neurons represented satellite cells. Neurons of the intrinsic cardiac ganglia are distributed more widely than has been described in experimented animals. Intra cardiac ganglia formed a complex plexus around the origin of pulmonary veins and were connected by nerve fibers. All neurons included in intrinsic cardiac ganglia contained immunoreactivity to PGP 9.5. Neurons express PGP 9.5 immunoreactivity, suggesting that catecolamine may be present in autonomic nerves in the heart.