Innervation of cardiac ventricles: an immunohistochemical study in bats (LB46)

Abstract

Neuroanatomy of cardiac ventricles in bats that are adapted for 5‐7 month long hibernation was not identified so far. We used fluorescent immunolabeling for PGP9.5, TH, ChAT, nNOS, SP, and CGRP in order to detect general, sympathetic, vagal and sensory neural structures on ventricles of three species of hibernating bats. We found ventricles in bats to be highly innervated by a dense ganglionated nerve plexus scattered up to heart apex. Ventricular neurons were mostly positive (+) for ChAT, fewer – for TH or nNOS. Small intensely fluorescent cells, strongly TH(+), were identified as well. Epicardial nerves possessed the CGRP(+) and SP(+) nerve fibers. Employing immunohistochemistry for PGP9.5, we revealed numerous sensory nerve endings distributed widely beneath the mesothelium. These nerve endings were solely positive for PGP 9.5 and possessed a complex morphology that was not demonstrated previously. The present findings offer insights into further studies of the hibernating myocardial cells that are fully resistant to long term hypoxia and apparently controlled by autonomic nervous system in perfection.Grant Funding Source: Supported by the Research Council of Lithuania (MIP‐031/2013)