Morpho-Functional Study of Cardioactive Neurohormones and Some Other Neuropeptides in the Nervous and Cardiac Systems of Rats in Normal and Pathological Conditions

This review presents data from multilateral studies, aimed at determining the localization, release and the function of the cardioactive hormones found by acad. A. Galoyan and colleagues in the hypothalamic-pituitary system of the bovine brain. The isolated protein-carriers of the neurohormones K, C and G (PCK, PCC, PCG) have been found to differ from the protein-carrier of the vasopressin and oxytocin neurophysin. The coronary-dilating factors were also isolated from the bovine heart and medulla of the adrenal gland. Later, in various regions of the intact rat brain, PCG was immunohistochemically detected in the glial and nerve cells, as well as in the varicose nerve fibers and synaptosomes. In the intact rat heart, PCG was localized in the nerve fibers, as well as in the small catecholamine-containing SIF cells. Fourteen days after the unilateral vagotomy, aimed at clarifying the origin of PCG-IR in the heart, some PCG-Ir nerve fibers around the cardiomyocytes and the ganglion cells were detected mainly due to the preserved SIF cells and SCG sympathetic neurons containing PCG. PCG-immunonegative cardiac ganglion cells in both intact and colchicine-treated rats were excluded as a possible source of the external PCG-IR. Thus, PCG, together with the other neuropeptides studied by us (NPY, CGRP and VIP, SP, LENK) present in SIF cells, can be involved in the local regulatory mechanisms of the heart, thereby confirming the idea proposed by A. Galoyan regarding the “neurosecretion of the heart” and the literature data on the existence of the peptidergic system of the heart.