Morphological innervation pattern of the developing rabbit heart

Abstract

The morphological innervation pattern of developing fetal and neonatal rabbit hearts was delineated histochemically by a cholinesterase/silver procedure and immunohistochemically with the monoclonal antibody HNK1, an antibody which recognizes some cells derived from neuroectoderm. Cholinesterase-containing nerves appeared distally on the outflow tract by gestational day 15 (G15). Isolated cells with cholinesterase-stained fine processes were present near the base of the pulmonary trunk. HNK1 antibody stained the same nerves and ganglia revealed by the cholinesterase reaction and other nerves in the rabbit heart. It was used to confirm that cells with fine neuron-like processes were present before nerve ingrowth. The G14 heart contained many HNK1 staining cells in the right atrium, outflow, and inflow tracts; cells with fine processes were few but increased at G16. By G17, a plexus of interweaving nerves and associated cells began to form at the base of the pulmonary trunk. Fine nerves encircled the base of the aorta, and others crossed the intercaval region dorsally. At G19, nerves 1) extended downward from a rich "bulbar" plexus along the front ventricular surface, 2) grew near the epicardial surface at the base of the heart along the atrial floor and ventricular roof, 3) traversed the vena cavae and intercaval region to enter the atrial roof, and 4) crossed the coronary sinus to reach the back ventricular walls. By G23, cholinesterase-staining nerves and ganglia in the atria and, epicardially, in the ventricles formed the general innervation pattern of the newborn and adult rabbit heart.

Distribution of antigen epitopes shared by nerves and the myocardium of the embryonic chick heart using different neuronal markers

“…Later on, nerve fibers penetrate the free wall of the atrial and ventricular working myocardium. This has not been described before in the chick, although this sequence is also known in the human (Gordon et al, 1993) and the rabbit heart (Roberts, 1991). In agreement with the findings of Higgins and Pappano (1979) we find that the atrial myocardium is populated by adrenergic nerve fibers slightly in advance of the ventricular myocardium.…”

“…Furthermore, the sequential nerve ingrowth into different parts of the ventricular free wall from base to apex and from epicardium toward endocardium is also in agreement with their observations. The sequence of ventricular nerve ingrowth and the advanced innervation of the atria is also reported in mammalian hearts (Papka, 1981;Roberts, 1991;Ursell et al, 1990) including humans (Gordon et al, 1993). However one difference is that in the chick we did not observe a higher density of nerve fibers in the atrial myocardium as compared with the ventricular myocardium shortly before birth at HH44, as has been found in the dog (Ursell, 1990) and human (Gordon et al, 1993;Chow et al, 1995).…”

The autonomic nervous system of the human heart with special reference to its origin, course, and peripheral distribution

“…Thereafter, the sympathetic cardiac nerves secondarily extend to the heart, forming the cardiac plexus when the morphogenesis of the branchial arteries is nearly complete (Sharner 1930;Gomez 1958;Kuratani et al 1991;Roberts 1991). Interestingly, the mixing positions (cardiac plexus) of the sympathetic cardiac nerve and the vagal cardiac branch, as well as the definitive morphology of brachial arteries with the recurrent laryngeal nerves, tended to differ on the two sides.…”

Anatomy of the cardiac nervous system with clinical and comparative morphological implications

“…Mammalian and avian ontogenetic developmental investigations of ACNS have been presented in a number of studies (Sharner 1930;Gomez 1958;Kirby et al 1980;Kuratani and Tanaka 1990;Kuratani et al 1991;Roberts 1991;Verberne et al 1998;Shoba and Tay 2000;Hildreth et al 2009). In mouse, the parasympathetic vagal nerves are first observed in the venous porta at E10.5 (10.5 days after fertilization) and reach the heart by E12.5, whereas the innervation of the outflow (arterial porta) occurs slightly later (Hildreth et al 2009).…”