Distribution of Muscarinic Receptors and Acetylcholinesterase in the Rat Heart
Document Type
Article
Publication Date
1-1-1987
Description
Experiments were performed to determine the degree of overlap in the distribution of muscarinic receptors and cholinergic innervation of the rat heart. Localization of muscarinic receptors was determined by autoradiography with [3H]quinuclidinyl benzilate. Adjacent sections were stained for acetylcholinesterase to determine innervation. The distribution of muscarinic receptors and cholinergic innervation overlapped in cardiac parasympathetic ganglia, nodal tissue, His bundle-Purkinje system, vena cava and pulmonary veins. Cholinergic innervation to the right atrium was greater than to the left atrium while muscarinic receptor density was equal in the two atria. Innervation of the ventricles was confined primarily to the base of the right ventricle. A low density of muscarinic receptors was observed throughout the ventricles. Neither cholinergic innervation nor muscarinic receptors were detected in the pulmonary trunk, ascending aorta or cardiac valves. Muscarinic receptors and cholinergic innervation in the nodal regions, ventricular conduction system and myocardium probably mediate negative chronotropic, dromotropic and inotropic effects of vagal nerve stimulation. Muscarinic receptors at sites not containing cholinergic innervation may be associated with noradrenergic nerves of the myocardium.
Citation Information
Hancock, John C.; Hoover, Donald B.; and Hougland, Margaret W.. 1987. Distribution of Muscarinic Receptors and Acetylcholinesterase in the Rat Heart. Journal of the Autonomic Nervous System. Vol.19(1). 59-66. https://doi.org/10.1016/0165-1838(87)90145-7 PMID: 3598049 ISSN: 0165-1838