Regional Distribution of Choline Acetyltransferase Activity and Multiple Affinity forms of the Muscarinic Receptor in Heart
- 65 Downloads
The autonomic nervous system plays an important role in the regulation of the heart. The parasympathetic division decreases heart rate and contractility while the sympathetic division mediates the opposite responses. The parasympathetic effect predominates at rest and provides tonic inhibitory influences. The parasympathetic system also predominates when both divisions are maximally stimulated (1). The preganglionic component of the parasympathetic system originates in the dorsal motor nucleus of the brain stem and courses to the heart through the vagus nerves. Postganglionic (intrinsic) neurons originate and terminate within the heart. Acetylcholine is the neurotransmitter of both the preganglionic and postganglionic divisions of the parasympathetic system. The response between the pre- and postganglionic neurons is mediated by the cholinergic nicotinic receptor. The postganglionic neurons interact with the myocardium and its specialized pacemaker tissue by means of the cholinergic muscarinic receptor. Choline acetyltransferase activity in heart is a neurochemical marker of both the pre- and postganglionic neurons of the parasympathetic system in unknown proportion.
KeywordsTyrosine Hydroxylase Muscarinic Receptor Choline Acetyltransferase Cholinergic Muscarinic Receptor Parasympathetic System
Unable to display preview. Download preview PDF.
- 1.M.N. Levy, Parasympathetic control of the heart. In: Neural regulation of the heart. W.C. Randall, ed., pp. 95–129 New York: Oxford University Press (1977).Google Scholar
- 4.Potter, L.T., Acetylcholine in Handbook of Neurochemistry. Vol IV, A. Lajtha ed., New York, Plenum Press, pp 263–284 (1970).Google Scholar
- 8.D.D. Lund, P.G. Schmid, and R. Roskoski, Jr., Choline acetyltransferase activity in rat and guinea pig heart following vagotomy. Am. J. Physiol. H620 (1974).Google Scholar
- 18.D.D. Lund, P.G. Schmid, U.J. Johannsen, and R. Roskoski, Jr., Biochemical indices of cholinergic and adrenergic autonomic innervation in chronic right heart failure. J. Mol. Cell Cardiol. in press.Google Scholar
- 19.P. Toscano, and L.T. Potter, Distribution of muscarinic receptors (MR) in relation to choline acetyltrans-ferase in the human heart. Fed. Proc. 41:1327.Google Scholar
- 20.W.C. Randall, Sympathetic control of the heart. In: Neural regulation of the heart, W.C. Randall, ed., pp. 43–94. New York, Oxford University Press (1977).Google Scholar
- 26.W.H. Enseleit, R.G. Bassett, Jr. and R. Roskoski, Jr., Modification of muscarinic receptor-ligand binding in the rat heart by 5’-guanylylimidodiphosphate, Fed. Proc. 41:1211 (1982).Google Scholar
- 30.R.R. Reinhardt, and R. Roskoski, Jr., Methacholine induced decrease of the cholinergic muscarinic receptor in the perfused working rat heart. Fed. Proc. 41:898 (1982).Google Scholar