PMID: 2501654Jul 1, 1989Paper

Selective parasympathectomy increases the quantity of inhibitory guanine nucleotide-binding proteins in canine cardiac ventricle

Molecular Pharmacology
T D HodgesR J Kovacs

Abstract

In mammalian heart, vagal stimulation or the direct application of acetylcholine produces profound direct effects on the electro-physiologic characteristics of atrial myocytes. At the tissue level, these effects are observed as shortening of atrial action potential duration. Despite anatomic, biochemical, and physiologic evidence for significant vagal input to the mammalian ventricle, similar direct effects of acetylcholine on the ventricular action potential have been difficult to demonstrate. Chronic denervation via cervical vagotomy is one method that has been shown to render previously unresponsive ventricular myocytes sensitive to acetylcholine, but the molecular mechanism has not been defined. In the experiments described, selective cardiac para-sympathectomy was performed on mongrel dogs. Five to seven days after parasympathectomy, the dogs were sacrificed, electrophysiologic responses to acetylcholine were measured, and sarcolemmal vesicles were prepared. After parasympathectomy, ventricular myocytes were responsive to the effects of acetylcholine, manifested as shortening of the action potential duration. A quantitative and functional assessment of the transmembrane signalling mechanisms of the muscarinic receptor was ...Continue Reading

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