Donald B. Hoover*, Yingzi Chang, John C. Hancock and Lili Zhang
Department of Pharmacology, James H. Quillen College of Medicine, East
Tennessee State University, P.O. Box 70577, Johnson City, TN 37614, USA
*Corresponding author: FAX:+1-423-439-8773
E-mail: hoover@etsu.edu
Abstract: SubstanceﾊP and neurokininﾊA are tachykinins that are co-localized
with calcitonin gene-related peptide (CGRP) in a unique subpopulation of
cardiac afferent nerve fibers. These neurons are activated by nociceptive
stimuli and exhibit both sensory and motor functions that are mediated by
the tachykinins and/or CGRP. Sensory signals (e.g., cardiac pain) are transmitted
by peptides released at central processes of these neurons, whereas motor
functions are produced by the same peptides released from peripheral nerve
processes. This review summarizes our current understanding of intracardiac
actions of the tachykinins. The major targets for the tachykinins within
the heart are the intrinsic cardiac ganglia and coronary arteries. Intrinsic
cardiac ganglia contain cholinergic neurons that innervate the heart and
coronary vasculature. Tachykinins can stimulate NK3 receptors
on these neurons to increase their excitability and evoke spontaneous firing
of action potentials. This action provides a mechanism whereby tachykinins
can indirectly influence cardiac function and coronary tone. Tachykinins
also have direct effects on coronary arteries to decrease or increase tone.
Stimulation of NK1 receptors on the endothelium causes vasodilation
mediated by
Keywords: Tachykinin, Cholinergic neuron, Coronary artery, Cardiac afferent,
Myocardial ischemia
Copyrightｩ The Japanese Pharmacological Society 2000
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