Reflexly evoked coactivation of cardiac vagal and sympathetic motor outflows: observations and functional implications

JFR Paton, E Nalivaiko, P Boscan, AE Pickering

Research output: Contribution to journalArticle (Academic Journal)peer-review

48 Citations (Scopus)

Abstract

1. The purpose of the present review is to highlight the pattern of activity in the parasympathetic and sympathetic nerves innervating the heart during their reflex activation. 2. We describe the well-known reciprocal control of cardiac vagal and sympathetic activity during the baroreceptor reflex, but point out that this appears to be the exception rather than the rule and that many other reflexes reviewed herein (e.g. peripheral chemoreceptor, nociceptor, diving response and oculocardiac) involve simultaneous coactivation of both autonomic limbs. 3. The heart rate response during simultaneous activation of cardiac autonomic outflows is unpredictable because it does not simply reflect the summation of opposing influences. Indeed, it can result in bradycardia (peripheral chemoreceptor, diving and corneal), tachycardia (nociceptor) and, in some circumstances, can predispose to malignant arrhythmias. 4. We propose that this cardiac autonomic coactivation may allow greater cardiac output during bradycardia (increased ventricular filling time and stronger contraction) than activation of the sympathetic limb alone. This may be important when pumping blood into a constricted vascular tree, such as is the case during the peripheral chemoreceptor reflex and the diving response.
Translated title of the contributionReflexly evoked coactivation of cardiac vagal and sympathetic motor outflows: observations and functional implications
Original languageEnglish
Pages (from-to)1245 - 1250
Number of pages6
JournalClinical and Experimental Pharmacology and Physiology
Volume33(12)
Publication statusPublished - Dec 2006

Bibliographical note

Publisher: Wiley

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