AJP - Regulatory, Integrative and Comparative Physiology, Vol 272, Issue 3 896-R901, Copyright © 1997 by American Physiological Society

ARTICLES

Neurocardiac response to esophageal electric stimulation in humans: effects of varying stimulation frequencies

A. Bajwa, S. Hollerbach, M. V. Kamath, A. R. Upton, D. Fitzpatrick, E. L. Fallen and G. Tougas
Division of Gastroenterology, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada.

The purpose of this study was to determine if the cardioautonomic responses to esophageal electric stimulation were mediated entirely through modulation of respiratory frequency or a direct vagal effect. We performed electric stimulation of the esophagus in 13 healthy male controls (24 +/- 6 yr) using a manometric catheter to which a stainless steel electrode was attached. Stimulation frequencies ranged from 0.1 to 1 Hz and were applied in random fashion. We computed the power spectra of the heart rate variability and respiratory frequency as measures of autonomic function. Electric stimulation of the esophagus produced significant increases in the high-frequency power of the heart rate autospectrum at all stimulation frequencies (maximal at 0.2 Hz). However, regardless of the frequency of esophageal stimulation, the respiratory rate was not changed from baseline. These studies indicate that enhancement of cardiac vagal modulation observed in response to esophageal electric stimulation is not primarily due to changes in respiratory frequency, but rather occurs through a direct, vagally mediated action through sensory neural pathways involving vagal esophageal afferents.

This article has been cited by other articles:

				G Tougas, R Spaziani, S Hollerbach, V Djuric, C Pang, A R M Upton, E L Fallen, and M V Kamath Cardiac autonomic function and oesophageal acid sensitivity in patients with non-cardiac chest pain Gut, November 1, 2001; 49(5): 706 - 712. [Abstract] [Full Text] [PDF]