HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/1/R215    most recent 00112.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Harris, M. B. Articles by St.-John, W. M. Search for Related Content PubMed PubMed Citation Articles by Harris, M. B. Articles by St.-John, W. M.

CARDIAC, RENAL, AND RESPIRATORY INTEGRATION

Tonic pulmonary stretch receptor feedback modulates both eupnea and gasping in an in situ rat preparation

Department of Physiology, Dartmouth Medical School, Dartmouth Hitchcock Medical Center, Borwell Building, Lebanon, New Hampshire 03756

Submitted 4 March 2003 ; accepted in final form 5 March 2003

The perfused in situ juvenile rat preparation produces phrenic discharge patterns comparable to eupnea and gasping in vivo. These ventilatory patterns of eupnea and gasping differ in multiple aspects, including most prominently the rate of rise of inspiratory activity. Because gasping, but not eupnea, appeared similar after vagotomy in spontaneous breathing preparations, it has been assumed that gasping was unresponsive to afferent stimuli from pulmonary stretch receptors. In the present study, efferent activity of the phrenic nerve was recorded during eupnea and gasping in the in situ juvenile rat preparation. Gasping was induced in hypoxic-hypercapnia or ischemia. An increase in the pressure of tonic lung inflation from 1 to 10 cmH₂O caused a prolongation of the duration between phrenic bursts in both eupnea or gasping. Bilateral vagotomy eliminated these changes. We conclude that the neural substrate mediating the Hering-Breuer reflex is retained in the in situ preparation and that the brain stem circuitry generating the respiratory patterns responds to tonic activation of pulmonary stretch receptors in a similar manner in eupnea and gasping. These findings support the homology of eupnea-like phrenic discharge patterns in the reduced in situ preparation and eupnea in vivo and disprove the common supposition that gasping is insensitive to vagal afferent feedback from pulmonary stretch receptor mechanisms.

Hering-Breuer; slowly adapting pulmonary stretch receptors; vagus; eupnea; gasp

This article has been cited by other articles:

				C. Dubois, H. Houchi, M. Naassila, M. Daoust, and O. Pierrefiche Blunted response to low oxygen of rat respiratory network after perinatal ethanol exposure: involvement of inhibitory control J. Physiol., March 1, 2008; 586(5): 1413 - 1427. [Abstract] [Full Text] [PDF]

				M. B. Harris and W. M. St.-John Phasic pulmonary stretch receptor feedback modulates both eupnea and gasping in an in situ rat preparation Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R450 - R455. [Abstract] [Full Text] [PDF]

				T. A. Day and R. J. A. Wilson Specific carotid body chemostimulation is sufficient to elicit phrenic poststimulus frequency decline in a novel in situ dual-perfused rat preparation Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R532 - R544. [Abstract] [Full Text] [PDF]