AJP - Regulatory, Integrative and Comparative Physiology, Vol 272, Issue 2 497-R508, Copyright © 1997 by American Physiological Society

ARTICLES

Role of pulmonary stretch receptor feedback in control of episodic breathing in the bullfrog

R. Kinkead and W. K. Milsom
Department of Zoology, University of British Columbia, Vancouver, Canada. kinkeadr@svm.vetmed.wisc.edu

This study compared the "fictive" breathing patterns of decerebrate, paralyzed, unidirectionally ventilated bullfrogs in which pulmonary stretch receptor (PSR) feedback was either absent bilateral vagotomy), maintained constant at different levels (tonic) or oscillated with each fictive breath (phasic) under different levels of hypoxic or CO2-related respiratory drive. Tonic and phasic PSR feedback had identical effects on the fictive breathing pattern; decreasing PSR feedback increased the peak integrated trigeminal electroneurogram recordings and decreased breathing frequency. The effects of bilateral vagotomy and lung deflation to 0 cmH2O on breathing pattern were identical. Although hypoxia (fractional concentration of O2 in air = 0.06) had no significant effect on fictive breathing, ventilating frogs with increasing CO2 levels (fractional CO2 concentration in inspired air range: 0.00-0.03) increased the number of breaths in each fictive breathing episode, and this effect was potentiated by PSR feedback. Whenever respiratory drive was increased, regardless of the method (increase in PSR feedback or chemoreceptor drive), occasional single breaths were replaced by breathing episodes, indicating that the mechanisms responsible for the clustering of the breaths and the onset/termination of breathing episodes are not dependent on either input alone.

This article has been cited by other articles:

				C. R. Noronha-de-Souza, K. C. Bicego, G. Michel, M. L. Glass, L. G. S. Branco, and L. H. Gargaglioni Locus coeruleus is a central chemoreceptive site in toads Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2006; 291(4): R997 - R1006. [Abstract] [Full Text] [PDF]

				S. M. Johnson and R. J. Creighton Spinal cord injury-induced changes in breathing are not due to supraspinal plasticity in turtles (Pseudemys scripta) Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2005; 289(6): R1550 - R1561. [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]

				R. Kinkead, O. Belzile, and R. Gulemetova Serotonergic modulation of respiratory motor output during tadpole development J Appl Physiol, September 1, 2002; 93(3): 936 - 946. [Abstract] [Full Text] [PDF]

				C. S. Torgerson, M. J. Gdovin, R. Brandt, and J. E. Remmers Location of central respiratory chemoreceptors in the developing tadpole Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2001; 280(4): R921 - R928. [Abstract] [Full Text] [PDF]

				C. E. Sanders and W. K. Milsom THE effects of tonic lung inflation on ventilation in the American bullfrog Rana catesbeiana Shaw J. Exp. Biol., January 8, 2001; 204(15): 2647 - 2656. [Abstract] [Full Text] [PDF]

				E. W. Taylor, D. Jordan, and J. H. Coote Central Control of the Cardiovascular and Respiratory Systems and Their Interactions in Vertebrates Physiol Rev, July 1, 1999; 79(3): 855 - 916. [Abstract] [Full Text] [PDF]