QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Butler, P. J. Articles by Taylor, E. W. Search for Related Content PubMed PubMed Citation Articles by Butler, P. J. Articles by Taylor, E. W.

Journal of Experimental Biology, Vol 63, Issue 1 117-130, Copyright © 1975 by Company of Biologists

JOURNAL ARTICLES

The effect of progressive hypoxia on respiration in the dogfish (scyliorhinus canicula) at different seasonal temperatures

PJ Butler and EW Taylor

1. Dogfish were acclimated to 7, 12 or 17 degrees C and exposed to progressive hypoxia at the temperature to which they had been acclimated. During normoxia, the Q10 values for oxygen uptake, heart rate, cardiac output and respiratory frequency over the full 10 degrees C range were: 2.1, 2.1, 2.1 and 2.5 respectively. Increased acclimation temperature had no effect on cardiac stroke volume or systemic vascular resistance, although there was a decrease in branchial vascular resistance, pHa and pHv. 2. Progressive hypoxia had no effect on heart rate or oxygen uptake at 7 degrees C, whereas at 12 degrees C and 17 degrees C there was bradycardia, and a reduction in O2 uptake, with the critical oxygen tension for both variables being higher at the higher temperature. Cardiac stroke volume increased during hypoxia at each temperature, such that cardiac output did not change significantly at 12 and 17 degrees C. Neither pHa nor pHv changed significantly during hypoxia at any of the three temperatures. 3. The influence of acclimation temperatures on experimental results from poikilotherms is pointed out. Previously-published results show quantitative differences. 4. The significance of the present results with respect to the functioning and location of oxygen receptors is discussed. It is argued that as the metabolic demand and critical oxygen tension of the whole animal are increased at high acclimation temperatures the same must be the case with the oxygen receptor. This would raise the stimulation threshold and could account for the bradycardia seen during hypoxia becoming manifest at higher values of PI,O2, Pa,O2 and Pv,O2 as the acclimation temperature is raised.

This article has been cited by other articles:

				A. P. Farrell Tribute to P. L. Lutz: a message from the heart - why hypoxic bradycardia in fishes? J. Exp. Biol., May 15, 2007; 210(10): 1715 - 1725. [Abstract] [Full Text] [PDF]

				J. Sollid, R. E. Weber, and G. E. Nilsson Temperature alters the respiratory surface area of crucian carp Carassius carassius and goldfish Carassius auratus J. Exp. Biol., March 15, 2005; 208(6): 1109 - 1116. [Abstract] [Full Text] [PDF]

				K.-O. Stenslokken, L. Sundin, G. M. C. Renshaw, and G. E. Nilsson Adenosinergic and cholinergic control mechanisms during hypoxia in the epaulette shark (Hemiscyllium ocellatum), with emphasis on branchial circulation J. Exp. Biol., December 1, 2004; 207(25): 4451 - 4461. [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]