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

First published online October 21, 2004
Journal of Experimental Biology 207, 4157-4164 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01251

This Article Figures Only Full Text 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 MacCormack, T. J. Articles by Driedzic, W. R. Search for Related Content PubMed PubMed Citation Articles by MacCormack, T. J. Articles by Driedzic, W. R.

Cardiorespiratory and tissue adenosine responses to hypoxia and reoxygenation in the short-horned sculpin Myoxocephalus scorpius

T. J. MacCormack and W. R. Driedzic^*

Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, Canada A1C 5S7

^* Author for correspondence (e-mail: wdriedzic{at}mun.ca)

Accepted 18 August 2004

Adenosine is a product of adenylate phosphate breakdown that can exert protective effects on tissues during energy limitation. Accumulation of cardiac adenosine under hypoxia is well documented in mammals but has not been shown in fish. Adenosine content was measured in heart and brain tissue from short-horned sculpin Myoxocephalus scorpius L. exposed to acute hypoxia and to graded hypoxia and reoxygenation at 8°C. Cardiorespiratory parameters were recorded along with plasma lactate, K⁺, Ca²⁺ and Na⁺ levels and their relationship to adenosine levels investigated. Sculpin exhibited a large bradycardia during hypoxia, with a concomitant drop in cardiac output that recovers fully with reoxygenation. Ventilation rate also declined with hypoxia, suggesting a depression of activity. Plasma lactate concentration was significantly elevated after 4 h at 2.0 mg l^-1 dissolved oxygen while K⁺ levels increased during acute hypoxia. Adenosine levels were maintained in heart under acute and graded hypoxia. Brain levels fluctuated under hypoxia and showed no change with reoxygenation. It is concluded that a depression of cardiac activity in conjunction with an adequate anaerobic metabolism allow sculpin to avoid excessive adenosine accumulation under conditions of moderate hypoxia. Cardiac adenosine levels decreased and plasma K⁺ levels and heart rate increased significantly at reoxygenation.

Key words: adenosine, fish heart, hypoxia, reoxygenation, short-horned sculpin, Myoxocephalus scorpius

This article has been cited by other articles:

				L. G. Eckerle, M. Lucassen, T. Hirse, and H. O. Portner Cold induced changes of adenosine levels in common eelpout (Zoarces viviparus): a role in modulating cytochrome c oxidase expression J. Exp. Biol., April 15, 2008; 211(8): 1262 - 1269. [Abstract] [Full Text] [PDF]

				T. J. MacCormack and W. R. Driedzic The impact of hypoxia on in vivo glucose uptake in a hypoglycemic fish, Myoxocephalus scorpius Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2007; 292(2): R1033 - R1042. [Abstract] [Full Text] [PDF]