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: 289/2/R326    most recent 00708.2004v1 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 ISI 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 ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Kvadsheim, P. H. Articles by Blix, A. S. Search for Related Content PubMed PubMed Citation Articles by Kvadsheim, P. H. Articles by Blix, A. S.

CALL FOR PAPERS
Physiology and Pharmacology of Temperature Regulation

Inhibition of shivering in hypothermic seals during diving

Department of Arctic Biology and Institute of Medical Biology, University of Tromsø, Tromsø, Norway

Submitted 18 October 2004 ; accepted in final form 3 March 2005

The mammalian response to hypothermia is increased metabolic heat production, usually by way of muscular activity, such as shivering. Seals, however, have been reported to respond to diving with hypothermia, which in other mammals under other circumstances would have elicited vigorous shivering. In the diving situation, shivering could be counterproductive, because it obviously would increase oxygen consumption and therefore reduce diving capacity. We have measured the electromyographic (EMG) activity of three different muscles and the rectal and brain temperature of hooded seals (Cystophora cristata) while they were exposed to low ambient temperatures in a climatic chamber and while they performed a series of experimental dives in cold water. In air, the seals had a normal mammalian shivering response to cold. Muscles were recruited in a sequential manner until body temperature stopped dropping. Shivering was initiated when rectal temperature fell below 35.3 ± 0.6°C (n = 6). In the hypothermic diving seal, however, the EMG activity in all of the muscles that had been shivering vigorously before submergence was much reduced, or stopped altogether, whereas it increased again upon emergence but was again reduced if diving was repeated. We conclude that shivering is inhibited during diving to allow a decrease in body temperature whereby oxygen consumption is decreased and diving capacity is extended.

hooded seal Cystophora cristata; shivering electromyogram; body core temperature; thermoregulation

This article has been cited by other articles:

				A. A. Romanovsky Thermoregulation: some concepts have changed. Functional architecture of the thermoregulatory system Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R37 - R46. [Abstract] [Full Text] [PDF]

				P. B. Persson Temperature control: from molecular insights, regulation in king penguins and diving seals, to studies in humans Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R512 - R514. [Full Text] [PDF]