DOI 10.1007/s00300-008-0522-0 ORIGINAL PAPER The role of adrenaline as a modulator of cardiac performance in two Antarctic fishes

Abstract The present work was performed to test the hypothesis that Antarctic teleosts rely mostly on cholinergic inhibition for autonomic modulation of the heart. The effects of adrenaline on the inotropic properties on paced, isometrically contracting muscle strips were examined in two distinct An...

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Bibliographic Details
Main Authors: Bjørn Tirsgaard, Æ John, Fleng Steffensen, Chaenocephalus Notothenia, P. V. Skov, B. Tirsgaard J. F. Steffensen, P. G. Bushnell
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Subjects:
Antarctic
Antarc*
Icefish
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.140.1078
http://www.mbl.ku.dk/JFSteffensen/PolarBiology%202008%20PVS.pdf
Description
Summary:Abstract The present work was performed to test the hypothesis that Antarctic teleosts rely mostly on cholinergic inhibition for autonomic modulation of the heart. The effects of adrenaline on the inotropic properties on paced, isometrically contracting muscle strips were examined in two distinct Antarctic teleosts, the haemoglobinless icefish Chaenocephalus aceratus and the red-blooded Notothenia coriiceps. All tissues examined revealed a negative forcefrequency relationship. Under baseline conditions C. aceratus contracted with a force twice as great as that of N. coriiceps. While the degree to which ventricular tissues responded to adrenaline varied between species, adrenergic stimulation significantly increases myocyte contraction force in this group of fishes. Contraction and relaxation times were not significantly affected by adrenaline concentration while absolute rates of contraction were. Adrenergic stimulation does not enable tissues to achieve higher contraction frequencies, but is shown to be a potent modulator of contraction force.

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