The role of adrenaline as a modulator of cardiac performance in three Notothenioid fishes

TY - ABST

T1 - The role of adrenaline as a modulator of cardiac performance in three Notothenioid fishes

AU - Skov, Peter Vilhelm

AU - Bushnell, P.

AU - Tirsgaard, Bjørn

AU - Steffensen, John Fleng

N1 - Udgivelsesdato: July 2008 Volumne: 150

PY - 2008

Y1 - 2008

N2 - The present work was performed to test the hypothesis that Antarctic teleosts rely mostly on cholinergic inhibition to modulate cardiac performance. Isometric muscle preparations were used to examine the inotropic and chronotropic properties of the ventricle and atrium in three Antarctic teleosts. The importance of adrenaline as a neurotransmitter was evaluated through a series of dose-response experiments in conjunction with increasing pacing frequencies, to establish whether adrenaline modulated force of contraction and the maximum frequency with which tissues could contract. Only in Chaenocephalus aceratus did increasing adrenaline have an effect on chronotropic properties, but in no tissues did increasing adrenaline enable tissues to operate at higher pacing frequencies. Atrial tissues could consistently be paced at higher frequencies than their ventricular counterparts. There was a three-fold difference in force of contraction at the lowest pacing frequency and tonic adrenaline level between species. Increasing adrenaline enhanced peak tension for all ventricular tissues, yet the response was highly species specific, increasing force of contraction two to four-fold. Only in one species did adrenaline appear to enhance force of contraction for atrial muscle. The study finds that adrenaline modulates ventricular inotropic properties in all species. For Notothenia coriiceps the regulation of power production purely by adrenergic stimulation appeared most beneficial, while for N. microlepidota and C. aceratus a combination of pacing frequency and adrenaline yielded the greatest response. The results are discussed with respect to the life-style, temperature and cardiac morphometry of the species investigated.

AB - The present work was performed to test the hypothesis that Antarctic teleosts rely mostly on cholinergic inhibition to modulate cardiac performance. Isometric muscle preparations were used to examine the inotropic and chronotropic properties of the ventricle and atrium in three Antarctic teleosts. The importance of adrenaline as a neurotransmitter was evaluated through a series of dose-response experiments in conjunction with increasing pacing frequencies, to establish whether adrenaline modulated force of contraction and the maximum frequency with which tissues could contract. Only in Chaenocephalus aceratus did increasing adrenaline have an effect on chronotropic properties, but in no tissues did increasing adrenaline enable tissues to operate at higher pacing frequencies. Atrial tissues could consistently be paced at higher frequencies than their ventricular counterparts. There was a three-fold difference in force of contraction at the lowest pacing frequency and tonic adrenaline level between species. Increasing adrenaline enhanced peak tension for all ventricular tissues, yet the response was highly species specific, increasing force of contraction two to four-fold. Only in one species did adrenaline appear to enhance force of contraction for atrial muscle. The study finds that adrenaline modulates ventricular inotropic properties in all species. For Notothenia coriiceps the regulation of power production purely by adrenergic stimulation appeared most beneficial, while for N. microlepidota and C. aceratus a combination of pacing frequency and adrenaline yielded the greatest response. The results are discussed with respect to the life-style, temperature and cardiac morphometry of the species investigated.

U2 - 10.1016/j.cbpa.2008.04.193

DO - 10.1016/j.cbpa.2008.04.193

M3 - Conference abstract in journal

SN - 1095-6433

VL - 150

SP - S97-S98

JO - Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology

JF - Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology

IS - 3, Supplement

M1 - A5.3

T2 - Annual Main Meeting of the Society of Experimental Biology

Y2 - 6 July 2008 through 10 July 2010

ER -