The role of adrenaline as a modulator of cardiac performance in three Notothenioid fishes
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. T...
| Published in: | Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology |
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| Main Authors: | , , , |
| Format: | Conference Object |
| Language: | English |
| Published: |
2008
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| Subjects: | |
| Online Access: | https://curis.ku.dk/portal/da/publications/the-role-of-adrenaline-as-a-modulator-of-cardiac-performance-in-three-notothenioid-fishes(94573000-c15f-11df-825b-000ea68e967b).html https://doi.org/10.1016/j.cbpa.2008.04.193 |
| Summary: | 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. |
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