Mechano-Electric Feedback in the Fish Heart

Simon M Patrick,Holly A Shiels,Ed White

doi:10.1371/journal.pone.0010548

Simon M Patrick, Holly A Shiels + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0010548

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Journal: PloS one	Publication Date: May 7, 2010
Citations: 34	License type: CC BY 4.0

Affiliation: University of Manchester, University of Leeds

Abstract

BackgroundMechanoelectric feedback (MEF) describes the modulation of electrical activity by mechanical activity. This may occur via the activation of mechanosensitive ion channels (MSCs). MEF has not previously been investigated in fish ventricular tissue even though fish can greatly increase ventricular end diastolic volume during exercise which should therefore provide a powerful mechanical stimulus for MEF.Methodology/Principal FindingWhen the ventricles of extrinsically paced, isolated working trout hearts were dilated by increasing afterload, monophasic action potential (MAP) duration was significantly shortened at 25% repolarisation, unaltered at 50% repolarisation and significantly lengthened at 90% repolarisation. This observation is consistent with the activation of cationic non-selective MSCs (MSCNSs). We then cloned the trout ortholog of TRPC1, a candidate MSCNS and confirmed its presence in the trout heart.Conclusions/SignificanceOur results have validated the use of MAP technology for the fish heart and suggest that, in common with amphibians and mammals, MEF operates in fish ventricular myocardium, possibly via the activation of mechanosensitive TRPC1 ion channels.

Highlights

Mechanoelectric feedback (MEF) is the process by which mechanical forces acting on the myocardium alter its electrical properties [1,2,3]
The upstroke times of mammalian monophasic action potential (MAP) are typically longer than those of intracellular action potential (AP) and we observed a similar effect in trout hearts
The upstroke of the MAP was slower than that of the intracellular AP, which is consistent with previous comparisons of MAPs and intracellular APs from mammals

Summary

Introduction

Mechanoelectric feedback (MEF) is the process by which mechanical forces acting on the myocardium alter its electrical properties [1,2,3]. When stretch provokes an initial shortening of the early AP repolarisation time course and an elongation of late repolarisation, it causes a cross over with regard to the stretched and unstretched AP time courses [2,17] Such an effect is consistent with the activation of MSCNS that have an equilibrium potential mid-way between the diastolic resting membrane potential and the peak of the AP upstroke [14,15]. Mechanoelectric feedback (MEF) describes the modulation of electrical activity by mechanical activity This may occur via the activation of mechanosensitive ion channels (MSCs).

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