Effects of seasonal acclimatization on action potentials and sarcolemmal K+ currents in roach (Rutilus rutilus) cardiac myocytes.

  title={Effects of seasonal acclimatization on action potentials and sarcolemmal K+ currents in roach (Rutilus rutilus) cardiac myocytes.},
  author={Ahmed Badr and Minna Hassinen and Mohamed Abdel-Fattah El-Sayed and Matti Vornanen},
  journal={Comparative biochemistry and physiology. Part A, Molecular \& integrative physiology},
  • A. BadrM. Hassinen M. Vornanen
  • Published 1 March 2017
  • Environmental Science
  • Comparative biochemistry and physiology. Part A, Molecular & integrative physiology

Effects of seasonal acclimatization on thermal tolerance of inward currents in roach (Rutilus rutilus) cardiac myocytes

The response of sodium (INa) and calcium (ICa) currents in heat tolerance of cardiac excitability was examined in a eurythermic fish and the response of INa to seasonal acclimatization conforms to the TDEE hypothesis.

Electrical excitability of roach ( Rutilus rutilus) ventricular myocytes: effects of extracellular K+, temperature, and pacing frequency.

Although high [K+]o antagonizes the negative effects of high temperature on excitation threshold, the precipitous depression of the rate of AP upstroke and complete loss of excitability in some myocytes suggest that the combination of highTemperature and high [ K+]O will severely impair ventricular excitabilityIn roach.

Thermal acclimation and seasonal acclimatization: a comparative study of cardiac response to prolonged temperature change in shorthorn sculpin

The effects of seasonal acclimatization on cardiac responses to low temperatures are stronger than those of acclimation to similar temperatures in laboratory conditions, highlighting the importance of seasonal cues for cardiac remodelling in a eurythermal fish.

Repolarizing potassium currents in working myocardium of Japanese quail: Novel translational model for cardiac electrophysiology.

Small functional If current in sinoatrial pacemaker cells of the brown trout (Salmo trutta fario) heart despite strong expression of HCN channel transcripts.

The results strongly suggest that fH regulation in the brown trout heart is largely independent on If, and the presence and activity of HCN channels in the SA pacemaker cells and their putative role in heart rate regulation is examined.

Transcript expression of inward rectifier potassium channels of Kir2 subfamily in Arctic marine and freshwater fish species

The cardiac Kir2 composition seems to be dependent on both phylogenetic position and thermal preference of the fish.

Feeling the heat: source–sink mismatch as a mechanism underlying the failure of thermal tolerance

A modified hypothesis about high temperature-induced failure of electrically excitable tissues is discussed, and can explain a number of heat-induced effects, including reduced heart rate, reduced synaptic transmission between neurons and reduced impulse transfer from neurons to muscles.



Effects of seasonal acclimatization on temperature dependence of cardiac excitability in the roach, Rutilus rutilus

Seasonal acclimatization of the electrical excitability of the eurythermal roach increases pumping capacity of the roach heart by maximizing heart rate, but without compromising the stability of cardiac excitation.

Effect of thermal acclimation on action potentials and sarcolemmal K+ channels from Pacific bluefin tuna cardiomyocytes.

The results indicate the bluefin AP is relatively short compared with other teleosts, which may allow thebluefin heart to function at cold temperatures without the necessity for thermal compensation of APD.

Temperature-dependent expression of sarcolemmal K(+) currents in rainbow trout atrial and ventricular myocytes.

Results provide the first concrete evidence that K(+) channels of trout cardiac myocytes are adaptable units that provide means to regulate cardiac excitability and contractility as a function of temperature.

Responses of Action Potential and K+ Currents to Temperature Acclimation in Fish Hearts: Phylogeny or Thermal Preferences?

In Salmoniformes fish, the thermal plasticity of APD is strongly based on IKr, while other fish groups rely on both IKR and IK1, which is more plastic in eurythermal than in stenothermal fish species.

Acute heat tolerance of cardiac excitation in the brown trout (Salmo trutta fario)

Findings from different levels of biological organization strongly suggest that heat-dependent deterioration of Na+ channel function disturbs normal spread of electrical excitation over the heart, leading to progressive variability of cardiac rhythmicity, reduction of heart rate and finally cessation of the normal heartbeat.

Effect of temperature and temperature acclimation on the ryanodine sensitivity of the trout myocardium

The results suggest that the sarcoplamic reticulum calcium release channel of the trout myocardium is expressed but is not functionally involved in beat-to-beat regulation of contractility at either a low temperature (8 °C), or at routine physiological heart rate (>0.6 Hz).

Sarcolemmal Ca influx through L-type Ca channels in ventricular myocytes of a teleost fish.

  • M. Vornanen
  • Biology
    The American journal of physiology
  • 1997
The findings imply that Ca influx through L-type Ca channels can contribute significantly to the activation of contraction in the ventricular myocytes of fish heart.


Inotropic and chronotropic responsiveness of yellow perch and smallmouth bass hearts, following low temperature acclimation, was assessed with ventricle strips mounted for isometric force recording, suggesting an enhancement in calcium handling capabilities following acclimated to low temperature.

Maximum heart rate in brown trout (Salmo trutta fario) is not limited by firing rate of pacemaker cells.

It is strongly suggested that the frequency generator of the sinoatrial pacemaker cells does not limit fH at high temperatures in the brown trout in vivo.

The effect of temperature on spontaneous action potential discharge of the isolated sinus venosus from winter and summer plaice (Pleuronectes platessa)

The observed changes in pacemaker discharge rate were not influenced by the processes that determine the duration of the pacemaker diastolic depolarisation but were modulated by the channel events that give rise to the action potential.