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Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles
Published on: October 15, 2014
Cardiac T-type Ca(2+) channels in the heart
Kyoichi Ono1, Toshihiko Iijima
1Department of Cell Physiology, Akita University School of Medicine, Akita 010-8543, Japan. onok@med.akita-u.ac.jp
Journal of Molecular and Cellular Cardiology
|September 5, 2009
Summary
Cardiac T-type calcium channels (CaV3.1, CaV3.2) are crucial in heart development and function. Their re-expression in disease contributes to pathological cardiac hypertrophy via calcineurin/NFAT signaling.
Area of Science:
- Cardiology
- Molecular Biology
- Electrophysiology
Background:
- Two Ca(2+) channels, L-type and T-type, exist in cardiac myocytes.
- L-type channels are key for excitation-contraction coupling and pacemaker activity.
- T-type channel roles are diverse, varying by species, age, and disease, with isoforms Ca(V)3.1 and Ca(V)3.2 expressed during development but diminishing in adults.
Purpose of the Study:
- To review current knowledge on cardiac T-type Ca(2+) channels.
- To discuss their pathophysiological significance in the heart, particularly in hypertrophy.
Main Methods:
- Literature review of studies on cardiac T-type Ca(2+) channels.
- Analysis of T-type channel expression and function in normal and pathological conditions.
- Examination of regulatory mechanisms of T-type channel expression.
Main Results:
- T-type channels are mainly in the adult heart's conduction system, aiding sinoatrial node depolarization.
- Re-expression occurs in pathological states (hypertrophy, heart failure), contributing to abnormal electrical activity.
- Ca(V)3.2 influx triggers calcineurin/NFAT signaling, promoting pathological cardiac hypertrophy.
Conclusions:
- Cardiac T-type Ca(2+) channels have diverse roles, especially in pathological hypertrophy.
- Understanding their regulation (NRSE-NRSF, MAP kinases, Csx/Nkx2.5) is vital.
- Targeting T-type channels may offer therapeutic strategies for heart disease.
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