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Reduction of I(Ca,L) and I(to1) density in hypertrophied right ventricular cells by simulated high altitude in adult rats.
J Mol Cell Cardiol. 1997 Jan; 29(1):193-206.JM

Abstract

The present paper describes the effect of a simulated hypobaric condition (at the altitude of 4500 m) on morphological characteristics and on some ionic currents in ventricular cells of adult rats. According to current data, chronic high-altitude exposure led to mild right ventricular hypertrophy. Increase in right ventricular weight appeared to be due wholly or partly to an enlargement of myocytes. The whole-cell patch-clamp technique was used and this confirmed, by cell capacitance measurement, that chronic high-altitude exposure induced an increase in the size of the right ventricular cells. Hypertrophied cells showed prolongation of action potential (AP). Four ionic currents, playing a role along with many others in the precise balance of inward and outward currents that control the duration of cardiac AP, were investigated. We report a significant decrease in the transient outward (I(to1)) and in the L-type calcium current (I(Ca,L)) densities while there was no significant difference in the delayed rectifier current (I(K)) or in the inward rectifier current (I(K1)) densities in hypertrophied right ventricular cells compared to control cells. At a given potential the decrease in I(to 1) density was relatively more important than the decrease in I(Ca,L) density. In both cell types, all the currents displayed the same voltage dependence. The inactivation kinetics of I(to 1) and I(Ca,L) or the steady-state activation and inactivation relationships were not significantly modified by chronic high-altitude exposure. We conclude that chronic high-altitude exposure induced true right ventricular myocyte hypertrophy and that the decrease in I(to 1) density might account for the lengthened action potential, or have a partial effect.

Authors+Show Affiliations

Laboratoire de Physiologie des Eléments Excitables (UMR CNRS 5578), Université Lyon I, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9040034

Citation

Chouabe, C, et al. "Reduction of I(Ca,L) and I(to1) Density in Hypertrophied Right Ventricular Cells By Simulated High Altitude in Adult Rats." Journal of Molecular and Cellular Cardiology, vol. 29, no. 1, 1997, pp. 193-206.
Chouabe C, Espinosa L, Megas P, et al. Reduction of I(Ca,L) and I(to1) density in hypertrophied right ventricular cells by simulated high altitude in adult rats. J Mol Cell Cardiol. 1997;29(1):193-206.
Chouabe, C., Espinosa, L., Megas, P., Chakir, A., Rougier, O., Freminet, A., & Bonvallet, R. (1997). Reduction of I(Ca,L) and I(to1) density in hypertrophied right ventricular cells by simulated high altitude in adult rats. Journal of Molecular and Cellular Cardiology, 29(1), 193-206.
Chouabe C, et al. Reduction of I(Ca,L) and I(to1) Density in Hypertrophied Right Ventricular Cells By Simulated High Altitude in Adult Rats. J Mol Cell Cardiol. 1997;29(1):193-206. PubMed PMID: 9040034.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reduction of I(Ca,L) and I(to1) density in hypertrophied right ventricular cells by simulated high altitude in adult rats. AU - Chouabe,C, AU - Espinosa,L, AU - Megas,P, AU - Chakir,A, AU - Rougier,O, AU - Freminet,A, AU - Bonvallet,R, PY - 1997/1/1/pubmed PY - 1997/1/1/medline PY - 1997/1/1/entrez SP - 193 EP - 206 JF - Journal of molecular and cellular cardiology JO - J Mol Cell Cardiol VL - 29 IS - 1 N2 - The present paper describes the effect of a simulated hypobaric condition (at the altitude of 4500 m) on morphological characteristics and on some ionic currents in ventricular cells of adult rats. According to current data, chronic high-altitude exposure led to mild right ventricular hypertrophy. Increase in right ventricular weight appeared to be due wholly or partly to an enlargement of myocytes. The whole-cell patch-clamp technique was used and this confirmed, by cell capacitance measurement, that chronic high-altitude exposure induced an increase in the size of the right ventricular cells. Hypertrophied cells showed prolongation of action potential (AP). Four ionic currents, playing a role along with many others in the precise balance of inward and outward currents that control the duration of cardiac AP, were investigated. We report a significant decrease in the transient outward (I(to1)) and in the L-type calcium current (I(Ca,L)) densities while there was no significant difference in the delayed rectifier current (I(K)) or in the inward rectifier current (I(K1)) densities in hypertrophied right ventricular cells compared to control cells. At a given potential the decrease in I(to 1) density was relatively more important than the decrease in I(Ca,L) density. In both cell types, all the currents displayed the same voltage dependence. The inactivation kinetics of I(to 1) and I(Ca,L) or the steady-state activation and inactivation relationships were not significantly modified by chronic high-altitude exposure. We conclude that chronic high-altitude exposure induced true right ventricular myocyte hypertrophy and that the decrease in I(to 1) density might account for the lengthened action potential, or have a partial effect. SN - 0022-2828 UR - https://www.unboundmedicine.com/medline/citation/9040034/Reduction_of_I_CaL__and_I_to1__density_in_hypertrophied_right_ventricular_cells_by_simulated_high_altitude_in_adult_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2828(96)90264-3 DB - PRIME DP - Unbound Medicine ER -