Characterization of Ca2+release channels in fetal and adult rat hearts

V. Ramesh, Mitchell Kresch, A. M. Katz, Han Kim Do Han Kim

Research output: Contribution to journalArticle

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Abstract

The goal of this study was to characterize the Ca2+-release channel in whole homogenates of left (LV) and right ventricles (RV) of fetal (22 days in gestation) and adult Sprague-Dawley rat hearts using [3H]ryanodine binding and 45Ca2+ fluxes. Although many features of the Ca2+-release channels were similar in fetal and adult hearts, biochemical assays revealed quantitative differences. Similar properties include 1) Ca2+-sensitive cooperative ryanodine binding to Ca2+-release channel, measured as Ca2+ concentration for half-maximal activation (fetal LV: 0.13 ± 0.02 μM; adult LV: 0.15 ± 0.02 μM) and Hill coefficient (fetal LV: 2.5 ± 0.9; adult LV: 2.7 ± 0.5), and 2) caffeine-sensitive ryanodine binding, measured as the percent increase in ryanodine binding induced by caffeine (fetal LV: 148.8 ± 16.9% vs. adult LV: 171.4 ± 34.9%). The distinguishing property was the lower Ca2+-release channel density in the fetal heart (LV: 0.22 ± 0.03 pmol/mg protein) compared with adult heart (LV: 0.59 ± 0.04 pmol/mg protein; P < 0.05), as determined by [3H]ryanodine binding. The lower density of Ca2+-release channel is supported by the finding that there is very low ryanodine-sensitive oxalate-supported 45Ca2+ uptake in the fetal heart. The tested characteristics of the Ca2+-release channel were similar between LV and RV in both fetal and adult rat hearts. Our results indicate that expression of Ca2+-release channels in sarcoplasmic reticulum increases during postnatal growth in the rat heart. This is consistent with previous physiological reports that Ca2+ available for excitation-contraction coupling in the fetal heart is derived mainly from transsarcolemmal Ca2+ influx.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume269
Issue number3 38-3
StatePublished - Jan 1 1995

Fingerprint

Ryanodine
Fetal Heart
heart
calcium
rats
Heart Ventricles
Caffeine
Excitation Contraction Coupling
Oxalates
caffeine
Sarcoplasmic Reticulum
Sprague Dawley Rats
Proteins
sarcoplasmic reticulum
Pregnancy
oxalates
Growth
cooperatives
proteins
pregnancy

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

@article{553ceefd70c1411ba3f6a56837d6d08d,
title = "Characterization of Ca2+release channels in fetal and adult rat hearts",
abstract = "The goal of this study was to characterize the Ca2+-release channel in whole homogenates of left (LV) and right ventricles (RV) of fetal (22 days in gestation) and adult Sprague-Dawley rat hearts using [3H]ryanodine binding and 45Ca2+ fluxes. Although many features of the Ca2+-release channels were similar in fetal and adult hearts, biochemical assays revealed quantitative differences. Similar properties include 1) Ca2+-sensitive cooperative ryanodine binding to Ca2+-release channel, measured as Ca2+ concentration for half-maximal activation (fetal LV: 0.13 ± 0.02 μM; adult LV: 0.15 ± 0.02 μM) and Hill coefficient (fetal LV: 2.5 ± 0.9; adult LV: 2.7 ± 0.5), and 2) caffeine-sensitive ryanodine binding, measured as the percent increase in ryanodine binding induced by caffeine (fetal LV: 148.8 ± 16.9{\%} vs. adult LV: 171.4 ± 34.9{\%}). The distinguishing property was the lower Ca2+-release channel density in the fetal heart (LV: 0.22 ± 0.03 pmol/mg protein) compared with adult heart (LV: 0.59 ± 0.04 pmol/mg protein; P < 0.05), as determined by [3H]ryanodine binding. The lower density of Ca2+-release channel is supported by the finding that there is very low ryanodine-sensitive oxalate-supported 45Ca2+ uptake in the fetal heart. The tested characteristics of the Ca2+-release channel were similar between LV and RV in both fetal and adult rat hearts. Our results indicate that expression of Ca2+-release channels in sarcoplasmic reticulum increases during postnatal growth in the rat heart. This is consistent with previous physiological reports that Ca2+ available for excitation-contraction coupling in the fetal heart is derived mainly from transsarcolemmal Ca2+ influx.",
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Characterization of Ca2+release channels in fetal and adult rat hearts. / Ramesh, V.; Kresch, Mitchell; Katz, A. M.; Do Han Kim, Han Kim.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 269, No. 3 38-3, 01.01.1995.

Research output: Contribution to journalArticle

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