Developmental changes in the contributions of the Ca2+ channels and Na+-Ca2+ exchanger to contractions in rabbit cardiac ventricular myocytes

Thomas Chin, G. Christiansen, J. Caldwell, E. Prince

Research output: Contribution to journalArticle

Abstract

Sarcolemmal Ca2influx is considered more important for contractions in immature vs mature hearts. To measure developmental changes in the contributions of the Ca2+ channels and 2+-Ca2+ exchanger to contractions, intracellular Ca2transients were measured in field-stimulated ventricular myocytes from 1 -4 day neonatal and 4-6 week adult New Zealand White Rabbits at 24° C. The cells were loaded for 10 minutes with 10 uM indo-1 AM, and washed in normal Tyrode's solution before study. After inhibiting the sarcoplasmic reticulum (SR) with 500 nM thapsigargin and 10 pM ryanodine, Ca2+ transients were unchanged in 22 neonatal cells, but decreased in 20 adult cells to 88.8+3.4% of baseline (mean+SEM, P<0.01). With the SR_and .Ca2+_channejs inhibited (thapsigargin, ryanodine + 20 uM nifedipine), Ca2+ transients from reverse 2+-Ca2+ exchange were larger in 5 neonatal compared to 7 adult cells (61 4+0.7% vs. 11.6+4.9%, P<0 001). With the SRCa2" channels and 2+-Ca2+ exchanger inhibited (thapsigargin, ryanodine + 5 mM Ni2+), Ca2+ transients were eliminated in cells from both age groups. In conclusion, the 2+-Ca2+ exchanger is responsible during contractions for =60% of the rise in intracellular Ca2+ in neonatal vs. = 12% of the rise in adult rabbit myocytes The relative contribution of the Ca2+ channels vs. 2+-Ca2+ exchanger is smaller in the neonatal cells, but 6-fold larger in the adult cells.

Original languageEnglish (US)
JournalFASEB Journal
Volume10
Issue number3
StatePublished - Dec 1 1996

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Ryanodine
Thapsigargin
Cardiac Myocytes
Rabbits
Nifedipine
Sarcoplasmic Reticulum
Muscle Cells
Scanning electron microscopy
Age Groups

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

Cite this

@article{dbf96047822e44b199a6b9632afb96c1,
title = "Developmental changes in the contributions of the Ca2+ channels and Na+-Ca2+ exchanger to contractions in rabbit cardiac ventricular myocytes",
abstract = "Sarcolemmal Ca2influx is considered more important for contractions in immature vs mature hearts. To measure developmental changes in the contributions of the Ca2+ channels and 2+-Ca2+ exchanger to contractions, intracellular Ca2transients were measured in field-stimulated ventricular myocytes from 1 -4 day neonatal and 4-6 week adult New Zealand White Rabbits at 24° C. The cells were loaded for 10 minutes with 10 uM indo-1 AM, and washed in normal Tyrode's solution before study. After inhibiting the sarcoplasmic reticulum (SR) with 500 nM thapsigargin and 10 pM ryanodine, Ca2+ transients were unchanged in 22 neonatal cells, but decreased in 20 adult cells to 88.8+3.4{\%} of baseline (mean+SEM, P<0.01). With the SR_and .Ca2+_channejs inhibited (thapsigargin, ryanodine + 20 uM nifedipine), Ca2+ transients from reverse 2+-Ca2+ exchange were larger in 5 neonatal compared to 7 adult cells (61 4+0.7{\%} vs. 11.6+4.9{\%}, P<0 001). With the SRCa2{"} channels and 2+-Ca2+ exchanger inhibited (thapsigargin, ryanodine + 5 mM Ni2+), Ca2+ transients were eliminated in cells from both age groups. In conclusion, the 2+-Ca2+ exchanger is responsible during contractions for =60{\%} of the rise in intracellular Ca2+ in neonatal vs. = 12{\%} of the rise in adult rabbit myocytes The relative contribution of the Ca2+ channels vs. 2+-Ca2+ exchanger is smaller in the neonatal cells, but 6-fold larger in the adult cells.",
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Developmental changes in the contributions of the Ca2+ channels and Na+-Ca2+ exchanger to contractions in rabbit cardiac ventricular myocytes. / Chin, Thomas; Christiansen, G.; Caldwell, J.; Prince, E.

In: FASEB Journal, Vol. 10, No. 3, 01.12.1996.

Research output: Contribution to journalArticle

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T1 - Developmental changes in the contributions of the Ca2+ channels and Na+-Ca2+ exchanger to contractions in rabbit cardiac ventricular myocytes

AU - Chin, Thomas

AU - Christiansen, G.

AU - Caldwell, J.

AU - Prince, E.

PY - 1996/12/1

Y1 - 1996/12/1

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AB - Sarcolemmal Ca2influx is considered more important for contractions in immature vs mature hearts. To measure developmental changes in the contributions of the Ca2+ channels and 2+-Ca2+ exchanger to contractions, intracellular Ca2transients were measured in field-stimulated ventricular myocytes from 1 -4 day neonatal and 4-6 week adult New Zealand White Rabbits at 24° C. The cells were loaded for 10 minutes with 10 uM indo-1 AM, and washed in normal Tyrode's solution before study. After inhibiting the sarcoplasmic reticulum (SR) with 500 nM thapsigargin and 10 pM ryanodine, Ca2+ transients were unchanged in 22 neonatal cells, but decreased in 20 adult cells to 88.8+3.4% of baseline (mean+SEM, P<0.01). With the SR_and .Ca2+_channejs inhibited (thapsigargin, ryanodine + 20 uM nifedipine), Ca2+ transients from reverse 2+-Ca2+ exchange were larger in 5 neonatal compared to 7 adult cells (61 4+0.7% vs. 11.6+4.9%, P<0 001). With the SRCa2" channels and 2+-Ca2+ exchanger inhibited (thapsigargin, ryanodine + 5 mM Ni2+), Ca2+ transients were eliminated in cells from both age groups. In conclusion, the 2+-Ca2+ exchanger is responsible during contractions for =60% of the rise in intracellular Ca2+ in neonatal vs. = 12% of the rise in adult rabbit myocytes The relative contribution of the Ca2+ channels vs. 2+-Ca2+ exchanger is smaller in the neonatal cells, but 6-fold larger in the adult cells.

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