Sodium/calcium exchange contributes to contraction and relaxation in failed human ventricular myocytes Export

@article{citeulike:4402451, abstract = {Defects in myocyte contraction and relaxation are key features of human heart failure. Sodium/calcium exchanger-mediated contribution to contraction and relaxation were separated from other mechanisms [L-type calcium current, sarco(endo)plasmic reticulum (SR) Ca2+-ATPase] based on voltage, temperature, and selective blockers. Rod-shaped left ventricular myocytes were isolated from failed human explants (n = 29) via perfusion with collagenase-containing Krebs solution. Action potentials using perforated patch and contractions using an edge detector were recorded at 0.5-1.5 Hz in Tyrode solution at 25{degrees}C and 37{degrees}C. Contraction duration was dependent on action potential (AP) duration at 37{degrees}C but not at 25{degrees}C, suggesting the role of the exchanger in relaxation and linking myocyte relaxation to the repolarization phase of the AP. Voltage-clamp experiments from [-]50 to +10 mV for 1,500 ms in Tyrode or Na+- and K+-free solutions after conditioning pulses triggered biphasic contractions that included a rapid SR-mediated component and a slower voltage-dependent exchanger-mediated component. We used thapsigargin to block the SR, which eliminated the rapid component, and we used an exchanger blocker, Kanebo 7943, which eliminated the slow component. The exchanger was shown to contribute to contraction through reverse-mode exchange, as well as to play a key role in relaxation of human ventricular myocytes.}, author = {Gaughan, John P. and Furukawa, Satoshi and Jeevanandam, Valluvan and Hefner, Colleen A. and Kubo, Hajime and Margulies, Kenneth B. and Mcgowan, Brian S. and Mattiello, Julian A. and Dipla, Konstantina and Piacentino, Valentino and Li, Siyun and Houser, Steven R.}, citeulike-article-id = {4402451}, citeulike-linkout-0 = {http://ajpheart.physiology.org/cgi/content/abstract/277/2/H714}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/10444498}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=10444498}, day = {1}, journal = {Am J Physiol Heart Circ Physiol}, keywords = {action, amphotericin, ap, apd, b, calcium, clamp, exchange, failed, failure, human, myocyte, ncx, patch, perforated, potential, sodium, ventricle}, month = {August}, number = {2}, pages = {H714--724}, posted-at = {2009-04-25 06:45:58}, priority = {2}, title = {Sodium/calcium exchange contributes to contraction and relaxation in failed human ventricular myocytes}, url = {http://ajpheart.physiology.org/cgi/content/abstract/277/2/H714}, volume = {277}, year = {1999} }

TY - JOUR ID - citeulike:4402451 L3 - citeulike-article-id:4402451 N2 - Defects in myocyte contraction and relaxation are key features of human heart failure. Sodium/calcium exchanger-mediated contribution to contraction and relaxation were separated from other mechanisms [L-type calcium current, sarco(endo)plasmic reticulum (SR) Ca2+-ATPase] based on voltage, temperature, and selective blockers. Rod-shaped left ventricular myocytes were isolated from failed human explants (n = 29) via perfusion with collagenase-containing Krebs solution. Action potentials using perforated patch and contractions using an edge detector were recorded at 0.5-1.5 Hz in Tyrode solution at 25{degrees}C and 37{degrees}C. Contraction duration was dependent on action potential (AP) duration at 37{degrees}C but not at 25{degrees}C, suggesting the role of the exchanger in relaxation and linking myocyte relaxation to the repolarization phase of the AP. Voltage-clamp experiments from [-]50 to +10 mV for 1,500 ms in Tyrode or Na+- and K+-free solutions after conditioning pulses triggered biphasic contractions that included a rapid SR-mediated component and a slower voltage-dependent exchanger-mediated component. We used thapsigargin to block the SR, which eliminated the rapid component, and we used an exchanger blocker, Kanebo 7943, which eliminated the slow component. The exchanger was shown to contribute to contraction through reverse-mode exchange, as well as to play a key role in relaxation of human ventricular myocytes. IS - 2 JF - Am J Physiol Heart Circ Physiol EP - 724 TI - Sodium/calcium exchange contributes to contraction and relaxation in failed human ventricular myocytes VL - 277 SP - H714 KW - action KW - amphotericin KW - ap KW - apd KW - b KW - calcium KW - clamp KW - exchange KW - failed KW - failure KW - human KW - myocyte KW - ncx KW - patch KW - perforated KW - potential KW - sodium KW - ventricle AU - Gaughan, John AU - Furukawa, Satoshi AU - Jeevanandam, Valluvan AU - Hefner, Colleen AU - Kubo, Hajime AU - Margulies, Kenneth AU - Mcgowan, Brian AU - Mattiello, Julian AU - Dipla, Konstantina AU - Piacentino, Valentino AU - Li, Siyun AU - Houser, Steven PY - 1999/08/01/ UR - http://ajpheart.physiology.org/cgi/content/abstract/277/2/H714 ER -