%0 Journal Article %1 Bret_2004_e1 %A Brette, Fabien %A Sall�, Laurent %A Orchard, Clive H %D 2004 %J Circ. Res. %K 15192026 Animals, Calcium Calcium, Cardiac, Cell Cells, Channels, Conductivity, Cultu, Electric Gov't, Heart L-Type, Membrane, Myocytes, Non-U.S. Patch-Clamp Rats, Research Reticulum, Sarcoplasmic Support, Techniques, Ventricles, Wistar, red, %N 1 %P e1--e7 %R 10.1161/01.RES.0000135547.53927.F6 %T Differential modulation of L-type Ca$^2+$ current by SR Ca$^2+$ release at the T-tubules and surface membrane of rat ventricular myocytes. %U http://dx.doi.org/10.1161/01.RES.0000135547.53927.F6 %V 95 %X We have characterized modulation of ICa by Ca$^2+$ at the t-tubules (ie, in control cells) and surface sarcolemma (ie, in detubulated cells) of cardiac ventricular myocytes, using the whole-cell patch clamp technique to record ICa. ICa inactivation was significantly slower in detubulated cells than in control cells (27.1+/-7.8 ms, n=22, versus 16.4+/-7.9 ms, n=22; P<0.05). In atrial myocytes, which lack t-tubules, ICa inactivation was not changed by the treatment used to produce detubulation. In the presence of ryanodine or BAPTA, or when Ba2+ was used as the charge carrier, the rate of inactivation was not significantly different in control and detubulated cells. Frequency-dependent facilitation occurred in control cells but not in detubulated cells, and was abolished by ryanodine. These results suggest that Ca$^2+$ released from the SR has a greater effect on ICa in the t-tubules than at the surface sarcolemma. This does not appear to be due to differences in local Ca$^2+$ release from the SR, because the gain of Ca$^2+$ release was not significantly different in control and detubulated cells. These data suggest that the t-tubules are a key site for the regulation of transsarcolemmal Ca$^2+$ flux by Ca$^2+$ release from the SR; this could play a role in altered Ca$^2+$ homeostasis in pathological conditions. The full text of this article is available online at http://circres.ahajournals.org.

@article{Bret_2004_e1, abstract = {We have characterized modulation of ICa by {C}a$^{2+}$ at the t-tubules (ie, in control cells) and surface sarcolemma (ie, in detubulated cells) of cardiac ventricular myocytes, using the whole-cell patch clamp technique to record ICa. ICa inactivation was significantly slower in detubulated cells than in control cells (27.1+/-7.8 ms, n=22, versus 16.4+/-7.9 ms, n=22; P<0.05). In atrial myocytes, which lack t-tubules, ICa inactivation was not changed by the treatment used to produce detubulation. In the presence of ryanodine or BAPTA, or when Ba2+ was used as the charge carrier, the rate of inactivation was not significantly different in control and detubulated cells. Frequency-dependent facilitation occurred in control cells but not in detubulated cells, and was abolished by ryanodine. These results suggest that {C}a$^{2+}$ released from the SR has a greater effect on ICa in the t-tubules than at the surface sarcolemma. This does not appear to be due to differences in local {C}a$^{2+}$ release from the SR, because the gain of {C}a$^{2+}$ release was not significantly different in control and detubulated cells. These data suggest that the t-tubules are a key site for the regulation of transsarcolemmal {C}a$^{2+}$ flux by {C}a$^{2+}$ release from the SR; this could play a role in altered {C}a$^{2+}$ homeostasis in pathological conditions. The full text of this article is available online at http://circres.ahajournals.org.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Brette, Fabien and Sall�, Laurent and Orchard, Clive H}, biburl = {https://www.bibsonomy.org/bibtex/26f8109983d2366d41af05622185d72bd/hake}, description = {The whole bibliography file I use.}, doi = {10.1161/01.RES.0000135547.53927.F6}, file = {Bret_2004_e1.pdf:Bret_2004_e1.pdf:PDF}, interhash = {9d12b0dbf2cb5540c5193f2a6920d0bc}, intrahash = {6f8109983d2366d41af05622185d72bd}, journal = {Circ. Res.}, key = 226, keywords = {15192026 Animals, Calcium Calcium, Cardiac, Cell Cells, Channels, Conductivity, Cultu, Electric Gov't, Heart L-Type, Membrane, Myocytes, Non-U.S. Patch-Clamp Rats, Research Reticulum, Sarcoplasmic Support, Techniques, Ventricles, Wistar, red,}, month = Jul, number = 1, pages = {e1--e7}, pii = {01.RES.0000135547.53927.F6}, pmid = {15192026}, timestamp = {2009-06-03T11:21:06.000+0200}, title = {Differential modulation of L-type {C}a$^{2+}$ current by SR {C}a$^{2+}$ release at the T-tubules and surface membrane of rat ventricular myocytes.}, url = {http://dx.doi.org/10.1161/01.RES.0000135547.53927.F6}, volume = 95, year = 2004 }