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We have studied the molecular determinants of ion permeation through the TRPV4 channel (VRL-2, TRP12, VR-OAC, and OTRPC4). TRPV4 is characterized by both inward and outward rectification, voltage-dependent block by Ruthenium Red, a moderate selectivity for divalent versus monovalent cations, and an Eisenman IV permeability sequence. We identify two(More)
Combined patch-clamp and Fura-2 measurements were performed on chinese hamster ovary (CHO) cells co-expressing two channel proteins involved in skeletal muscle excitation-contraction (E-C) coupling, the ryanodine receptor (RyR)-Ca2+ release channel (in the membrane of internal Ca2+ stores) and the dihydropyridine receptor (DHPR)-Ca2+ channel (in the plasma(More)
Microfluorimetry and patch-clamp experiments were performed on TRPV6-expressing HEK cells to determine whether this Ca(2+)-sensing Ca(2+) channel is constitutively active. Intact cells loaded with fura-2 had an elevated intracellular free Ca(2+) concentration ([Ca(2+)](i)), which decreased to the same level such as in non-transfected cells if external(More)
Whole-cell patch-clamp experiments and optical measurements with the Ca2+ fluorescent dye fura-2 were performed to examine histamine induced cytosolic Ca2+ changes in bovine adrenal chromaffin cells. The purpose of this study was to find out whether the sustained plateau phase, which followed the rapid transient increase, was due to Ca2+ influx. The(More)
Whole-cell patch-clamp recordings were made to examine the effects of the Ca2+ chelators EGTA and BAPTA on the biophysical properties of voltage-operated Ca2+ currents in bovine adrenal chromaffin cells. Ca2+ currents in the presence of either EGTA or BAPTA over a concentration range of 0.1-60 mM were recorded under otherwise identical conditions. Analysis(More)
The physiological role and activation mechanism for most proteins of the transient receptor potential (TRP) family are unknown. This is also the case for the highly Ca(2+) selective transient receptor potential vanilloid type 6 (TRPV6) channel. Patch clamp experiments were performed on transiently transfected human embryonic kidney (HEK) cells to address(More)
The histamine-induced biphasic increase of the intracellular free [Ca2+] ([Ca2+]i) was studied in bovine adrenal chromaffin cells using fura-2 microfluorimetry and the whole-cell patch-clamp technique. Both the rapid, transient Ca2+ rise and the sustained plateau component of elevated [Ca2+]i were independent of extracellular Ca2+. Incubation with the(More)
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