Provider: Ingenta Connect Database: Ingenta Connect Content: application/x-research-info-systems TY - ABST AU - Angermann, Jeff E. AU - Forrest, Abigail S. AU - Greenwood, Iain A. AU - Leblanc, Normand TI - Activation of Ca2+-activated Cl– channels by store-operated Ca2+ entry in arterial smooth muscle cells does not require reverse-mode Na+/Ca2+ exchange JO - Canadian Journal of Physiology and Pharmacology PY - 2012-07-04T00:00:00/// VL - 90 IS - 7 SP - 903 EP - 921 KW - cellules de muscle lisse vasculaire KW - entrée de Ca2+ induite par vidange du reticulum sarcoplasmique (SOCE) KW - échange sodium-calcium KW - canaux chloriques activés par le calcium KW - hypertension pulmonaire KW - store-operated calcium entry KW - sodium-calcium exchange KW - calcium-activated chloride channels KW - vascular smooth muscle cells KW - pulmonary hypertension N2 - The main purpose of this study was to characterize the stimulation of Ca2+-activated Cl (ClCa) by store-operated Ca2+ entry (SOCE) channels in rabbit pulmonary arterial smooth muscle cells (PASMCs) and determine if this process requires reverse-mode Na+/Ca2+ exchange (NCX). In whole-cell voltage clamped PASMCs incubated with 1 μmol/L nifedipine (Nif) to inhibit Ca2+ channels, 30 μmol/L cyclopiazonic acid (CPA), a SERCA pump inhibitor, activated a nonselective cation conductance permeable to Na+ (ISOC) during an initial 1–3 s step, ranging from–120 to +60 mV, and Ca2+-activated Cl current (ICl(Ca)) during a second step to +90 mV that increased with the level of the preceding hyperpolarizing step. Niflumic acid (100 μmol/L), a ClCa channel blocker, abolished ICl(Ca) but had no effect on ISOC, whereas the ISOC blocker SKF-96365 (50 μmol/L) suppressed both currents. Dual patch clamp and Fluo-4 fluorescence measurements revealed the appearance of CPA-induced Ca2+ transients of increasing magnitude with increasing hyperpolarizing steps, which correlated with ICl(Ca) amplitude. The absence of Ca2+ transients at positive potentials following a hyperpolarizing step combined with the observation that SOCE-stimulated ICl(Ca) was unaffected by the NCX blocker KB-R7943 (1 μmol/L) suggest that the SOCE/ClCa interaction does not require reverse-mode NCX in our conditions. UR - https://www.ingentaconnect.com/content/cndscipub/cjpp/2012/00000090/00000007/art00010 M3 - doi:10.1139/y2012-081 UR - https://doi.org/10.1139/y2012-081 ER -