TY - JOUR
T1 - Endothelin-1 activates a Ca2+-permeable cation channel with TRPC3 and TRPC7 properties in rabbit coronary artery myocytes
AU - Peppiatt-Wildman, C. M.
AU - Albert, A. P.
AU - Saleh, S. N.
AU - Large, W. A.
PY - 2007/5/1
Y1 - 2007/5/1
N2 - In the present work we used patch pipette techniques to study the properties of a novel Ca2+-permeable cation channel activated by the potent coronary vasoconstrictor endothelin-1 (ET-1) in freshly dispersed rabbit coronary artery myocytes. With cell-attached recording bath application of 10 n m ET-1 evoked cation channel currents (Icat) with subconductance states of about 18, 34 and 51 and 68 pS, and a reversal potential of 0 mV. ET-1 evoked channel activity when extracellular Ca2+ was the charge carrier, illustrating significant Ca2+ permeability. ET-1-induced responses were inhibited by the ETA receptor antagonist BQ123 and the phospholipase C (PLC) inhibitor U73122. The diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) also stimulated Icat, but the protein kinase C (PKC) inhibitor chelerythrine did not inhibit either the OAG- or ET-1-induced Icat. Inositol 1,4,5-trisphosphate (IP3) did not activate Icat, but greatly potentiated the response to OAG and this effect was blocked by heparin. Bath application of anti-TRPC3 and anti-TRPC7 antibodies to inside-out patches markedly inhibited ET-1-evoked Icat, but antibodies to TRPC1, C4, C5 and C6 had no effect. Immunocytochemical studies demonstrated preferential TRPC7 expression in the plasmalemma, whereas TRPC3 was distributed throughout the myocyte, and moreover co-localization of TRPC3 and TRPC7 signals was observed at, or close to, the plasma membrane. Flufenamic acid, Gd3+, La3+ and extracellular Ca2+ inhibited Icat with IC50 values of 2.45 μM, 3.8 μ M, 7.36 μ M and 22 μ M, respectively. These results suggest that in rabbit coronary artery myocytes ET-1 evokes a Ca2+-permeable non-selective cation channel with properties similar to TRPC3 and TRPC7, and indicates that these proteins may be important components of this conductance.
AB - In the present work we used patch pipette techniques to study the properties of a novel Ca2+-permeable cation channel activated by the potent coronary vasoconstrictor endothelin-1 (ET-1) in freshly dispersed rabbit coronary artery myocytes. With cell-attached recording bath application of 10 n m ET-1 evoked cation channel currents (Icat) with subconductance states of about 18, 34 and 51 and 68 pS, and a reversal potential of 0 mV. ET-1 evoked channel activity when extracellular Ca2+ was the charge carrier, illustrating significant Ca2+ permeability. ET-1-induced responses were inhibited by the ETA receptor antagonist BQ123 and the phospholipase C (PLC) inhibitor U73122. The diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) also stimulated Icat, but the protein kinase C (PKC) inhibitor chelerythrine did not inhibit either the OAG- or ET-1-induced Icat. Inositol 1,4,5-trisphosphate (IP3) did not activate Icat, but greatly potentiated the response to OAG and this effect was blocked by heparin. Bath application of anti-TRPC3 and anti-TRPC7 antibodies to inside-out patches markedly inhibited ET-1-evoked Icat, but antibodies to TRPC1, C4, C5 and C6 had no effect. Immunocytochemical studies demonstrated preferential TRPC7 expression in the plasmalemma, whereas TRPC3 was distributed throughout the myocyte, and moreover co-localization of TRPC3 and TRPC7 signals was observed at, or close to, the plasma membrane. Flufenamic acid, Gd3+, La3+ and extracellular Ca2+ inhibited Icat with IC50 values of 2.45 μM, 3.8 μ M, 7.36 μ M and 22 μ M, respectively. These results suggest that in rabbit coronary artery myocytes ET-1 evokes a Ca2+-permeable non-selective cation channel with properties similar to TRPC3 and TRPC7, and indicates that these proteins may be important components of this conductance.
UR - http://www.scopus.com/inward/record.url?scp=34249857755&partnerID=8YFLogxK
U2 - 10.1113/jphysiol.2006.126656
DO - 10.1113/jphysiol.2006.126656
M3 - Article
C2 - 17303636
AN - SCOPUS:34249857755
SN - 0022-3751
VL - 580
SP - 755
EP - 764
JO - Journal of Physiology
JF - Journal of Physiology
IS - 3
ER -