Pharmacological profile of store-operated Ca(2+) entry in intrapulmonary artery smooth muscle cells.
Store-operated Ca(2+) entry (SOCE) plays an important role in the contraction and proliferation of pulmonary artery smooth muscle cells (PASMCs). The aim of this study was to characterise the pharmacological properties of the SOCE pathway in freshly isolated PASMCs from rat lung and to determine whether this Ca(2+) entry pathway is sensitive to nitric oxide donor drugs. Following depletion of Ca(2+) from the sarcoplasmic reticulum, by treating cells with thapsigargin, re-addition of Ca(2+) produced an increase in cytosolic fluo-4 fluorescence that was sustained for the period that extracellular Ca(2+) was present. Thapsigargin also increased the rate of quench of fura-2 fluorescence, confirming that SOCE was activated. The SOCE pathway was not affected by nifedipine or verapamil; however, it was inhibited by the divalent cations Ni(2+) (10 microM) and Cd(2+) (10 microM) by 47+/-5% and 49+/-5% respectively. SOCE was also inhibited 42+/-5% by 2-aminoethoxydiphenyl borate (2-APB; 75 microM) and 58+/-4% by Gd(3+) (10 microM), although La(3+) (100 microM) had little effect. None of the NO donors examined, including sodium nitroprusside, glyceryl trinitrate, and 2-(N,N-diethylamino)-diazenolate-2-oxide had any effect on SOCE. Thus, the pulmonary vasorelaxation produced by NO does not involve direct inhibition of SOCE in PASMCs. Western blot and immunocytochemistry using antibodies directed against specific TRPC subunits detected the presence of TRPC1, 3, and 6 in pulmonary artery and the pharmacological profile of SOCE in PASMCs favours a role for TRPC1 in mediating the underlying channels that are activated by store depletion.
McElroy
Stuart P
SP
Division of Physiology and Pharmacology, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0NR, United Kingdom.
Gurney
Alison M
AM
Drummond
Robert M
RM
D000818:Animals; D015153:Blotting, Western; D001896:Boron Compounds / Q000494:pharmacology; D002104:Cadmium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D004048:Diethylamines / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005682:Gadolinium / Q000378:metabolism; D007150:Immunohistochemistry; D007211:Indoles / Q000494:pharmacology; D007811:Lanthanum / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009532:Nickel / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D050052:TRPC Cation Channels / Q000187:drug effects / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
D001896:Boron Compounds; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004048:Diethylamines; D004791:Enzyme Inhibitors; D007211:Indoles; D020030:Nitric Oxide Donors; D050052:TRPC Cation Channels; D014665:Vasodilator Agents; C096351:transient receptor potential cation channel, subfamily C, member 1; D002104:Cadmium; D009599:Nitroprusside; D009569:Nitric Oxide; D019284:Thapsigargin; D007811:Lanthanum; D009532:Nickel; C087229:diethylamine dinitric oxide adduct; D005682:Gadolinium; D014700:Verapamil; C109986:2-aminoethoxydiphenyl borate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D005996:Nitroglycerin; D009543:Nifedipine; C000543:cyclopiazonic acid