The Role of L- and T-Type Calcium Channels in Local and Remote Calcium Responses in Rat Mesenteric Terminal Arterioles

TY - JOUR

T1 - The Role of L- and T-Type Calcium Channels in Local and Remote Calcium Responses in Rat Mesenteric Terminal Arterioles

AU - Braunstein, Thomas Hartig

AU - Inoue, Ryuji

AU - Cribbs, Leanne

AU - Oike, Masahiro

AU - Ito, Yushi

AU - von Holstein-Rathlou, Niels-Henrik

AU - Jensen, Lars Jørn

N1 - Copyright © 2008 S. Karger AG, Basel.

PY - 2009

Y1 - 2009

N2 - Background/Aims: The roles of intercellular communication and T-type versus L-type voltage-dependent Ca(2+) channels (VDCCs) in conducted vasoconstriction to local KCl-induced depolarization were investigated in mesenteric arterioles. Methods: Ratiometric Ca(2+) imaging (R) using Fura-PE3 with micro-ejection of depolarizing KCl solution and VDCC blockers, and immunohistochemical and RT-PCR techniques were applied to isolated rat mesenteric terminal arterioles (n = 71 from 47 rats; intraluminal diameter: 24 +/- 1 mum; length: 550-700 mum). Results: Local application of KCl (at 0 mum) led to local (DeltaR = 0.54) and remote (DeltaR = 0.17 at 500 mum) increases in intracellular Ca(2+). Remote Ca(2+) responses were inhibited by the gap junction uncouplers carbenoxolone and palmitoleic acid. Ca(V)1.2, Ca(V)3.1 and Ca(V)3.2 channels were immunolocalized in vascular smooth muscle cells and Ca(V)3.2 in adjacent endothelial cells. Local and remote Ca(2+) responses were inhibited by bath application of L- and T-type blockers [nifedipine, NNC 55-0396 and R(-)-efonidipine]. Remote Ca(2+) responses (500 mum) were not affected by abolishing Ca(2+) entry at an intermediate position on the arterioles (at 200-300 mum) using micro-application of VDCC blockers. Conclusion: Both L- and T-type channels mediate Ca(2+) entry during conducted vasoconstriction to local KCl in mesenteric arterioles. However, these channels do not participate in the conduction process per se.

AB - Background/Aims: The roles of intercellular communication and T-type versus L-type voltage-dependent Ca(2+) channels (VDCCs) in conducted vasoconstriction to local KCl-induced depolarization were investigated in mesenteric arterioles. Methods: Ratiometric Ca(2+) imaging (R) using Fura-PE3 with micro-ejection of depolarizing KCl solution and VDCC blockers, and immunohistochemical and RT-PCR techniques were applied to isolated rat mesenteric terminal arterioles (n = 71 from 47 rats; intraluminal diameter: 24 +/- 1 mum; length: 550-700 mum). Results: Local application of KCl (at 0 mum) led to local (DeltaR = 0.54) and remote (DeltaR = 0.17 at 500 mum) increases in intracellular Ca(2+). Remote Ca(2+) responses were inhibited by the gap junction uncouplers carbenoxolone and palmitoleic acid. Ca(V)1.2, Ca(V)3.1 and Ca(V)3.2 channels were immunolocalized in vascular smooth muscle cells and Ca(V)3.2 in adjacent endothelial cells. Local and remote Ca(2+) responses were inhibited by bath application of L- and T-type blockers [nifedipine, NNC 55-0396 and R(-)-efonidipine]. Remote Ca(2+) responses (500 mum) were not affected by abolishing Ca(2+) entry at an intermediate position on the arterioles (at 200-300 mum) using micro-application of VDCC blockers. Conclusion: Both L- and T-type channels mediate Ca(2+) entry during conducted vasoconstriction to local KCl in mesenteric arterioles. However, these channels do not participate in the conduction process per se.

U2 - 10.1159/000151767

DO - 10.1159/000151767

M3 - Journal article

C2 - 18765948

SN - 1018-1172

VL - 46

SP - 138

EP - 151

JO - Journal of Vascular Research

JF - Journal of Vascular Research

IS - 2

ER -