Research output: Contribution to conference › Conference abstract for conference › Research
Na+/K+-pump modulates intercellular communication viainteraction with other membrane transporters in vascularsmooth muscle cells. / Matchkov, Vladimir; Hansen, Anne Kirstine; Nilsson, Holger et al.
2007. Abstract from Experimental Biology 2007, Washington, United States.Research output: Contribution to conference › Conference abstract for conference › Research
}
TY - ABST
T1 - Na+/K+-pump modulates intercellular communication viainteraction with other membrane transporters in vascularsmooth muscle cells.
AU - Matchkov, Vladimir
AU - Hansen, Anne Kirstine
AU - Nilsson, Holger
AU - Aalkjær, Christian
PY - 2007
Y1 - 2007
N2 - Ouabain, an inhibitor of the Na+/K+-pump, has previously been shown to disturb intercellular communication. Here we test the hypothesis that the communication between vascular smooth muscle cells (SMCs) is regulated through an interaction between the Na+/K+-pump and the Na+/Ca2+-exchanger in restricted spaces near the plasma membrane.The intracellular Ca2+ concentration ([Ca2+]i) in individual SMCs was imaged simultaneously with isometric force in rat mesenteric small arteries. Paired cultured rat aortic smooth muscle cells (A7r5) were used as a model for electrical coupling of SMC by measuring membrane capacitance (Cm).SMCs were uncoupled (evaluated by inhibition of vasomotion and desynchronization of [Ca2+]i transients in vascular wall, or by reduction of Cm measured in electrically coupled A7r5 cells) when the Na+/K+-pump was inhibited either by a low concentration of ouabain (1-10 µM) or by ATP depletion. Reduction of Na+/K+-pump activity by removal of extracellular K+ also uncoupled cells, but only after inhibition of KATP channels. Inhibition of the Na+/Ca2+-exchange activity by SEA0400 or by lowering the extracellular Na+ concentration also uncoupled the cells. Depletion of [Na+]i and clamping low [Ca2+]i prevented the uncoupling.The experiments suggest that the Na+/K+-pump may affect gap junction conductivity via localized changes in [Ca2+]i through modulation of Na+/Ca2+-exchanger activity.
AB - Ouabain, an inhibitor of the Na+/K+-pump, has previously been shown to disturb intercellular communication. Here we test the hypothesis that the communication between vascular smooth muscle cells (SMCs) is regulated through an interaction between the Na+/K+-pump and the Na+/Ca2+-exchanger in restricted spaces near the plasma membrane.The intracellular Ca2+ concentration ([Ca2+]i) in individual SMCs was imaged simultaneously with isometric force in rat mesenteric small arteries. Paired cultured rat aortic smooth muscle cells (A7r5) were used as a model for electrical coupling of SMC by measuring membrane capacitance (Cm).SMCs were uncoupled (evaluated by inhibition of vasomotion and desynchronization of [Ca2+]i transients in vascular wall, or by reduction of Cm measured in electrically coupled A7r5 cells) when the Na+/K+-pump was inhibited either by a low concentration of ouabain (1-10 µM) or by ATP depletion. Reduction of Na+/K+-pump activity by removal of extracellular K+ also uncoupled cells, but only after inhibition of KATP channels. Inhibition of the Na+/Ca2+-exchange activity by SEA0400 or by lowering the extracellular Na+ concentration also uncoupled the cells. Depletion of [Na+]i and clamping low [Ca2+]i prevented the uncoupling.The experiments suggest that the Na+/K+-pump may affect gap junction conductivity via localized changes in [Ca2+]i through modulation of Na+/Ca2+-exchanger activity.
M3 - Conference abstract for conference
Y2 - 27 April 2007 through 2 May 2007
ER -