Vladimir Matchkov

Na+/K+-pump modulates intercellular communication viainteraction with other membrane transporters in vascularsmooth muscle cells.

Research output: Contribution to conferenceConference abstract for conferenceResearch

  • Danish Biomembrane Research Centre

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.

Original languageEnglish
Publication year2007
Number of pages1
Publication statusPublished - 2007
EventExperimental Biology 2007 - Washington, United States
Duration: 27 Apr 20072 May 2007

Conference

ConferenceExperimental Biology 2007
CountryUnited States
CityWashington
Period27/04/200702/05/2007

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