doi: 10.1161/01.RES.0000265133.89488.9b
© 2007 American Heart Association, Inc.
Editorials |
Closing the Gap at Hot Spots
From the Institut für Physiologie, Universität Lübeck, Germany.
Correspondence to Dr Cor de Wit, Institut für Physiologie, Universität Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. E-mail dewit@uni-luebeck.de
See related article, pages 1026–1035
Key Words: connexin • Ca2+ microdomains • Na+/K+-pump • Na+-Ca2+-exchange
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
Coordination of cellular behavior is indispensable for vascular function. Because of the structural design of the vascular tree only an orchestrated diameter change along the vessel length increases conductance significantly and ensures optimal tissue perfusion. Mechanisms that suffice these needs include locally generated signals at upstream sites which reflect downstream requirements (flow-induced dilation)1 and longitudinal signal transmission through communication channels residing in the vessel wall itself which enable the synchronisation of cellular behavior. This latter is achieved by homocellular gap junctions which are composed of connexins that connect adjacent cells by intercellular low-resistance channels establishing a functional syncitium.2 Electrical communication through these channels is experimentally studied by locally initiated vasomotor responses which conduct along the vessel wall and promote synchronized dilations or constrictions of arteriolar segments reflecting the coordination of cellular behavior.3 Longitudinal communication through gap junctions is also required for the synchronisation of intracellular Ca2+ ([Ca2+]i) changes in smooth muscle and subsequent vasomotion, ie, rhythmic oscillations of vascular diameter. Although the physiological significance of vasomotion is still to be clearly defined it depends critically on Ca2+ release from intracellular stores which occurs in an oscillating fashion and the synchronization of [Ca2+]i transients through gap junctional communication.4,5 In addition, endothelial and smooth muscle cells are coupled heterocellularly (myoendothelial junctions) allowing the direct spread of current from the endothelium to the smooth muscle6 or other signaling molecules.7
The importance of gap junctional communication in vascular function contrasts with the poor knowledge of its regulation in vessels which is
Related Article:
Circ. Res. 2007 100: 1026-1035.