This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 101/12/1292    most recent CIRCRESAHA.107.163279v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wölfle, S. E. Articles by de Wit, C. Search for Related Content PubMed PubMed Citation Articles by Wölfle, S. E. Articles by de Wit, C. Related Collections Genetically altered mice Other Vascular biology Related Article

(Circulation Research. 2007;101:1292.)
© 2007 American Heart Association, Inc.

Integrative Physiology

Connexin45 Cannot Replace the Function of Connexin40 in Conducting Endothelium-Dependent Dilations Along Arterioles

Stephanie E. Wölfle^*, Volker J. Schmidt^*, Bernd Hoepfl, Andreas Gebert, Sébastien Alcoléa, Daniel Gros, Cor de Wit

From the Institut für Physiologie (S.E.W., V.J.S., B.H., C.d.W.) and Institut für Anatomie (A.G.) der Universität zu Lübeck, Germany; and Laboratoire de Génétique et Physiologie du Développement (S.A., D.G.), Université de la Méditerranée, Marseille, France.

Correspondence to Cor de Wit, MD, PhD, Physiologisches Institut, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany. E-mail dewit{at}uni-luebeck.de

Intercellular communication through gap junctions coordinates vascular tone by the conduction of vasomotor responses along the vessel wall. Gap junctions in arterioles are composed of different connexins (Cxs) (Cx40, Cx37, Cx45, Cx43), but it is unknown whether Cxs are interchangeable. We used mice with a targeted replacement of Cx40 by Cx45 (Cx40KI45) to explore whether Cx45 can functionally replace Cx40 in arterioles. Arterioles were locally stimulated using acetylcholine, bradykinin, adenosine, and K⁺ in the cremaster of Cx40KI45, Cx40-deficient (Cx40ko), and wild-type mice, and diameter changes were assessed by intravital microscopy. Additionally, arterial pressure was measured by telemetry and Cx expression verified by immunofluorescence. Acetylcholine initiated a local dilation of a similar amplitude in all genotypes (50%), which was rapidly conducted to upstream sites (1200 µm distance) without attenuation in wild type. In marked contrast, the remote dilation was significantly reduced in Cx40ko (25±3%) and Cx40KI45 (24±2%). Likewise, dilations initiated by bradykinin application were conducted without attenuation up to 1200 µm in wild type but not in Cx40ko and Cx40KI45. Adenosine-induced dilations and K⁺-induced constrictions were conducted similarly with decaying amplitude in all genotypes. Arterial pressure was strongly elevated in Cx40ko (161±1 versus 116±2 mm Hg) but only moderately in Cx40KI45 (133±8 mm Hg). This demonstrates that Cx40 function is critical for the conduction of acetylcholine and bradykinin dilations and cannot be substituted by Cx45. Therefore, unique properties of Cx40 are required for endothelial signal conduction, whereas nonspecific restoration of communication maintains additional functions related to blood pressure control.

Key Words: conducted responses • gap junctional communication • connexin40 • connexin45 • microcirculation

Related Article:

Which Connexins Connect?

Tudor M. Griffith
Circ. Res. 2007 101: 1219-1221. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

				C. de Wit Different pathways with distinct properties conduct dilations in the microcirculation in vivo Cardiovasc Res, October 31, 2009; (2009) cvp340v2. [Abstract] [Full Text] [PDF]

				L. Kurtz, M. Gerl, W. Kriz, C. Wagner, and A. Kurtz Replacement of connexin 40 by connexin 45 causes ectopic localization of renin-producing cells in the kidney but maintains in vivo control of renin gene expression Am J Physiol Renal Physiol, August 1, 2009; 297(2): F403 - F409. [Abstract] [Full Text] [PDF]

				D. A. Goodenough and D. L. Paul Gap Junctions Cold Spring Harb Perspect Biol, July 1, 2009; 1(1): a002576 - a002576. [Abstract] [Full Text] [PDF]

				S. E. Wolfle, V. J. Schmidt, J. Hoyer, R. Kohler, and C. de Wit Prominent role of KCa3.1 in endothelium-derived hyperpolarizing factor-type dilations and conducted responses in the microcirculation in vivo Cardiovasc Res, June 1, 2009; 82(3): 476 - 483. [Abstract] [Full Text] [PDF]

				X. F. Figueroa and B. R. Duling Dissection of two Cx37-independent conducted vasodilator mechanisms by deletion of Cx40: electrotonic versus regenerative conduction Am J Physiol Heart Circ Physiol, November 1, 2008; 295(5): H2001 - H2007. [Abstract] [Full Text] [PDF]

				T. M. Griffith Which Connexins Connect? Circ. Res., December 7, 2007; 101(12): 1219 - 1221. [Full Text] [PDF]