AJP - Cell Physiology, Vol 260, Issue 5 C975-C981, Copyright © 1991 by American Physiological Society

ARTICLES

Characterization of gap junction channels in A7r5 vascular smooth muscle cells

L. K. Moore, E. C. Beyer and J. M. Burt
Department of Physiology, University of Arizona, Tucson 85724.

Recent evidence suggest that coordination of blood flow in the microcirculation involves cell-to-cell coupling via gap junctions. In this study, using A7r5 cells as a model of vascular smooth muscle, we have characterized the gap junctions in terms of the unitary conductances of the observed channels, the responses to second messengers, and subunit protein composition. The cells were typically well coupled several hours after plating, with junctional conductances on the order 20-40 nS. Channels with mean conductances of 36 and 89 pS were observed in low-conductance cell pairs and in cell pairs whose macroscopic conductance was reduced by exposure to halothane. Connexin43 was the only known gap junction sequence detected by Northern blots (low and high stringency), immunoblots, or immunohistochemical studies. Junctional conductance was reduced 15% by 8-bromoadenosine 3',5'-cyclic monophosphate; 8-bromoguanosine 3',5'-cyclic monophosphate had no effect. The results suggest that connexin43 can form stable channels of at least two distinct conductances and gap junctions with differing responses to second messengers.

This article has been cited by other articles:

				G. T. Cottrell, Y. Wu, and J. M. Burt Cx40 and Cx43 expression ratio influences heteromeric/ heterotypic gap junction channel properties Am J Physiol Cell Physiol, June 1, 2002; 282(6): C1469 - C1482. [Abstract] [Full Text] [PDF]

				G. T. Cottrell and J. M. Burt Heterotypic gap junction channel formation between heteromeric and homomeric Cx40 and Cx43 connexons Am J Physiol Cell Physiol, November 1, 2001; 281(5): C1559 - C1567. [Abstract] [Full Text] [PDF]

				J. M. Burt, A. M. Fletcher, T. D. Steele, Y. Wu, G. T. Cottrell, and D. T. Kurjiaka Alteration of Cx43:Cx40 expression ratio in A7r5 cells Am J Physiol Cell Physiol, March 1, 2001; 280(3): C500 - C508. [Abstract] [Full Text] [PDF]

				J.-A. Haefliger, P. Meda, A. Formenton, P. Wiesel, A. Zanchi, H. R. Brunner, P. Nicod, and D. Hayoz Aortic Connexin43 Is Decreased During Hypertension Induced by Inhibition of Nitric Oxide Synthase Arterioscler. Thromb. Vasc. Biol., July 1, 1999; 19(7): 1615 - 1622. [Abstract] [Full Text] [PDF]

				Y.-S. Ko, H.-I Yeh, M. Haw, E. Dupont, R. Kaba, G. Plenz, H. Robenek, and N. J. Severs Differential Expression of Connexin43 and Desmin Defines Two Subpopulations of Medial Smooth Muscle Cells in the Human Internal Mammary Artery Arterioscler. Thromb. Vasc. Biol., July 1, 1999; 19(7): 1669 - 1680. [Abstract] [Full Text] [PDF]

				X. Li and J. M. Simard Multiple Connexins Form Gap Junction Channels in Rat Basilar Artery Smooth Muscle Cells Circ. Res., June 11, 1999; 84(11): 1277 - 1284. [Abstract] [Full Text] [PDF]

				D. T. Kurjiaka, T. D. Steele, M. V. Olsen, and J. M. Burt Gap junction permeability is diminished in proliferating vascular smooth muscle cells Am J Physiol Cell Physiol, December 1, 1998; 275(6): C1674 - C1682. [Abstract] [Full Text] [PDF]

				J.-A. Haefliger, E. Castillo, G. Waeber, G. E. Bergonzelli, J.-F. Aubert, E. Sutter, P. Nicod, B. Waeber, and P. Meda Hypertension Increases Connexin43 in a Tissue-Specific Manner Circulation, February 18, 1997; 95(4): 1007 - 1014. [Abstract] [Full Text]

				S. W. Watts and R. C. Webb Vascular Gap Junctional Communication Is Increased in Mineralocorticoid-Salt Hypertension Hypertension, November 1, 1996; 28(5): 888 - 893. [Abstract] [Full Text]

				K. L. Byron Vasopressin Stimulates Ca2+ Spiking Activity in A7r5 Vascular Smooth Muscle Cells via Activation of Phospholipase A2 Circ. Res., May 1, 1996; 78(5): 813 - 820. [Abstract] [Full Text]