The lack of selective gap junctional uncoupling agents has hampered evaluation of the contribution of intercellular communication to pharmacomechanical coupling and vascular contractility. Thus we further explored the utility and selectivity of heptanol as a gap junctional uncoupling agent in isolated rat aortic rings. Fifty-two aortic rings were obtained from 15 rats and were precontracted to ~75% of maximum with phenylephrine (PE). When contraction achieved steady state (~5 min), a single concentration of heptanol (200 µM) was added to each aortic ring at 1- to 3-min intervals for up to 42 min post-PE addition. At early time points (5-10 min after PE), heptanol elicited an ~50% loss of tension (i.e., relaxation). At subsequent time points post-PE, a gradual and time-dependent decrease in the magnitude of the heptanol-induced relaxation was observed until, after ~40 min, addition of heptanol was associated with little, if any, detectable relaxation. Linear regression analysis of the magnitude of the heptanol-induced relaxation vs. the square root of the elapsed time interval (from addition of PE) revealed a highly significant negative correlation (P < 0.001, R = 0.81). Studies conducted on KCl-precontracted aortic rings revealed no detectable heptanol-induced relaxation after development of the steady-state KCl-induced contraction. These data extend our previous observations to further document the potential utility of heptanol as a "relatively selective" uncoupling agent.

vascular smooth muscle; rat aortic rings; phenylephrine; pharmacomechanical coupling

This article has been cited by other articles:

				Y. Takeda, S. M. Ward, K. M. Sanders, and S. D. Koh Effects of the gap junction blocker glycyrrhetinic acid on gastrointestinal smooth muscle cells Am J Physiol Gastrointest Liver Physiol, April 1, 2005; 288(4): G832 - G841. [Abstract] [Full Text] [PDF]

				S. Earley, T. C. Resta, and B. R. Walker Disruption of smooth muscle gap junctions attenuates myogenic vasoconstriction of mesenteric resistance arteries Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2677 - H2686. [Abstract] [Full Text] [PDF]

				I. C. Solomon, K. H. Chon, and M. N. Rodriguez Blockade of Brain Stem Gap Junctions Increases Phrenic Burst Frequency and Reduces Phrenic Burst Synchronization in Adult Rat J Neurophysiol, January 1, 2003; 89(1): 135 - 149. [Abstract] [Full Text] [PDF]

				G. Lagaud, V. Karicheti, Harm. J. Knot, G. J. Christ, and I. Laher Inhibitors of gap junctions attenuate myogenic tone in cerebral arteries Am J Physiol Heart Circ Physiol, December 1, 2002; 283(6): H2177 - H2186. [Abstract] [Full Text] [PDF]

				W. M. Kuebler, X. Ying, and J. Bhattacharya Mechanotransduction in the Lung: Pressure-induced endothelial Ca2+ oscillations in lung capillaries Am J Physiol Lung Cell Mol Physiol, May 1, 2002; 282(5): L917 - L923. [Abstract] [Full Text] [PDF]

				H.-Z. Wang, N. Day, M. Valcic, K. Hsieh, S. Serels, P. R. Brink, and G. J. Christ Intercellular communication in cultured human vascular smooth muscle cells Am J Physiol Cell Physiol, July 1, 2001; 281(1): C75 - C88. [Abstract] [Full Text] [PDF]

				H. Sauer, J. Hescheler, and M. Wartenberg Mechanical strain-induced Ca2+ waves are propagated via ATP release and purinergic receptor activation Am J Physiol Cell Physiol, August 1, 2000; 279(2): C295 - C307. [Abstract] [Full Text] [PDF]

				Y. Ashino, X. Ying, L. G. Dobbs, and J. Bhattacharya [Ca2+]i oscillations regulate type II cell exocytosis in the pulmonary alveolus Am J Physiol Lung Cell Mol Physiol, July 1, 2000; 279(1): L5 - L13. [Abstract] [Full Text] [PDF]

				W. Schubert, P. G. Frank, B. Razani, D. S. Park, C.-W. Chow, and M. P. Lisanti Caveolae-deficient Endothelial Cells Show Defects in the Uptake and Transport of Albumin in Vivo J. Biol. Chem., December 21, 2001; 276(52): 48619 - 48622. [Abstract] [Full Text] [PDF]