Calcium-Dependent and Independent Mechanisms of Contraction in Canine Lingual Artery to U-46619
The thromboxane A2/prostaglandin H2 (TXA2/PGH2) mimetic, U-46619, is a potent platelet aggregating agent and constrictor of vascular smooth muscle. Aggregation and contraction to U-46619, and other TXA2/PGH2 mimetics, such as U-44069 and carbocyclic TXA2, are associated with both an influx of extracellular Ca2+ and a release of Ca2+ from binding and sequestration sites within the platelet and arterial smooth muscle (Greenberg, 1981; Loutzenhiser and van Breemen, 1981; Dorn et al., 1987; Santoian et al., 1987). These mechanisms were shown by the ability of both calcium channel blocking agents and intracellular calcium antagonists, such as dantrolene sodium and TMB-8, to inhibit contraction of vascular smooth muscle to TXA2/PGH2 receptor mimetics and by the ability of these mimetics to increase 45Ca efflux without affecting 45Ca uptake (Ally et al., 1978; Greenberg, 1981; Loutzenhiser and Van Breemen, 1981; Angerio et al., 1982; Dorn et al., 1987; Santoian et al., 1987). The pool of Ca2+ utilized for the physiologic and pharmacologic actions of U-46619 appears to depend on the site and species from which the arteries and platelets are obtained (Greenberg, 1981; Loutzenhiser and Van Breemen, 1981; Angerio et al., 1982; Dorn et al, 1987; Santoian et al., 1987; Verheyen et al., 1989).
KeywordsMesenteric Artery Sustained Contraction Physiological Salt Solution Lingual Artery Dantrolene Sodium
Unable to display preview. Download preview PDF.
- Greenberg, S., Wang, Y., Xie, J., Diecke, F. P. J., Smartz, L., Rammazzatto, L., and Curro, F. A., 1991, Thromboxane released during trauma and inflammation may contribute to tongue and periodontium dysfu nction, J. Dental Res., in press.Google Scholar
- Mene, P., Dubyak, G. R., Abboud, H. E., Scarpa, A., and Dunn, M. J., 1988, Phospholipase C activation by prostaglandins and thromboxane A2 in cultured mesangial cells. Am. J. Physiol., 255: Fl059.Google Scholar
- Wang Y., Xie, J., Greenberg, S., Diecke, F.P.J., Smartz, L., Rammazzatto, L., and Curro, F.A., 1991, Evidence for Ca2+ and protein kinase C dependent and independent contraction of lingual artery, J. Pharmacol. Exp. Ther., in press.Google Scholar