Alterations by a thromboxane A2 analog (U46619) of calcium dynamics in isolated rat cardiomyocytes.
Hoffmann-P; Heinroth-Hoffmann-I; Toraason-M
J Pharmacol Exp Ther 1993; 264(1):336-344
The effects of thromboxane-A2 (TXA2) on calcium transients were studied in electrically stimulated cultured neonatal rat cardiomyocytes. Myocytes were isolated from cardiac ventricular cells from 2 to 4 day old Sprague-Dawley-rats, and cultured. Administration of the TXA2 analog U46619 increased basal and peak calcium concentrations as well as width of electrically induced calcium transients in a concentration dependent manner during a 1 hour exposure. Exposure to 10 micromolar U46619 caused irregular calcium transients and a marked increase in cytosolic free calcium concentration. The authors conclude that they observed changes in calcium dynamics by the TXA2 analog U46619 in electrically stimulated single neonatal rat ventricular myocytes by using spectrophotometric analysis of fura-2 fluorescence. The actions of U46619 are receptor mediated and result in an increase in sarcoplasmic reticulum calcium which could be responsible for an enhanced calcium release during excitation contraction coupling. The authors suggest that the calcium loading of the myocytes is involved in the proischemic and arrhythmogenic actions of TXA2 in- situ.
NIOSH-Author; Cell-cultures; Myocardial-disorders; Cardiovascular-system-disorders; Laboratory-animals; In-vitro-studies; Mammalian-cells; Cardiovascular-function
Journal of Pharmacology and Experimental Therapeutics