Expression profiles of S1P receptor mRNAs in rat heart tissue. A: Expression of regionally distributed MLCA1 and MLC2V in the atria, SAN and ventricle tissues. B: Expression profile of S1P receptors mRNAs in sinoatrial node tissue, in atrial tissue and in ventricular tissue. Means ± SEM (n = 7) shown. *p < 0.05; One way ANOVA. LV, left ventricle; RA, right atrium; SAN, sinoatrial node; MLC1A, atrial myosin light chain gene; MLC2V, ventricular myosin light chain gene.