Figure 1.
S1P receptor-mediated signalling in the heart. Activation of the S1P1 receptor induces negative inotropy through effects of Gαi to decrease cAMP concentration and effects of Gβγ on ion channels. The S1P2 receptor is the primary receptor for mediating Rho activation and this receptor mediated pathway may participate in cardioprotection. The S1P3 receptor is the primary receptor coupling to PLC and the activation of this receptor also results in bradycardia. While the S1P2 and S1P3 receptors appear to collaborate in providing cardioprotection from ischaemia reperfusion injury in vivo, the S1P1 receptor has been suggested to be cardioprotective in the isolated cardiomyocytes.