Figure 8. Schematic diagram of mechanisms for the extracellular acidification inducing “Ca²⁺ transients” in cultured rat cardiac myocytes.

There are two components for Ca²⁺ elevation in response to elevated external protons, one is ASIC/TRPV1 channel and another is OGR1protein. On one side, ASICs and TRPV1 can be activated by acidosis solution and mediate extracellular Ca²⁺ entry. On the other side, OGR1 mediates mobilization of intracellular Ca²⁺ from SR via OGR1-PLC-IP3-IP3R signaling pathway.