It is a specific inhibitor of Ca²⁺-ATPase in the intracellular Ca²⁺ storage sites.

CPA is a highly selective inhibitor of Ca²⁺ - ATPase in skeletal muscle sarcoplasmic reticulum. It
stimulates release of Ca²⁺ from intracellular stores by increasing plasma membrane Ca²⁺ permeability without increasing intracellular inositol (1,4,5)-triphosphate levels. inhibits the Ca²⁺ uptake: by sarcoplasmic vesicles prepared from skeletal muscle, by intracellular stores sites caffeine-sensitive in guinea-pig smooth muscle cells (3μM); IC50 around 0.6 μM in skinned smooth muscle fibres of the longitudinal layer of the guinea-pig ileum.

It causes selective and reversible strong suppression of Ca²⁺-dependent K⁺ current in guinea-pig ileal and urinary bladder smooth muscle cells. It is effective in intact cells and can be washed out.
Its mechanism of action may be the following: decreases Ca²⁺ uptake by the inhibition of Ca²⁺ -pump in the sarcoplasmic and endoplasmic reticulum, decreases the subsequent Ca²⁺ release from these storage sites and, thereby, reduces the Ca²⁺ dependent K⁺ current.

Stable in dry state, store at +4°C, avoiding humidity.

For research use only — not intended for food, diagnostic or therapeutic use
Toxic