THE EFFECT OF 2-AMINOETHOXYDIPHENYL BORATE ON STORE-DEPENDENT Ca<sup>2+</sup> ENTRY IN PERITONEAL MACROPHAGES
Store-dependent Ca<sup>2+</sup>-entry is a universal mechanism of regulated Ca<sup>2+</sup> entry in eucariotic cells. To elucidate the pharmacological characteristics of store-dependent Ca<sup>2+</sup> entry in macrophages, the effect of 2-aminoethoxydiphenyl borate (2-APB) on store-dependent Ca<sup>2+</sup> entry, induced by endoplasmic Ca<sup>2+</sup>-ATPases inhibitors thapsigargin and cyclopiazonic acid as well as disulfide-containing immunomodulators glutoxim and molixan, was investigated in rat peritoneal macrophages. Using Fura-2AM microfluorimetry we have shown that in rat peritoneal macrophages, as well as in other cell types, 2-APB modulates store-dependent Ca<sup>2+</sup> entry in a dose-dependent manner. At concentration of 25 μM 2-APB potentiates Ca<sup>2+</sup> entry, while at concentrations of 50 and 100 μM it effectively inhibits store-dependent Ca<sup>2+</sup> entry in macrophages. The results additionally confirm that Ca<sup>2+</sup> entry induced by glutoxim or molixan occurs via store-dependent mechanism.