Characteristics of Ca2+-exocytosis coupling in isolated mouse pancreatic β cells

Aim: To characterize Ca2+-stimulated exocytosis in isolated mouse pancreatic beta cells. Methods: An improved method was described for isolation of mouse pancreatic beta cells by collagenase P. The Ca2+ channel current and the membrane capacitance were examined by using the whole-cell patch clamp recording technique. Results: Using depolarization and flash photolysis of caged Ca2+ to induce Ca2+-dependent exocytosis in beta cell from KM mouse, we have explored the characteristics of the Ca2+ channel current and the relationship between Ca2+ signals and exocytosis. The averaged peak Ca2+ current measured at +20 mV was -60 +/- 6 pA (n= 13). Conclusion: We characterized three kinetically different pools of vesicles in mouse pancreatic beta cells, namely an immediately releasable pool, a readily releasable pool, and a reserve pool.