|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1993 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1992 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1991 : ¥700,000 (Direct Cost : ¥700,000)
We applied a patch-clamp technique to highly purified human basophils and examined the effect of intracellular Ca concentration ([Ca^<2+>]_i) on granule release by morphological and electrophysiological measurement. In addition, we examined the effect of guanosine 5'-_0-(3-thiortriphosphate) (GTP-gamma-S) and a specific protein kinase C inhibitor, calphostin C, on intracellular Ca-induced granule release. We obtained the following results : First, intracellular application of Ca, 1-10muM, caused granule fusion, which was confirmed by the definite correlation between morphological and electrophysiological changes. The addition of GTP-gamma-S,100muM, promoted granule release by 4.4 times at 2muM Ca in association with marked morphological changes. In addition, GTP-gamma-S caused significant granule membrane fusion even at 0.1muM Ca. Calphostin C, 200nM, inhibited intracellular Ca-and intracellular Ca+GTP-gamma-S-induced granule release by 69% and 50%, respectively. These results indicate that granule membrane fusion is induced by an increase in intracellular Ca alone at relatively high concentrations in the human basophil. In addition, GTP binding proteins and protein kinase C would modulate the Ca-induced granule release.