The fluorescence spectra of Quin 2, (2-[(2-bis-[carboxymethyl] amino-5-methylphenoxy) methyl]-6-methoxy-8-bis [carboxymethyl] aminoquiniline), a Ca2+ probe, were investigated upon incubation with Ca2+ or La3+. The res...The fluorescence spectra of Quin 2, (2-[(2-bis-[carboxymethyl] amino-5-methylphenoxy) methyl]-6-methoxy-8-bis [carboxymethyl] aminoquiniline), a Ca2+ probe, were investigated upon incubation with Ca2+ or La3+. The results showed that binding of La3+ to Quin 2 resulted in different fluorescent spectrum from that of Ca2+. Based on this observation, a fluorescent method was developed for simultaneously determination of the dissociation rates of Ca2+ and La3+ from a Ca-La- calmodulin complex (Ca2La2CaM).展开更多
The intracellular free calcium concentration plays a key role as the second messenger in the regulation of cellular reaction.The changes of cytoplasmic free calcium concentration([Ca^(2+)]_i) in human platelets loaded...The intracellular free calcium concentration plays a key role as the second messenger in the regulation of cellular reaction.The changes of cytoplasmic free calcium concentration([Ca^(2+)]_i) in human platelets loaded with the fluorescent calcium indicator quin-2 were measured in this study. The result showed that thrombin(0.3 U/ml)raised the[Ca^(2+)]_i of platelets four to five times in the presence of 1 mmol/L external calcium.but there was a much smaller increase in[Ca^(2+)]_i in the absence of external calcium.It seems that thrombin increased[Ca^(2+)]_i partly by release of internal Ca^(2+),but mainly by stimulating influx.J-894 markedly inhibited the rise of[Ca^(2+)]_i in platelets induced by thrombin in a dose dependent manner through decreasing both calcium influx and calcium release.This suggests that J-894 may be a calcium channel blocker.展开更多
文摘The fluorescence spectra of Quin 2, (2-[(2-bis-[carboxymethyl] amino-5-methylphenoxy) methyl]-6-methoxy-8-bis [carboxymethyl] aminoquiniline), a Ca2+ probe, were investigated upon incubation with Ca2+ or La3+. The results showed that binding of La3+ to Quin 2 resulted in different fluorescent spectrum from that of Ca2+. Based on this observation, a fluorescent method was developed for simultaneously determination of the dissociation rates of Ca2+ and La3+ from a Ca-La- calmodulin complex (Ca2La2CaM).
文摘The intracellular free calcium concentration plays a key role as the second messenger in the regulation of cellular reaction.The changes of cytoplasmic free calcium concentration([Ca^(2+)]_i) in human platelets loaded with the fluorescent calcium indicator quin-2 were measured in this study. The result showed that thrombin(0.3 U/ml)raised the[Ca^(2+)]_i of platelets four to five times in the presence of 1 mmol/L external calcium.but there was a much smaller increase in[Ca^(2+)]_i in the absence of external calcium.It seems that thrombin increased[Ca^(2+)]_i partly by release of internal Ca^(2+),but mainly by stimulating influx.J-894 markedly inhibited the rise of[Ca^(2+)]_i in platelets induced by thrombin in a dose dependent manner through decreasing both calcium influx and calcium release.This suggests that J-894 may be a calcium channel blocker.
