Na^+/Ca^(2+) Exchange-mediated La^(3+) Entry in Human Lymphocytes  

作　　者：Chun Ying WEI Pin YANG Hai Yan WANG 

机构地区：[1]Institute of Molecular Science,Shanxi University,Taiyuan 030006

出　　处：《Chinese Chemical Letters》2001年第9期815-816,共2页中国化学快报(英文版)

基　　金：The authors acknowledge the support of the National Natural Scicnce Foundation of China;Provincial Natural Science Foundation of Shanxi.

摘　　要：We determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+ exchanger (measured with fura-2). We first compared the sensitivity of fura-2 with La3+ and Ca2+, the result indicates that the sensitivity of fura-2 for La3+ is much greater than for Ca2+. La3+ forms a 1:1 La3+-fura-2 complex (apparent dissociation constant = 1.7x10(-12) mol/L, pH 7.05). Ouabain-pretreated cells, suspended in Na+-free medium, showed that La3+ can enter human lymphocytes via the Na-i(+)/Ca2+ (La3+)(o) exchanger and is found to be about 10(-12) mol/L in cells exposed to 0.4 mmol/L La3+. Otherwise, the higher concentration (0.1 mmol/L) blocks the Na-i(+)/Ca2+(La3+)(o) exchange-mediated influx of Ca2+, but the lower concentration (0.01 mmol/L) appears to increase Ca2+ entry.We determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+ exchanger (measured with fura-2). We first compared the sensitivity of fura-2 with La3+ and Ca2+, the result indicates that the sensitivity of fura-2 for La3+ is much greater than for Ca2+. La3+ forms a 1:1 La3+-fura-2 complex (apparent dissociation constant = 1.7x10(-12) mol/L, pH 7.05). Ouabain-pretreated cells, suspended in Na+-free medium, showed that La3+ can enter human lymphocytes via the Na-i(+)/Ca2+ (La3+)(o) exchanger and is found to be about 10(-12) mol/L in cells exposed to 0.4 mmol/L La3+. Otherwise, the higher concentration (0.1 mmol/L) blocks the Na-i(+)/Ca2+(La3+)(o) exchange-mediated influx of Ca2+, but the lower concentration (0.01 mmol/L) appears to increase Ca2+ entry.

关 键 词：Na+/Ca2+ exchanger LYMPHOCYTES La3+ OUABAIN fluorescence indicator 

分 类 号：R313[医药卫生—基础医学]