1,2-双（2-氨基苯氧基）乙烷-N,N,N',N'-四乙酸-乙酰甲酯（BAPTA-AM）可阻断培养的牛嗜铬细胞中的电压门控性钾电流和钙激活钾电流。

BAPTA-AM blocks both voltage-gated and Ca2+-activated K+ currents in cultured bovine chromaffin cells.

作者信息

Urbano F J, Buño W

机构信息

Laboratorio de Fisiología y Biología Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.

出版信息

Neuroreport. 1998 Oct 26;9(15):3403-7. doi: 10.1097/00001756-199810260-00013.

DOI:10.1097/00001756-199810260-00013

PMID:9855289

Abstract

The effects of the membrane permeant Ca2+ chelator BAPTA-AM on voltage-gated Na+, Ca2+, K+ (I(Na), I(Ca) I(K), respectively) and Ca2+-activated K+ (I(KCa)) currents in cultured bovine chromaffin cells were investigated using the whole-cell patch-clamp technique. Superfusion with BAPTA-AM (50 microM) induced a rapid (< 60 s) and reversible block of both I(KCa) and I(K) (approximately 50%), without affecting either I(Ca) or I(Na). Preincubation with BAPTA-AM (50 microM, 30 min) or cell loading with the nonpermeable active form of BAPTA (10 mM in the pipette solution) permanently blocked I(KCa). BAPTA-AM superfusion (50 microM) also blocked I(K) (approximately 53%) after BAPTA-loading or BAPTA-AM preincubation. In conclusion, we show a fast and reversible block of I(KCa) and I(K) by BAPTA-AM, acting directly on K+ channels before it operates as a Ca2+ chelator, in cultured bovine chromaffin cells.

摘要

采用全细胞膜片钳技术，研究了膜通透性Ca2+螯合剂BAPTA-AM对培养的牛嗜铬细胞中电压门控的Na+、Ca2+、K+（分别为I(Na)、I(Ca)、I(K)）电流以及Ca2+激活的K+（I(KCa)）电流的影响。用BAPTA-AM（50微摩尔）进行灌流可快速（<60秒）且可逆地阻断I(KCa)和I(K)（约50%），而不影响I(Ca)或I(Na)。用BAPTA-AM（50微摩尔，30分钟）预孵育或用不可渗透的活性形式的BAPTA（移液管溶液中为10毫摩尔）使细胞负载，可永久性地阻断I(KCa)。在进行BAPTA负载或BAPTA-AM预孵育后，用BAPTA-AM（50微摩尔）灌流也可阻断I(K)（约53%）。总之，我们发现，在培养的牛嗜铬细胞中，BAPTA-AM在作为Ca2+螯合剂发挥作用之前，可直接作用于K+通道，快速且可逆地阻断I(KCa)和I(K)。