ω-芋螺毒素IVA可阻断牛嗜铬细胞中的烟碱型受体通道。

omega-Agatoxin IVA blocks nicotinic receptor channels in bovine chromaffin cells.

作者信息

Granja R, Fernández-Fernández J M, Izaguirre V, González-García C, Ceña V

机构信息

Departamento de Farmacología, Universidad de Alicante, Spain.

出版信息

FEBS Lett. 1995 Mar 27;362(1):15-8. doi: 10.1016/0014-5793(95)00149-4.

DOI:10.1016/0014-5793(95)00149-4

PMID:7698345

Abstract

We have studied the contribution of P-type voltage-dependent Ca2+ channels to both catacholamine (CA) and ATP secretion from bovine chromaffin cells induced by high K+ or nicotine using omega-agatoxin IVA, a selective blocker of P-type voltage-dependent Ca2+ channels. We found that high K+ (75 mM) induced the release of about 13% of norepinephrine, 5% epinephrine and 11% ATP, and that omega-agatoxin (100 nM) did not affect this secretion. However, both nicotine-induced CA and ATP secretion were significantly blocked (about 50%) by omega-agatoxin IVA (100 nM). In addition, this toxin also reversibly blocked (about 70%) the inward current induced by nicotine in bovine chromaffin cells. The results suggest that, besides its known action of blocking P-type voltage-dependent channels, omega-agatoxin is a potent and reversible blocker of the nicotinic receptor channel in chromaffin cells, and that this action would explain the blockade of nicotine-induced secretion.

摘要

我们使用ω-芋螺毒素IVA（一种P型电压依赖性Ca2+通道的选择性阻滞剂），研究了P型电压依赖性Ca2+通道对高钾或尼古丁诱导的牛嗜铬细胞中儿茶酚胺（CA）和ATP分泌的作用。我们发现，高钾（75 mM）诱导释放约13%的去甲肾上腺素、5%的肾上腺素和11%的ATP，而ω-芋螺毒素（100 nM）不影响这种分泌。然而，ω-芋螺毒素IVA（100 nM）显著阻断了尼古丁诱导的CA和ATP分泌（约50%）。此外，这种毒素还可逆地阻断了尼古丁在牛嗜铬细胞中诱导的内向电流（约70%）。结果表明，除了其已知的阻断P型电压依赖性通道的作用外，ω-芋螺毒素是嗜铬细胞中烟碱受体通道的一种有效且可逆的阻滞剂，并且这种作用可以解释对尼古丁诱导分泌的阻断。