锰离子（Mn²⁺）在离子载体A23187存在下对豚鼠结肠带的作用。

Actions of Mn(2+) in the presence of ionophore A23187 in taenia coli of guinea-pig.

作者信息

Nasu T, Magami G

机构信息

Department of Veterinary Pharmacology, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753, Japan.

出版信息

Pharmacol Res. 2000 Apr;41(4):397-403. doi: 10.1006/phrs.1999.0616.

DOI:10.1006/phrs.1999.0616

PMID:10704262

Abstract

In this work, we have investigated whether Mn(2+)enters the cytoplasm in the presence of ionophore for divalent cations, A23187 and induces contraction of taenia coli. In Ca(2+)-free, 60 m m K(+)medium, the application of 5 m m Mn(2+)evoked contraction and a concomitant increase in Mn(2+)influx into the cytoplasm. However, in Ca(2+)-free medium, the application of 5 m m Mn(2+)in the presence of 1x10(-5)m A23187 did not evoke both contraction and Mn(2+)influx. These results suggest that Mn(2+)penetrates through Ca(2+)channels in a state of membrane depolarization with K(+)and activates the contractile proteins in taenia coli. However, Mn(2+)does not enter the cytoplasm in the presence of ionophore A23187 and then does not induce contraction.

摘要

在这项研究中，我们探究了在存在二价阳离子载体A23187的情况下，Mn(2+)是否会进入细胞质并诱导结肠带收缩。在无Ca(2+)、60 mM K(+)的培养基中，施加5 mM Mn(2+)会引发收缩，并伴随Mn(2+)流入细胞质的增加。然而，在无Ca(2+)的培养基中，在1×10(-5)M A23187存在的情况下施加5 mM Mn(2+)，既不会引发收缩，也不会导致Mn(2+)流入。这些结果表明，Mn(2+)在与K(+)导致膜去极化的状态下通过Ca(2+)通道渗透，并激活结肠带中的收缩蛋白。然而，在离子载体A23187存在的情况下，Mn(2+)不会进入细胞质，因此不会诱导收缩。