环磷酸腺苷和蛋白激酶对豚鼠盲肠绦虫微粒体部分钙摄取的影响。

Effects of cyclic AMP and protein kinase on calcium uptake in a microsomal fraction from guinea pig taenia caecum.

作者信息

Hisayama T, Takayanagi I

出版信息

Biochem Pharmacol. 1983 Nov 1;32(21):3197-203. doi: 10.1016/0006-2952(83)90204-6.

Abstract

A microsomal fraction was isolated from guinea pig taenia caecum by differential centrifugation. Activities of ouabain-sensitive (Na+, K+)-ATPase, 5'-nucleotidase and NADPH-cytochrome c reductase were enriched in the microsomal fraction. On the other hand, less cytochrome c oxidase and monoamine oxidase were contained in this fraction. These results suggest that the microsomal fraction used in this study was derived from both sarcolemma and sarcoplasmic reticulum. Ca2+ uptake by this fraction was strictly dependent on the presence of ATP and was facilitated by oxalate. An ATP-regenerating system was required for the determination of Ca2+ uptake, when a lower concentration of ATP (e.g. 0.25 mM) was used. Phosphorylation of the microsomal fraction was doubled when these membranes were incubated in the presence of cyclic AMP plus cyclic AMP-dependent protein kinase (protein kinase). When the microsomal fraction was pretreated with cyclic AMP plus protein kinase, Ca2+ uptake was stimulated. The increases in microsomal phosphorylation and Ca2+ uptake were significantly correlated (P less than 0.01). This stimulation of Ca2+ uptake by microsomal phosphorylation was observed only in the presence of protein kinase, oxalate, and low Ca2+ and Mg2+ concentrations. The results suggest that stimulation of Ca2+ uptake may be the mechanism by which cyclic AMP is involved in beta-adrenergic relaxation of smooth muscle.

摘要

通过差速离心从豚鼠盲肠带分离出微粒体部分。哇巴因敏感的（Na⁺，K⁺）-ATP酶、5'-核苷酸酶和NADPH-细胞色素c还原酶的活性在微粒体部分中得到富集。另一方面，该部分中细胞色素c氧化酶和单胺氧化酶的含量较少。这些结果表明本研究中使用的微粒体部分来源于肌膜和肌浆网。该部分对Ca²⁺的摄取严格依赖于ATP的存在，并受到草酸盐的促进。当使用较低浓度的ATP（例如0.25 mM）时，测定Ca²⁺摄取需要ATP再生系统。当这些膜在环磷酸腺苷加环磷酸腺苷依赖性蛋白激酶（蛋白激酶）存在下孵育时，微粒体部分的磷酸化增加了一倍。当微粒体部分用环磷酸腺苷加蛋白激酶预处理时，Ca²⁺摄取受到刺激。微粒体磷酸化和Ca²⁺摄取的增加显著相关（P小于0.01）。仅在存在蛋白激酶、草酸盐以及低Ca²⁺和Mg²⁺浓度的情况下，观察到微粒体磷酸化对Ca²⁺摄取的这种刺激作用。结果表明，Ca²⁺摄取的刺激可能是环磷酸腺苷参与平滑肌β-肾上腺素能舒张的机制。