Qu Y, Campbell D L, Himmel H H, Strauss H C
Department of Medicine, Duke University Med. Center, Durham, NC 27710.
Adv Exp Med Biol. 1993;346:11-8. doi: 10.1007/978-1-4615-2946-0_2.
The effects of extracellular ATP on the L-tpe Ca2+ current (ICa), action potential, and resting and intracellular Ca2+ levels were examined in enzymatically isolated myocytes from the right ventricles of ferrets. Extracellular ATP decreased the peak amplitude of ICa in a time- and concentration-dependent manner. The concentration-response relationship for ATP inhibition of ICa was well described by a conventional Michaelis-Menten relationship with a half maximal inhibitory concentration of 1 microM and a maximal effect of 50%. Extracellular ATP did not change the resting myoplasmic Ca2+ levels; however, it did decrease the Ca2+ transient. The effects of extracellular ATP were mediated independently of adenosine A1 receptors and a pertussis-toxin sensitive G protein. Pharmacological characterization of receptor subtype using ATP analogs was consistent with ATP binding to a P2Y type receptor.
在雪貂右心室酶分离的心肌细胞中，研究了细胞外ATP对L型钙电流（ICa）、动作电位以及静息和细胞内钙水平的影响。细胞外ATP以时间和浓度依赖性方式降低ICa的峰值幅度。ATP对ICa抑制作用的浓度-反应关系可用传统的米氏关系很好地描述，其半数最大抑制浓度为1微摩尔，最大效应为50%。细胞外ATP未改变静息肌浆钙水平；然而，它确实降低了钙瞬变。细胞外ATP的作用独立于腺苷A1受体和百日咳毒素敏感的G蛋白介导。使用ATP类似物对受体亚型进行的药理学表征与ATP与P2Y型受体结合一致。
