Levi R C, Alloatti G, Fischmeister R
Dipartimento di Biologia Animale, Università di Torino, Italy.
Pflugers Arch. 1989 Apr;413(6):685-7. doi: 10.1007/BF00581823.
The effect of intracellular perfusion with cyclic GMP (cGMP) on Ca current (Ica) was investigated in Cs-loaded isolated cells from guinea pig ventricle using the whole-cell patch-clamp technique and a perfused patch pipette. cGMP (5 microM) strongly reduced Ica which had been elevated by intracellular perfusion with 50 microM of either cyclic AMP (cAMP) or its hydrolysis-resistant analog 8-Bromo-cAMP. In addition, cGMP prevented the stimulation of Ica by IBMX, a phosphodiesterase inhibitor. The membrane permeant cGMP analog 8-Bromo-cGMP (100 microM), when applied outside the cell, also antagonized the stimulatory effect of IBMX on Ica. It is concluded that cGMP inhibits Ica in guinea pig ventricular cells by a mechanism different from the activation of a cGMP-stimulated phosphodiesterase recently found in frog ventricular cells.
运用全细胞膜片钳技术及灌注式膜片吸管，在豚鼠心室的铯负载分离细胞中研究了细胞内灌注环磷酸鸟苷（cGMP）对钙电流（Ica）的影响。cGMP（5微摩尔）强烈降低了Ica，该Ica已因细胞内灌注50微摩尔的环磷酸腺苷（cAMP）或其抗水解类似物8-溴-cAMP而升高。此外，cGMP可防止磷酸二酯酶抑制剂异丁基甲基黄嘌呤（IBMX）对Ica的刺激作用。膜通透性cGMP类似物8-溴-cGMP（100微摩尔）在细胞外应用时，也可拮抗IBMX对Ica的刺激作用。得出的结论是，cGMP通过一种不同于最近在蛙心室细胞中发现的cGMP刺激的磷酸二酯酶激活的机制来抑制豚鼠心室细胞中的Ica。
