Satoh M, Takayanagi I, Koike K
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Funabashi, Chiba, Japan.
Jpn J Pharmacol. 2000 Apr;82(4):317-25. doi: 10.1254/jjp.82.317.
We studied the mechanisms and characteristics of the spontaneously evoked intracellular Ca2+ changes (Ca2+ oscillations) in ileal longitudinal smooth muscle from guinea pig. Two-dimensional images of Ca2+ oscillations were obtained at 33-ms intervals with a Ca2+-sensitive fluorescence probe, fluo-3 using the intensified CCD camera. Nicardipine (10-7 M) significantly decreased the maximum level of fluorescence intensity of the Ca2+ oscillations, inhibited the frequency of the oscillations and tended to decrease the basal level of fluorescence intensity. However, tetrodotoxin (3 x 10-7 M) did not affect these oscillations. Phorbol 12,13-dibutyrate (10-7 M) significantly increased the maximum level of fluorescence intensity and the frequency of Ca2+ oscillations, and it changed them to steady and chronometric Ca2+ oscillations. Cyclopiazonic acid (3 x 10-5 M) also significantly increased the frequency of Ca2+ oscillations. Acetylcholine (10-8 M) increased the basal and maximum level of fluorescence intensity and the frequency of Ca2+ oscillations, and accelerated their onset. The increase of basal level of fluorescence intensity was then decreased by cyclopiazonic acid treatment. These results suggest that the augmentation of Ca2+ oscillations is mainly due to the activation of L-type Ca2+ channels, which is modulated by protein kinase C, and that the emptying of intracellular Ca2+ stores may activate the Ca2+ oscillations mediated through the increase of Ca2+ influx in ileal smooth muscle of guinea pig.
我们研究了豚鼠回肠纵行平滑肌中自发诱发的细胞内钙离子变化（钙离子振荡）的机制和特征。使用增强型电荷耦合器件（CCD）相机，以33毫秒的间隔，用钙离子敏感荧光探针fluo-3获取钙离子振荡的二维图像。尼卡地平（10^-7 M）显著降低了钙离子振荡的荧光强度最大水平，抑制了振荡频率，并倾向于降低荧光强度的基础水平。然而，河豚毒素（3×10^-7 M）对这些振荡没有影响。佛波醇12,13-二丁酸酯（10^-7 M）显著提高了荧光强度最大水平和钙离子振荡频率，并将其转变为稳定且有节律的钙离子振荡。环匹阿尼酸（3×10^-5 M）也显著增加了钙离子振荡频率。乙酰胆碱（10^-8 M）增加了荧光强度的基础水平和最大水平以及钙离子振荡频率，并加速了其起始。然后，环匹阿尼酸处理降低了荧光强度基础水平的增加。这些结果表明，钙离子振荡的增强主要是由于L型钙离子通道的激活，其受蛋白激酶C调节，并且细胞内钙离子储存的排空可能通过豚鼠回肠平滑肌中钙离子内流的增加来激活钙离子振荡。
