Effects of dantrolene and its derivatives on Ca<sup>2+</sup>
release from the sarcoplasmic reticulum of mouse skeletal muscle fibres
作者:Takaaki Ikemoto、Takamitsu Hosoya、Hiroshi Aoyama、Yasutaka Kihara、Masaaki Suzuki、Makoto Endo
DOI:10.1038/sj.bjp.0704307
日期:2001.10
We analysed the effect of dantrolene (Dan) and five newly synthesized derivatives (GIFs) on Ca2+ release from the sarcoplasmic reticulum (SR) of mouse skeletal muscle.
In intact muscles, GIF‐0185 reduced the size of twitch contraction induced by electrical stimulation to the same extent as Dan. GIF‐0082, an azido‐functionalized Dan derivative, also inhibited twitch contraction, although the extent of inhibition was less than that of Dan and of GIF‐0185.
In skinned fibres, Dan inhibited Ca2+‐induced Ca2+ release (CICR) under Mg2+‐free conditions at room temperature. In contrast, GIF‐0082 and GIF‐0185 showed no inhibitory effect on CICR under the same conditions.
Dan‐induced inhibition of CICR was not affected by the presence of GIF‐0082, whereas it was diminished in the presence of GIF‐0185.
GIF‐0082 and GIF‐0185 significantly inhibited clofibric acid (Clof)‐induced Ca2+ release, as did Dan.
Several Dan derivatives other than GIF‐0082 and GIF‐0185 showed an inhibitory effect on twitch tension but not on the CICR mechanism. All of these derivatives inhibited Clof‐induced Ca2+ release.
The magnitudes of inhibition of Clof‐induced Ca2+ release by all Dan derivatives were well correlated with those of twitch inhibition. This supports the notion that the mode of Clof‐induced opening of the RyR‐Ca2+ release channel may be similar to that of physiological Ca2+ release (PCR).
These results indicate that the difference in opening modes of the RyR‐Ca2+ release channel is recognized by certain Dan derivatives.
British Journal of Pharmacology (2001) 134, 729–736; doi:10.1038/sj.bjp.0704307
我们分析了丹特罗伦(Dan)及其五种新合成的衍生物(GIFs)对小鼠骨骼肌肌质网(SR)中钙离子(Ca²+)释放的作用。
在完整肌肉中,GIF-0185将电刺激诱导的 twitch 收缩幅度降低至与 Dan 相同的程度。另一种叠氮功能化的 Dan 衍生物 GIF-0082也抑制了 twitch 收缩,尽管其抑制程度低于 Dan 和 GIF-0185。
在去膜肌纤维中,Dan 在无 Mg²+ 的室温条件下抑制钙诱导的钙释放(CICR)。与此相反,GIF-0082 和 GIF-0185 在相同条件下对 CICR 没有抑制作用。
Dan 对 CICR 的抑制作用不受 GIF-0082 的存在影响,但在 GIF-0185 存在时被减弱。
GIF-0082 和 GIF-0185 显著抑制了氯芬酸(Clof)诱导的 Ca²+ 释放,与 Dan 作用相同。
除 GIF-0082 和 GIF-0185 外,其他几种 Dan 衍生物也抑制 twitch 张力,但不影响 CICR 机制。所有这些衍生物均抑制 Clof 诱导的 Ca²+ 释放。
所有 Dan 衍生物对 Clof 诱导的 Ca²+ 释放的抑制作用程度与对 twitch 的抑制作用程度密切相关。这支持了 Clof 诱导的 RyR-Ca²+ 释放通道开启模式可能与生理状态下 Ca²+ 释放(PCR)相似的观点。
这些结果表明,某些 Dan 衍生物能够识别 RyR-Ca²+ 释放通道开启模式的差异。
*《英国药理学杂志》(2001)134卷,729–736页;doi:10.1038/sj.bjp.0704307