摘要
应用全细胞膜片钳技术研究低浓度辣椒素(capsaicin,cAP)对单个豚鼠心室肌细胞L-型钙电流的影响及其作用机制。CAP(1-25 nmol/L)可浓度依赖性增加电压依赖性的ICa-L的峰值并下移I-V曲线。CAP 1,10,25 nmol/L使ICa-L最大峰值分别由-9.67±0.7pA/pF增至-10.21±0.8 pA/pF(P>0.05),-11.37±0.8 pA/pF和-12.84±0.9 pA/pt(P<0.05)。CAP 25 nmol/L可明显使稳态激活曲线左移,激活中点电压(V0.5)由-20.76±2.0mV变至-26.71±3.0mV(P<0.05),表明低浓度CAP改变了钙通道激活的电压依赖性。CAP25 nmol/L对电压依赖性稳态失活曲线和ICa-L从失活状态下复活过程无明显影响。辣椒素受体(VRl)阻断剂钌红(RR,10 μmol/L可阻断低浓度辣椒素的效应。以上结果表明,低浓度辣椒素使钙通道稳态激活曲线左移,增加ICa-L这一效应可能由VR1介导。
The purpose of this study was to examine the effects of low-dose capsaicin (CAP) on L-type calcium current (ICu- L) in guinea pig ventricular myocytes and the underlying mechanism. ICa-L was examined in isolated single guinea pig ventricular myocytes by using whole-cell patch clamp technique. CAP (1-25 nmol/L) increased the voltage-dependently activated peak amplitude of ICa-L and downshifted the current-voltage (I-V) curve. CAP (1,10,25 nmol/L) increased the peak amplitude of ICa-L from -9.67±0.7 pA/pF to -10.21±0.8 pA/pF (P> 0.05), to -11.37±?0.8 pA/pF and to -12.84±0.9 pA/pF (P<0.05), respectively. CAP 25 nmol/L shifted the steady-state activation curve ofICa-Lto the left and changed half activation potential (V0.5) from (-20.76±2.0) mV to (-26.71±2.0) mV (P<0.05), indicating that low-dose CAP may modify the voltage-dependent activation of calcium channel. Low-dose of CAP did not affect the steady-state inactivation curve of ICa-L or half-recovery time of Ca2+ channel from inactivation. Ruthenium red (RR, 10 μmol/L), a vanilloid receptor (VR1) blocker, antagonized the effects of low-dose CAP. These results suggest that low-dose CAP increases ICa-L mainly by shifting its steady-state activation curve to the left. Such effects may be mediated by VR1.
出处
《生理学报》
CAS
CSCD
北大核心
2004年第2期243-247,共5页
Acta Physiologica Sinica
