The experiments were perfomed on transvcrsus abdominis muscle of Elaphe dione by subendothelial recording. The results indicate that in snake motor nerve endings there exist four types of K* channels, i.e. voltage-dep...The experiments were perfomed on transvcrsus abdominis muscle of Elaphe dione by subendothelial recording. The results indicate that in snake motor nerve endings there exist four types of K* channels, i.e. voltage-dependent fast and slow K+ channels, Ca2 +-activated K+ channel and ATP-sensitive K+ channel, (i) The typical wave form of snake terminal current was the double-peaked negativity in standard solution. The first peak was at-tributed to Na influx (INa) in nodes of Ranvier. The second one was blocked by 3, 4-aminopyridine (3, 4-DAP) or te-traethylammonium (TEA), which corresponded to fast K+ outward current (IKF) through the fast K* channels in terminal part, (ii) After IKF as well as the slow K+ current (IKS) were blocked by 3, 4-DAP, the TEA-sensitive Ca2+-dependent K+ current (IK(Ca)) passing through Ca2+-activated K+ channel was revealed, whose amplitude depended on [K+ ]and [Ca2+ ] It was blocked by Ba2+ , Cd2+ or Co2+ . (iii) IK.F and IK(Ca) were blocked by TEA, while IK.S was retained.展开更多
Pinellia ternata lectin (PTL) extracted from the fresh juice of rhizome of pinellia ternata used as a traditional Chinese medicine facilitated the quantal release of acetylcholine (ACh) in the mouse motor nerve termin...Pinellia ternata lectin (PTL) extracted from the fresh juice of rhizome of pinellia ternata used as a traditional Chinese medicine facilitated the quantal release of acetylcholine (ACh) in the mouse motor nerve terminals and formed cation channels in artificial lipid bilayer. Here we report the action of PTL on presynaptic membrane currents of motor nerve terminals.The experiments were performed on the intercostal nerve triangularis sterni muscle preparations. By means of the perineurial recording, the effects of PTL on the sodium current in the preterminal part , three potassium currents and two calcium currents generated from the nerve terminals were investigated. The results show that PTL increases voltage-dependent fast Ca2+ current (ICa,f), Na+ current (INa) and Ca2+-acti-vated K+ current (IK,Ca) without action on either the voltage-dependent fast K+ current (IK,f) or the slow K+ current (IK,S). These effects are irreversible, but can be reversed by mannan, the specific binding sugar for PTL.The展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘The experiments were perfomed on transvcrsus abdominis muscle of Elaphe dione by subendothelial recording. The results indicate that in snake motor nerve endings there exist four types of K* channels, i.e. voltage-dependent fast and slow K+ channels, Ca2 +-activated K+ channel and ATP-sensitive K+ channel, (i) The typical wave form of snake terminal current was the double-peaked negativity in standard solution. The first peak was at-tributed to Na influx (INa) in nodes of Ranvier. The second one was blocked by 3, 4-aminopyridine (3, 4-DAP) or te-traethylammonium (TEA), which corresponded to fast K+ outward current (IKF) through the fast K* channels in terminal part, (ii) After IKF as well as the slow K+ current (IKS) were blocked by 3, 4-DAP, the TEA-sensitive Ca2+-dependent K+ current (IK(Ca)) passing through Ca2+-activated K+ channel was revealed, whose amplitude depended on [K+ ]and [Ca2+ ] It was blocked by Ba2+ , Cd2+ or Co2+ . (iii) IK.F and IK(Ca) were blocked by TEA, while IK.S was retained.
基金Project supported by the National Natural Science Foundation of China.
文摘Pinellia ternata lectin (PTL) extracted from the fresh juice of rhizome of pinellia ternata used as a traditional Chinese medicine facilitated the quantal release of acetylcholine (ACh) in the mouse motor nerve terminals and formed cation channels in artificial lipid bilayer. Here we report the action of PTL on presynaptic membrane currents of motor nerve terminals.The experiments were performed on the intercostal nerve triangularis sterni muscle preparations. By means of the perineurial recording, the effects of PTL on the sodium current in the preterminal part , three potassium currents and two calcium currents generated from the nerve terminals were investigated. The results show that PTL increases voltage-dependent fast Ca2+ current (ICa,f), Na+ current (INa) and Ca2+-acti-vated K+ current (IK,Ca) without action on either the voltage-dependent fast K+ current (IK,f) or the slow K+ current (IK,S). These effects are irreversible, but can be reversed by mannan, the specific binding sugar for PTL.The
