一. 本文以離體小白鼠膈神經－橫膈膜標本及胸三角神經－肌標本為材材
料，利用一般藥理學及電生理學技術研究蛇毒waglerin-1 對神經-肌傳導
之作用，並探討其可能的作用機轉。二. Waglerin-1 (1.20-3.99 uM) 可
逆地抑制間接刺激引起之肌收縮反應(indirect twitch tension)，其抑
制的作用與濃度有關，waglerin-1的濃度愈高，其抑制的作用也愈強，
waglerin-1 3.99 uM 可完全抑制間接刺激引起之肌收縮反應。三.
Waglerin-1 (3.99 uM) 亦可完全抑制間接刺激引起之肌動作電位
(action potential)。四. Waglerin-1 (3.99 uM) 不影響橫膈膜靜止膜
電位及直接刺激引起之肌收縮反應 ( direct twitch tension)。五.
Waglerin-1 (1.20-3.99 板電位之振幅(amplitude)。六. Waglerin-1
(0.52-1.20 uM) 可逆地抑制微小終板電位 ( miniature endplate
potential) 之振幅。七. 在切斷膈神經 9-14 天之橫膈膜標本，
waglerin-1 ( 1.20-3.99 uM可抑制乙醯膽鹼引起之肌收縮反應 (muscle
contracture)。八. Waglerin-1 (0.12-0.52 uM) 可抑制微小終板電位之
頻率。九. Waglerin-1 (1.20 nM - 0.40 uM) 可抑制終板電位之量子
數 (quantal content)。十. Waglerin-1 (3.99 uM) 不影響神經末梢之
鈉離子電流.十一. Waglerin-1 (3.99 uM) 不影響神經末梢三種鉀離子
電流：快鉀電流 (fast K current)、慢鉀電流 (slow K current) 及
鈣活化鉀電流 (calcium activated K current)。十二. Waglerin-1
(3.99 uM) 可減少神經末梢快鈣電流 ( fast Ca current)及慢鈣電流
(slow Ca current) 之振幅。十三. 本篇實驗結果顯示， waglerin-1
具有抑制運動神經末梢釋出乙醯膽鹼的作用，且此作用可能與抑制運動神
經末梢快鈣電流及慢鈣電流有關。高濃度的 waglerin-1 對突觸後乙醯膽
鹼受體也有抑制作用。因此 waglerin-1 的致神經毒性作用機轉可能係
由1. 抑制突觸前乙醯膽鹼釋出，2.抑制突觸後乙醯膽鹼受體，二者協同
作用導致神經－肌傳導阻斷所造成的。

The effects of waglerin-1, a toxin from Trimeresurus wagleri on
the neuromuscular (NM) transmission were studied on the mouse
phrenic nerve diaphragm and triangularis sterninerve-muscle
pre- parations. Waglerin-1 (1.20-3.99 uM) reversibly
inhibited the directly elicited twitch tension of the diaphragm.
The toxin(3.99 uM ) also inhibited indirectly elicited action
potential of the diaphragm. However, the directly elicited
twitch tension and the resting membrane potential of the
diaphragm were not affected by waglerin-1(3.99 uM). The results
above suggested that waglerin-1 neurotoxic but did not have
myotoxic effects. The toxin ( 1.20- 3.99 nM)reversibly
inhibited the amplitude of endplate potential The toxin
(0.52-1.20 uM) also reversibly inhibited the amplitude of
miniature endplate potential,while it decreased the frequency
miniature endplate potential at a lower concentration
(0.12-0.40 uM). Waglerin-1 (1.20 nM -0.40 uM) decreased the
quantal content of endplate potential,too. In chronically
denervated diaphragm, waglerin-1 (1.20-3.99uM) decreased the
acetylcholine induced mu- scle contracture. The perineural
waveforms were recorded with an extra cellular electrode
placed into the perineural sheaths of motor nerves of
triangularis sterni. Waglerin-1 (3.99 uM) did not alter the
waveforms of sodium, fast potassium,slow potassium and calcium
activated potassium currents of the nerve terminal, but it
decreased the fast calcium and slow calcium currents.It was
concluded that waglerin-1 acted on both pre-synaptic and post-
synaptic sites of the mouse motor endplate. The neuro-
toxicity of waglerin-1 may be resulted from the synergistic
effects of both actions.The effects of waglerin-1 on the
calcium currents of motor nerve terminal may contribute to its
action on the pre-synapic transmission.