Lang R J
Br J Pharmacol. 1979 Sep;67(1):39-49.
1 The effects of calcium and magnesium ions and temperature on the peak amplitude of the nonadrenergic, noncholinergic inhibitory junction potential, evoked by a single stimulus, or paired transmural stimuli, were examined in the circular muscle of guinea-pig small intestine.2 The peak amplitude of the inhibitory junction potential (i.j.p.) could be decreased by lowering the external concentration of calcium or by raising the external magnesium concentration (at 25 degrees C).3 At 25 degrees C, the second of a pair of i.j.ps was larger than the first at short intervals (<0.2 s), but smaller at larger intervals (0.2 to 20 s). Enhancement of the second (test) response decayed exponentially with a time constant of 87 ms. Depression of the test i.j.p. was maximal at 0.4 s and then recovered exponentially with a time constant of 11 s.4 In low calcium or high magnesium solution, depression of the test i.j.p. decreased without any change in the rate of recovery from depression.5 Despite the slow rate of recovery from depression after a single conditioning response, transmitter output could be maintained during low-frequency repetitive stimulation.6 The peak amplitude of the i.j.p. increased as the temperature was raised to 35 degrees C (Q(10) = 1.5).7 In contrast to the neuromuscular junction, the depression of the second of a pair of i.j.ps decreased as the temperature was raised. At 35 degrees C the test i.j.p. was larger than the conditioning i.j.p. for most stimulus intervals (1 to 20 s).8 The results suggest that the rate of replenishment of the store of inhibitory transmitter is sensitive to both temperature and repetitive stimulation.
在豚鼠小肠环行肌中，研究了钙、镁离子及温度对由单个刺激或成对透壁刺激诱发的非肾上腺素能、非胆碱能抑制性接头电位峰值幅度的影响。
通过降低细胞外钙浓度或提高细胞外镁浓度（在25℃时），抑制性接头电位（i.j.p.）的峰值幅度会降低。
在25℃时，成对i.j.p.中的第二个在短间隔（<0.2秒）时比第一个大，但在长间隔（0.2至20秒）时较小。第二个（测试）反应的增强以87毫秒的时间常数呈指数衰减。测试i.j.p.的抑制在0.4秒时最大，然后以11秒的时间常数呈指数恢复。
在低钙或高镁溶液中，测试i.j.p.的抑制减少，而从抑制中恢复的速率没有任何变化。
尽管在单次条件反应后从抑制中恢复的速率较慢，但在低频重复刺激期间递质输出仍可维持。
随着温度升高至35℃，i.j.p.的峰值幅度增加（Q(10)=1.5）。
与神经肌肉接头不同，随着温度升高，成对i.j.p.中第二个的抑制减少。在35℃时，对于大多数刺激间隔（1至20秒），测试i.j.p.大于条件i.j.p.。
结果表明，抑制性递质储存的补充速率对温度和重复刺激均敏感。
