Yoshida M, Ishiura S
J Pharmacobiodyn. 1981 Oct;4(10):751-8. doi: 10.1248/bpb1978.4.751.
The responses of isolated gal bladder to transmural electrical stimulation with rectangular pulses (50 volt, 0.5 ms) of 30 Hz for 10 s at intervals of 30 min were observed for 5 to 6 hours continuously and compared for different values of resting tonus in Krebs solution at 27 degrees C and 37 degrees C Krebs solution, the resting tonus increased gradually with time and became stable at 0.56 +/- 0.07 g (mean +/- S.D.) after 5 h. In 37 degrees C Krebs solution, the resting tonus increased gradually with time and became stable at 1.48 +/- 0.49 g (mean +/- S.D.) to 1.5 +/- 0.19 g (mean +/- S.D.) after 5 h. Monophasic contraction was observed when the resting tonus was lower than 1.49 +/- 0.15 g (mean +/- S.D.), but above this value, biphasic response consisting of contraction and relaxation was observed. Both monophasic and biphasic responses were blocked by atropine and tetrodotoxin. Physostigmine enhanced monophasic contraction, increased the duration of contraction, and abolished the relaxation of biphasic contractile response. The results suggest that contractile response of isolated guinea-pig gall bladder to transmural electrical stimulation was directly induced by acetylcholine released from postganglionic cholinergic fibers. Transmural electrical stimulation with rectangular pulses (50 volt, 0.5 ms) at 10, 20, 30 or 40 Hz for 10 s induced biphasic response in which the contraction varied with frequency, peaking at about 30 Hz, while the relaxation was almost constant. Biphasic relaxation was reduced or inhibited by 2,4-dinitrophenol, ouabain, or K+ -free solution. This suggests that the relaxation phase of the biphasic response induced by transmural electrical stimulation was an active process.
持续5至6小时观察了离体胆囊对30Hz、持续10秒的矩形脉冲（50伏，0.5毫秒）跨壁电刺激的反应，刺激间隔为30分钟，并比较了27℃和37℃ Krebs溶液中不同静息张力值下的反应。静息张力随时间逐渐增加，5小时后稳定在0.56±0.07克（平均值±标准差）。在37℃ Krebs溶液中，静息张力随时间逐渐增加，5小时后稳定在1.48±0.49克（平均值±标准差）至1.5±0.19克（平均值±标准差）。当静息张力低于1.49±0.15克（平均值±标准差）时观察到单相收缩，但高于此值时，观察到由收缩和舒张组成的双相反应。单相和双相反应均被阿托品和河豚毒素阻断。毒扁豆碱增强了单相收缩，增加了收缩持续时间，并消除了双相收缩反应的舒张。结果表明，离体豚鼠胆囊对跨壁电刺激的收缩反应是由节后胆碱能纤维释放的乙酰胆碱直接诱导的。10、20、30或40Hz、持续10秒的矩形脉冲（50伏，0.5毫秒）跨壁电刺激诱导双相反应，其中收缩随频率变化，在约30Hz时达到峰值，而舒张几乎恒定。双相舒张被2,4-二硝基苯酚、哇巴因或无钾溶液降低或抑制。这表明跨壁电刺激诱导的双相反应的舒张期是一个活跃过程。
