Sanders K M, Smith T K
J Physiol. 1986 Aug;377:297-313. doi: 10.1113/jphysiol.1986.sp016188.
The spontaneous electrical activities of circular muscle cells of the canine proximal colon were studied with intracellular micro-electrodes. All circular muscle cells exhibited slow waves at frequencies ranging between 2.8 and 7.0 cycles/min. The slow waves consisted of an upstroke phase followed by a plateau phase of variable duration (2-40 s). Many cells displayed a slow diastolic depolarization, or 'pre-potential' between slow waves. Slow waves spontaneously varied in duration and frequency in most preparations, creating distinctive slow wave patterns. Atropine, 2 X 10(-6) M, decreased the durations of slow waves in many preparations and often changed the pattern to a series of relatively uniform slow waves. A further reduction in mean slow wave duration was produced by additional treatment with tetrodotoxin, 10(-6) M. These results suggested that slow wave duration and pattern were affected by spontaneous discharge from both cholinergic and non-cholinergic excitatory nerves. Transmural nerve stimulation caused a short latency increase in slow wave duration (up to 38 s) that was abolished by atropine. In the presence of atropine, transmural stimulation evoked inhibitory junction potentials that reduced the amplitude and duration of the subsequent slow wave. The slow wave of reduced amplitude was followed by a slow wave of increased duration. The increase in duration of the slow wave did not appear to be related to the size of the preceding hyperpolarization, suggesting it was mediated by the release from non-cholinergic excitatory nerves. All responses to transmural stimulation were blocked by tetrodotoxin. Microejection of acetylcholine on to the muscle adjacent to the micro-electrode also produced an atropine-sensitive increase in slow wave duration. Tissues that had been stored in the cold overnight to reduce intrinsic neural activity exhibited regular slow waves of short duration. It is proposed that the basic myogenic pattern of spontaneous slow wave activity consists of regularly occurring slow waves of short duration (2-5 s). Intrinsic cholinergic and non-cholinergic excitatory nerves appear to modulate slow wave activity in vitro, producing distinctive slow wave patterns of variable instantaneous frequency and duration.
用细胞内微电极研究了犬近端结肠环形肌细胞的自发电活动。所有环形肌细胞均表现出频率在2.8至7.0次/分钟之间的慢波。慢波由一个上升相和随后持续时间可变（2 - 40秒）的平台相组成。许多细胞在慢波之间显示出缓慢的舒张期去极化，即“前电位”。在大多数标本中，慢波的持续时间和频率会自发变化，形成独特的慢波模式。2×10⁻⁶ M的阿托品可缩短许多标本中慢波的持续时间，并常常将模式改变为一系列相对均匀的慢波。用10⁻⁶ M的河豚毒素进一步处理可使平均慢波持续时间进一步缩短。这些结果表明，慢波的持续时间和模式受胆碱能和非胆碱能兴奋性神经的自发放电影响。跨壁神经刺激可使慢波持续时间短暂增加（最长可达38秒），阿托品可消除这种增加。在阿托品存在的情况下，跨壁刺激诱发抑制性接头电位，该电位可降低随后慢波的幅度和持续时间。幅度降低的慢波之后是持续时间增加的慢波。慢波持续时间的增加似乎与先前超极化的大小无关，提示其由非胆碱能兴奋性神经释放介导。对跨壁刺激的所有反应均被河豚毒素阻断。向微电极附近的肌肉微量注射乙酰胆碱也会使慢波持续时间出现阿托品敏感的增加。为降低内在神经活动而在冷环境中过夜保存的组织表现出持续时间短的规则慢波。有人提出，自发慢波活动的基本肌源性模式由持续时间短（2 - 5秒）的规则出现的慢波组成。内在的胆碱能和非胆碱能兴奋性神经似乎在体外调节慢波活动，产生具有可变瞬时频率和持续时间的独特慢波模式。
