ELECTRICAL CONTROL OF PYLORIC MOTILITY

提出实验研究的基本电生理学的 犬幽门括约肌 幽门的电活动 这是一个复杂的问题，以前没有充分描述过。 细胞外记录或少数报道的细胞内记录 问题研究 我们已经制定了横截面的准备工作， 幽门肌层，其允许细胞内 微电极，以表征在任何 幽门环内的点或穿过厚度的任何水平 的肌肉。 幽门电图的完整分析 将执行波形。 初步研究显示 幽门肌是由胃窦电活动控制的， 当幽门分离时， 从远端胃窦。 我们还观察到慢波 当它们通过圆形层传播时振幅衰减， 远端穿过幽门环 环状肌肉的体积 似乎是一个被动的合胞体， 产生或再生慢波活动。 这就提出了一个 幽门是如何被激活的，以及它的活动是如何被激活的。 与胃蠕动活动相协调。 实验来 将回答这些问题。 起源和 电事件的传播机制将是 测定 我们还将研究电力监管 幽门内的活动，特别是神经递质 荷尔蒙的影响会影响自发性事件， 电事件的传播。 最初的假设是， 神经调节控制活动的频率， 起搏点更接近幽门，但振幅 以及这些事件的传播范围 进入幽门环取决于神经和激素 合胞体电缆特性和兴奋性的调节 机制等 我们还将确定 电气和机械事件。 最后，我们将尝试 将电生理特征与结构 测量. 我们希望能调和电反应， 神经刺激，测量神经支配密度， 索参数对合胞体结构特征的影响。 这些实验应该为理解 控制幽门运动的基本机制，有助于解释 幽门在调节胃排空中的作用。

Experiments are proposed to study the basic electrophysiology of canine pyloric sphincter. The electrical activity of the pylorus is complicated and has not been adequately described by previous extracellular recordings or by the few reported intracellular studies. We have developed cross-sectional preparations of the pyloric muscularis which allow precise placement of intracellular microelectrodes to characterize the electrical activity at any point within the pyloric ring or at any level through the thickness of the muscle. A complete analysis of pyloric electrical waveforms will be performed. Preliminary studies have revealed that pyloric muscles are paced by antral electrical activity and that much of the pylorus may be quiescent when it is uncoupled from the distal antrum. We have also observed that slow waves decay in amplitude as they propogate through the circular layer or distally through the pyloric ring. The bulk of the circular muscle of the pylorus appears to be a passive syncytium which does not generate or regenerate slow wave activity. This raises the question of how the pylorus is activated, and how its activity is coordinated with gastric peristaltic activity. Experiments to answer these questions will be performed. The origin and mechanisms of propagation of electrical events will be determined. We will also investigate regulation of electrical activity within the pylorus, specifically how neurotransmitters and hormonal influences affect spontaneous events and the propagation of electrical events. An initial hypothesis is that neural regulation controls the frequency of activity at the pacemaker sites more proximal to the pylorus, but the amplitude of electrical events and the extent of the spread of these events into the pyloric ring depends upon neural and hormonal conditioning of the syncytial cable properties and excitability mechanisms. We will also determine the relationship between electrical and mechanical events. Finally we will attempt to correlate electrophysiological characteristics with structural measurements. We hope to reconcile electrical responses to neural stimulation with measurements of innervation density and cable parameters to structural characteristics of the syncytium. These experiments should provide a basis for understanding the basic mechanisms controlling pyloric motility and help to explain the role of the pylorus in regulating gastric emptying.