NEUROEFFECTOR TRANSMISSION IN A SIMPLE SALIVARY GLAND

这项基础研究计划的长期目标是一个根本 了解参与的生物物理和生物化学过程， 外分泌腺功能的神经元控制。 在本申请中，我们 我建议继续对一个相对简单的唾液腺进行研究 系统从水生蜗牛Helisoma trivolvis提供了一些 作为一个模型系统的重要技术优势。 在第一系列实验中，我们将使用以下技术： 跨膜电压的多位点光学记录（MSORTV） 同时记录多达124个独立腺体的电活动 1）描述和量化被动传播， 腺泡和导管腺区域之间的电流，2）绘制终末场 两个效应神经元的腺体（SEN的），并确定程度 终端字段重叠，和3）评估时间分散的影响 的SEN神经终末棘波的诱发电反应， 腺泡和导管细胞。 在第二个系列的实验中，已被添加到本修订 申请，我们建议继续我们的调查，最近 鉴定出对蜗牛唾液高度兴奋的纳米肽 腺，并可作为发射器的物质释放的SEN的， 神经腺连接处 常规免疫组织化学技术 将用于确定是否存在该肽（SCPB） 在SEN和唾液腺中。 我们还将调查大型 SCPB诱发的II型腺体反应的后超极化， 确定它是否代表Ca+2介导的K+电导。 中 相关的一系列实验，我们希望比较焦点的影响， 应用SCPB和乙酰胆碱，看看这些兴奋性腺体是否 物质，当同时存在时，促进电和/或 腺泡细胞的分泌反应。 在第三个系列的实验中，这也是在修订版中增加的， 我们将使用一种新的荧光指示剂（QUIN 2/AM）来监测 神经元和 药理刺激 通过使用传统的离子感应 电极，我们将描述刺激之间的相互关系， 电活动、细胞内钙和电解质分泌。

The long-term goal of this basic research program is a fundamental understanding of the biophysical and biochemical processes involved in the neuronal control of exocrine gland function. In this application, we propose to continue ongoing studies of a relatively simple salivary gland system from the aquatic snail Helisoma trivolvis which offers a number of important technical advantages as a model system. In the first series of experiments, we will use the technique of Multiple-Site Optical Recording of Transmembrane Voltage (MSORTV) to simultaneously record electrical activity in up to 124 separate gland regions in order to: 1) characterize and quantify the passive spread of current between acinar and ductal gland regions, 2) map the terminal fields of the two effector neurons to the gland (SEN's) and determine the extent of terminal field overlap, and 3) assess the effects of temporal dispersion of the SEN nerve terminal spikes on the evoked electrical response of acinar and ductal cells. In the second series of experiments, that have been added to this revised application, we propose to continue our investigations of a recently identified nanopeptide that is highly excitatory for the snail salivary gland and may serve as the transmitter substance released by the SEN's at the neuroglandular junction. Conventional immunohistochemical techniques will be used to determine the presence (or absence) of this peptide (SCPB) in the SEN's and in the salivary gland. We will also investigate the large after-hyperpolarization of the Type II gland response evoked by SCPB to determine whether it represents a Ca+2-mediated K+ conductance. In a related series of experiments, we wish to compare the effects of focal application of SCPB and acetylcholine to see if these excitatory gland substances, when presented simultaneously, facilitate the electrical and/or secretory response of acinar cells. In a third series of experiments, which have also been added in revision, we will use a new fluorescent indicator (QUIN 2/AM) to monitor the cytosolic concentration of ionized calcium following neuronal and pharmacological stimulation. Through the use of conventional ion-sensing electrodes, we will characterize the interrelationship between stimulation, electrical activity, intracellular calcium and electrolyte secretion.