NEUROEFFECTOR TRANSMISSION IN A SIMPLE SALIVARY GLAND

这一基础研究计划的长期目标是一个基本的 对生物物理和生物化学过程的理解 神经元对外分泌腺功能的控制。在此应用程序中，我们 建议继续进行对相对简单的唾液腺的研究 系统由水生蜗牛Helisoma trivolvis提供了许多 作为模型系统的重要技术优势。 在第一系列实验中，我们将使用 跨膜电压的多点光学记录(MSORTV) 同时记录多达124个独立腺体的电活动 区域，以便：1)表征和量化被动传播 腺泡和导管腺区之间的电流，2)绘制终端场 两个效应神经元对腺的影响(SEN‘s)，并确定程度 以及3)评估时间色散的影响 SEN神经末梢棘波对诱发的电反应的影响 腺泡细胞和导管细胞。 在第二系列实验中，这些实验已添加到修订后的 ，我们建议继续调查最近发生的一起 鉴定出对蜗牛唾液高度兴奋的纳米肽 腺体，并可作为SEN的AT释放的递质物质 神经腺连接。常规免疫组织化学技术 将用于确定该肽(SCPB)的存在(或不存在) 在SEN‘s和唾液腺。我们还将调查大型 SCPB诱发的II型腺体后超极化反应 确定它是否代表由Ca+2介导的K+电导。在一个 相关的一系列实验，我们希望比较聚焦的效果 应用SCPB和乙酰胆碱检测这些兴奋性腺体 物质，当同时存在时，促进电和/或 腺泡细胞的分泌反应。 在第三系列实验中，也加入了修订版， 我们将使用一种新的荧光指示剂(Quin 2/AM)来监测 神经细胞损伤后胞内游离钙离子浓度变化 药理刺激。通过使用传统的离子传感 电极，我们将描述刺激、 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.