SIGNAL TRANSDUCTION IN THE PANCREATIC DUCT SYSTEM

目前尚不清楚细胞内信号转导的分子机制。 排泄物的杯状细胞和分泌重碳酸盐的主细胞 胰腺外分泌的导管上皮，尽管它们在 精制胰液。来自以下方面的输入的机制 中枢神经系统调节神经递质的调节作用 胃肠激素，如促胰液素，尤其鲜为人知。在……里面 这项拟议的研究，最近开发的孤立和 培养的豚鼠胰管上皮细胞将被利用来 确定生理调节因子和细胞内信使 控制导管粘蛋白和碳酸氢盐的分泌，并确定细胞 识别出的信号转导的目标级联。在这些研究中 导管碳酸氢盐分泌的潜在激动剂对血管紧张素转换酶的影响 将测定细胞内游离钙和环核苷酸水平 环核苷酸和肌醇之间的潜在相互作用也是如此 磷脂介导的信号通路。三维动力学 由激动剂引起的钙变化将通过新的 发展中的视频率激光扫描共聚焦显微镜技术 (LSCM)，使用荧光钙探针。的细胞靶标 确定的细胞内信号分子将被定义为 特别注意阴阳离子交换机理和 使用同位素通量测量和激光扫描共聚焦显微镜测量阴离子通道。的效果 推测的生理调节和细胞内信使 将使用LSCM和pH敏感来检测细胞内的pH 荧光染料。激动剂诱导高脚杯释放粘蛋白的动力学 分离的胰管中的细胞将通过合并的 固相放射免疫分析、形态计量学和共聚焦方法 显微镜。这些实验将提供一个详细的图像 副交感神经系统的细胞内机制 胃肠激素通过以下途径调节碳酸氢盐和粘蛋白的分泌 胰腺导管的上皮细胞以及提供必要的 未来对这些信号通路的扰动研究的背景 出现在胰腺疾病中，如囊性纤维化和胰腺- 提提斯。

Little is known of the molecular mechanisms of signal transduction in the goblet cells and bicarbonate-secreting principal cells of the excretory duct epithelium of the exocrine pancreas, despite their central role in elaboration of pancreatic juice. The mechanisms through which input from the central nervous system modulates the regulatory effects of gastrointestinal hormones such as secretin are particularly obscure. In the proposed research, the recently developed model of isolated and cultured guinea pig pancreatic duct epithelial cells will be exploited to identify physiological regulators and intracellular messengers that control ductal mucin and bicarbonate secretion and to define the cellular targets of the identified signal transduction cascades. In these studies the effects of potential agonists of ductal bicarbonate secretion on intracellular free Ca2+ and cyclic nucleotide levels will be determined as will potential interactions between cyclic nucleotide- and inositol phospholipid-mediated signaling pathways. The three dimensional kinetics of calcium changes induced by agonists will be examined through the newly developed technology of video rate laser scanning confocal microscopy (LSCM), using fluorescent calcium probes. The cellular targets of identified intracellular signaling molecules will be defined, with particular attention directed to anion and cation exchange mechanisms and anion channels using isotope flux measurements and LSCM. Effects of putative physiological regulators and intracellular messengers on intracellular pH will be examined using LSCM and pH-sensitive fluorochromes. The kinetics of agonist-induced mucin release from goblet cells in isolated pancreatic ducts will be examined through the combined approaches of solid phase radioimmune assay and morphometry and confocal microscopy. These experiments will provide a detailed picture of the intracellular mechanisms through which the parasympathetic nervous system and gastrointestinal hormones regulate bicarbonate and mucin secretion by the epithelium of the pancreatic ducts as well as providing a necessary context for future studies on perturbations of these signaling pathways that occur in pancreatic diseases such as cystic fibrosis and pancrea- titis.