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EXCITATION-CONTRACTION COUPLING OF GALLBLADDER MUSCLE

胆囊肌的兴奋-收缩耦合

基本信息

批准号：
2015610
负责人：
HENRY PAUL PARKMAN
金额：
$ 9.21万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
1993
资助国家：
美国
起止时间：
1993-01-01 至 1997-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2015610
关键词：
acetylcholine calcium channel calcium flux cats cholecystokinin cholelithiasis disease /disorder model fluorescent dye /probe gallbladder human tissue membrane potentials muscle contraction neural transmission neurohormones neurotransmitters potassium smooth muscle voltage /patch clamp

项目摘要

The objective of this research proposal is to investigate the mechanisms of excitation-contraction coupling in the gallbladder smooth muscle and in doing so, prepare the applicant for a long term career as an independent investigator. Excitation-contraction coupling of gallbladder smooth muscle is particularly important because abnormal gallbladder contractility may play a primary pathophysiologic role in the formation of gallstones. Investigation of excitation-contraction coupling in feline gallbladder smooth muscle will provide a background for studies in human gallbladder smooth muscle in gallstone disease. The specific aims of this project are: 1) to characterize the utilization of intracellular and extracellular calcium sources in excitation-contraction coupling in isolated gallbladder myocytes stimulated by three agonists - acetylcholine, cholecystokinin, and potassium; 2) to determine the transmembrane electrical properties of gallbladder smooth muscle in muscle strips under basal conditions and to determine the effects of classical neurotransmitters and hormones on electromechanical coupling by evaluating the voltage-tension relationships of graded concentrations of extracellular potassium, acetylcholine, and cholecystokinin; 3) to evaluate the effects of endogenous neurotransmitters on intracellular electrical activity and muscle tension of gallbladder smooth muscle using electric field stimulation to activate intrinsic enteric nerves of the gallbladder; and 4) to characterize the excitation-contraction coupling abnormalities in human gallbladder smooth muscle from patients with gallstones. Several sophisticated research techniques will be employed in the conduct of this project: simultaneous intracellular electrical and isometric muscle tension recordings will be performed to investigate the electromechanical coupling of gallbladder smooth muscle; freshly dispersed isolated gallbladder myocytes will be used to measure cell shortening; cytosolic calcium concentrations will be evaluated using the calcium-sensitive fluorescent dye indo-1; and cell membrane calcium channels will be characterized using the whole cell patch clamp technique. In the process of elucidating the mechanisms of gallbladder excitation-contraction coupling, the relationship between cell membrane potential, calcium utilization, membrane calcium currents and gallbladder smooth muscle contraction will be better understood. The candidate is a physician-scientist who is determined to develop a career committed to the study of gastrointestinal motility. To achieve this goal, the candidate will continue to work with and learn from two respected basic scientists in gastrointestinal smooth muscle and cardiac muscle physiology. Interaction with these investigators will provide a stimulating and productive environment, so that the candidate can conduct productive research and position himself to compete successfully for independent extramural funding in the future.

这项研究的目的是探讨机制，胆囊平滑肌的兴奋-收缩偶联，在这样做，准备申请人作为一个长期的职业生涯，独立调查员胆囊兴奋-收缩偶联平滑肌尤其重要，因为异常胆囊收缩性可能在形成中起主要的病理生理作用，胆结石神经元兴奋-收缩偶联的研究猫胆囊平滑肌将为研究提供背景在胆囊结石病中胆囊平滑肌中的作用。具体该项目的目标是：1）描述兴奋-收缩中细胞内外钙源在三种激动剂刺激的分离胆囊肌细胞中偶联，乙酰胆碱、胆囊收缩素和钾; 2）确定胆囊平滑肌跨膜电特性肌肉条在基础条件下，并确定影响经典神经递质和激素对机电耦合的影响通过评估梯度浓度的电压-张力关系，细胞外钾、乙酰胆碱和胆囊收缩素; 3）评价内源性神经递质对细胞内胆囊平滑肌的电活动和肌张力电场刺激以激活肠内神经胆囊;和4）表征兴奋-收缩偶联人胆囊平滑肌的异常胆结石。将采用几种复杂的研究技术在这个项目的进行：同时细胞内电并进行等长肌张力记录，胆囊平滑肌电-机械耦合;新鲜将使用分散的分离的胆囊肌细胞来测量细胞缩短;细胞溶质钙浓度将使用钙敏感性荧光染料indo-1和细胞膜钙通道将使用全细胞膜片钳来表征法在阐明胆囊收缩机制的过程中，兴奋-收缩偶联，细胞膜电位、钙利用、膜钙电流和胆囊将更好地理解平滑肌收缩。候选人是一位医生兼科学家，他决心开发一种致力于胃肠动力学的研究。实现这一目标，候选人将继续与两个学习受人尊敬的胃肠道平滑肌和心脏基础科学家肌肉生理学与这些研究人员的互动将提供一个激励和富有成效的环境，使候选人能够进行富有成效的研究和定位自己的竞争成功，未来的独立基金。