RECEPTOR-MEDIATED CALCIUM ENTRY IN ACINAR CELLS

受体介导的腺泡细胞钙离子内流 钙（Ca 2+）是将细胞刺激耦合到 腺泡细胞分泌。 细胞刺激会导致 细胞内Ca 2+浓度（[Ca 2 +]i），当Ca 2+从 通过可溶性第二信使的作用来调节细胞内储存。 这 释放导致细胞内Ca 2+储存的耗尽。 受体- 介导的钙离子进入（RMCE）是一个过程， 独立于膜电位介导钙进入。 RCME是 在分泌细胞中激动剂刺激后观察到，并且是必需的， “补充”钙储存和恢复细胞反应。 一部分 分泌细胞中的RMCE已被证明依赖于 细胞内钙储存的“空虚”，在此将被称为 消耗激活的钙进入。 该项目的长期目标是 描述消耗激活的钙进入的机制， 细胞内的信使或机制，负责其 调控 关于消耗激活钙机制的详细信息 进入或其监管仍然未知。 候选人的初选 实验已经表明：a）消耗激活的钙进入可以是 使用膜片钳技术在Ca 2+耗尽的腺泡细胞中测量， FURA-2荧光，B）硝普钠，其提高细胞内循环 喹核苷-3，5-单磷酸可增强钙内流。 具体 研究的目的是：a）确定消耗的调节- 通过确定环核苷酸或其他 信使起调节钙进入的作用，和B）确定是否 消耗激活的钙进入由第二信使操作的 Ca 2+通道或通过另一种机制如离子交换剂;这些 实验将使用膜片钳记录FURA-2荧光 测量. 对方法的适用性和可行性进行了验证 在初步研究中得到证实。 这些初步研究提供了 这些证据表明，拟议的实验将产生有用的结果。 GRANT-R01NS23077 癫痫是一种主要的中枢神经系统衰弱性疾病 其特征在于大脑的异常电活动。 这 疾病影响着数百万人的生活。 虽然癫痫可以 在许多情况下用药物治疗，相当多的患者 是药物治疗难以治愈的 这项研究计划的目的是 确定人类癫痫的细胞机制，以协助 在开发更好的治疗糖尿病的方法方面。 蜂窝 癫痫发作活动的机制将通过研究 颞叶齿状回的电活动 癫痫患者 齿状回在大脑皮层中占有重要的位置， 控制海马体中的电事件，海马体是大脑皮层的一个重要部位， 癫痫发作开始。 齿状回神经元的电活动 将在颞叶癫痫患者的脑切片中检查脑回 患者 兴奋性和抑制性突触的相对影响 输入和内在膜特性对超兴奋性的影响 检查齿状回。 纵向梯度假说 齿状回的过度兴奋（癫痫发作敏感性）将是 通过在沿着的几个位置进行生理记录进行测试， 齿状回 对这些生理观察的解释 将通过组织学评估（突触重组和 细胞损失）。 结果从拟议的 实验将提供非常需要的信息， 癫痫的生理基础

Receptor Mediated Calcium Entry in Acinar Cells Calcium (Ca2+) is the final messenger coupling cellular stimulation to secretion in acinar cells. Cellular stimulation causes a rise in intracellular Ca2+ concentration ([Ca2+]i) when Ca2+ is released from intracellular stores via the action of soluble second messengers. This release results in the depletion of intracellular Ca2+ stores. Receptor- mediated calcium entry (RMCE) is a process whereby receptor activation mediates calcium entry independently of membrane potential. RCME is observed after agonist stimulation in secretory cells, and is necessary to "refill" calcium stores and to restore cellular responsiveness. A portion of RMCE in secretory cells has been shown to be dependent on the "emptiness" of intracellular calcium stores and will be refereed to here as depletion-activated calcium entry. The long-range goal of this project is to describe the mechanism of depletion-activated calcium entry and the intracellular messengers or mechanisms that are responsible for its regulation. Details about the mechanism of depletion-activated calcium entry, or its regulation, remain unknown. The candidate's preliminary experiments have shown that: a) Depletion-activated calcium entry can be measured in Ca2+ depleted acinar cells using the patch-clamp technique and FURA-2 fluorescence, b) nitroprusside, which raises intracellular cyclic quanosine-3,5-monophosphate, can potentiate calcium entry. The specific aims of the research are: a) to define the regulation of depletion- activated calcium entry by determining how cyclic nucleotides or other messengers act to modulate calcium entry, and b) to determine whether depletion-activated calcium entry is carried by a second messenger-operated Ca2+ channel or by another mechanism such as an ion exchanger; these experiments will use both patch-clamp recording a FURA-2 fluorescence measurements. The suitability and feasibility of the methods have been demonstrated in the preliminary studies. These preliminary studies provide evidence that the proposed experiments will yield useful results. GRANT-R01NS23077 Epilepsy is a major debilitating disorder of the central nervous system which is characterized by abnormal electrical activity of the brain. This disease affects the lives of millions of people. Although epilepsy can be treated in many cases with drug therapy, a significant number of patients are intractable to drug treatment. The aim of this research plan is to determine the cellular mechanisms of epilepsy in humans, in order to assist in developing improved treatments for seizure-disorders. The cellular mechanisms of seizure activity will be investigated by studying the electrical activity which occurs in the dentate gyrus of temporal lobe epileptic patients. The dentate gyrus holds a crucial position in the control of electrical events in the hippocampus, an important site of seizure initiation. The electrical activity of neurons in the dentate gyrus will be examined in brain slices from temporal lobe epileptic patients. The relative influences of excitatory and inhibitory synaptic input, and intrinsic membrane properties on hyperexcitability of the dentate gyrus will be examined. The hypothesis of a longitudinal gradient in hyperexcitability (seizure susceptibility) of the dentate gyrus will be tested by performing physiological recordings at several locations along the dentate gyrus. The interpretation of these physiological observations will be assisted by histological assessment (synaptic reorganization and cell loss) of tissue from the same regions. The results from the proposed experiments will provide greatly needed information concerning the physiological basis of seizure disorders.