HIPPOCAMPAL INTERNEURONS--IN CULTURE AND IN SLICES

描述：调节神经递质释放到突触 间隙是中枢神经系统实现突触可塑性的主要手段， 神经系统 由于钙离子通过电压依赖性 通道是必要的神经递质释放，调制的 神经递质对这些通道的活动可能是一种常见的 调节突触强度的机制。 PI中的项目 实验室利用海马体中特征鲜明的回路 研究钙通道的功能和特性 控制特定抑制性突触的释放， 通过神经递质调节这些通道。 海马体是 参与记忆形成和癫痫发作。 的抑制 尤其是海马体的回路， 控制癫痫形成。 本文中概述的实验 建议将为未来的自然研究提供坚实的基础 突触传递 第一个具体目标是优化 培养和全细胞记录条件对海马抑制 中间神经元，以便在培养中获得与 在年龄匹配的海马切片中可见。 将从以下组织中获取组织： 不同年龄的动物，并允许在培养中保持各种 次 这些实验是未来所有 实验在这个提议中。 第二个具体目标是 确定识别抑制性中间神经元的可行性， 使用全细胞贴片的基于电生理参数的培养 在电流箝位模式下进行箝位记录。 这些研究报告将 与年龄匹配的相同实验平行进行 海马切片。 这些实验的结果将验证 培养海马细胞用于中间神经元研究 行为和功能。 第三个具体目标是提供第一个 彻底表征的电压依赖性钙通道， 3种不同抑制性突触的突触前细胞 海马全细胞电压钳记录 细胞 在这些实验中获得的数据将提供基础 为将来研究神经递质的释放和钙的调节 渠道 方向层/肺泡的垂直细胞，篮状细胞， 细胞层中的细胞和星状细胞层中的细胞 将研究腔隙/分子。 垂直细胞和篮状细胞 介导前馈和复发性抑制，主要通过 激活GABAA受体。 星状细胞介导前馈 通过激活GABAB受体抑制。 PI的未来研究 实验室将致力于了解神经递质如何调节 通过调节不同的钙通道类型的特异性突触 提供了对突触可塑性的一些机制的深入了解。 此外，这些研究将为以下方面提供更好的基础： 药物治疗的疾病，如癫痫和 神经变性，其中神经调节剂的使用被积极地 追求。 此外，这些信息还将提供有关 各种人类神经元疾病的细胞病理学，其中突触 功能被改变了。

DESCRIPTION: Regulation of neurotransmitter release into the synaptic cleft is a primary means of achieving synaptic plasticity in the central nervous system. Since influx of calcium through voltage-dependent channels is necessary for neurotransmitter release, modulation of the activity of these channels by neurotransmitters is likely to be a common mechanism of regulating synaptic strength. The projects in the PI's laboratory exploit the well-characterized circuitry of the hippocampus to investigate the function and identity of the calcium channels controlling release in specific inhibitory synapses, and also the modulation of these channels by neurotransmitters. The hippocampus is involved in both memory formation and epileptic seizures. The inhibitory circuitry of the hippocampus, in particular, is extremely important in the control of seizure formation. The experiments outlined in this proposal will provide a solid foundation for future studies on the nature of synaptic transmission. The first specific aim is to optimize the culturing and whole cell recording conditions for hippocampal inhibitory interneurons, in order to obtain comparable excitability in culture as is seen in age-matched hippocampal slices. Tissue will be obtained from animals of various ages and allowed to remain in culture for various times. These experiments are a prerequisite for all the future experiments featured in this proposal. The second specific aim is to determine the feasibility of identifying inhibitory interneurons in culture based on electrophysiological parameters using whole cell patch clamp recording in the current clamp mode. These studies will be performed in parallel with identical experiments in age-matched hippocampal slices. The results from these experiments will validate the use of cultured hippocampal cells for studies on interneuron behavior and function. The third specific aim is to provide the first thorough characterization of the voltage dependent calcium channels in the presynaptic cells of 3 different inhibitory synapses in the hippocampus using whole cell voltage clamp recording in dissociated cells. The data obtained in these experiments will provide a foundation for future studies on neurotransmitter release and modulation of calcium channels. The vertical cells of the stratum oriens/alveus, the basket cells in the stratum pyramidale, and stellate cells in the stratum lacunosum/moleculare will be studied. The vertical and basket cells mediate both feedforward and recurrent inhibition primarily by activation of GABAA receptors. The stellate cells mediate feedforward inhibition by activation of GABAB receptors. Future studies in the PI's laboratory will be aimed at understanding how neurotransmitters regulate specific synapses by modulation of distinct calcium channel types providing insight into some of the mechanisms of synaptic plasticity. In addition, these studies will provide a better foundation for pharmaceutical therapies in diseases such a epilepsy and neurodegeneration where the use of neuromodulators is being actively pursued. Moreover, this information will also provide insights into the cellular pathology of various human neuronal disorders in which synaptic function is altered.