PHYSIOLOGY OF CHOLINERGIC BASAL FOREBRAIN NEURONS

据报道，许多钙（Ca 2+）依赖性系统会下降， 随着年龄的增长。 受损的Ca 2+稳态最近出现了一个很好的 记录的衰老表现，此外，可能有助于 几种神经退行性疾病，如老年痴呆症。 的精确 参与这种Ca 2+稳态变化的细胞机制尚未发现。 确定了 本提案的目的是描述 基底前脑神经元钙离子调节的变化 在成熟和老化过程中。 这些神经元被选中是因为它们 在记忆和认知中起着关键作用， 几种神经系统疾病的临床症状。 我们将测试 假设存在年龄相关的和细胞特异性的下降， 电压门控钙离子通道（VGCC）在衰老过程中的功能。 这一假设 将通过研究Ca 2+调节的三个关键方面进行测试 包括：a）使用全细胞和单细胞两者通过VGCC的Ca 2+进入; 通道膜片钳记录，B）使用 显微荧光技术，和c）通过神经递质调节VGCC 已知控制电压依赖性Ca 2+运动的系统。 所有这些 参数可以通过对离子门控的直接作用来调节VGCC， 细胞内游离Ca 2+的变化，或涉及信号传导的间接变化 转导和第二信使调节。 实验将 使用Fischer 344大鼠（1月龄、12月龄和20月龄）进行 组）在两个体外制备物中;急性解离的细胞或 在一个薄的脑切片制备中。 薄片制备还将 使我们能够识别胆碱能和非胆碱能神经元， 双标记技术。 许多与年龄有关的缺陷已被证明是部分，如果不是 通过恢复适当的细胞Ca 2+水平完全逆转，或 通量，表明对神经元Ca 2+调节的控制是合理的， 治疗潜力 这些实验的结果不仅 提供与年龄有关的控制的新的定量信息， 神经元Ca 2+稳态，但更重要的是，提供方向， 未来的治疗方法

A number of calcium (Ca2+)-dependent systems have been reported to decline with aging. Impaired Ca2+ homeostasis has recently emerged as a well documented manifestation of aging and, in addition, may contribute to several neurodegenerative disorders such as senile dementia. The precise cellular mechanisms involved in this change in Ca2+ homeostasis have not been determined. The purpose of this proposal will be to characterize changes in Ca2+ ion regulation in identified neurons of the basal forebrain during maturation and aging. These neurons were chosen because they play a pivotal role in memory and cognition as well as having relevance to the clinical symptoms of several neurological disorders. We will test the hypothesis that there is an age-related and cell-specific decline in voltage-gated Ca2+ channel (VGCC) function during aging. This hypothesis will be tested by investigating three key aspects of Ca2+ regulation including; a) Ca2+ entry through VGCC using both whole-cell and single- channel patch-clamp recordings, b) free cytosolic Ca2+ concentrations using microfluorometric techniques, and c) regulation of VGCC by neurotransmitter systems known to control voltage-dependent Ca2+ movement. All of these parameters could regulate VGCCs through direct actions on ion gating, alterations in free cytosolic Ca2+, or indirect changes involving signal transduction and second messenger modulation. Experiments will be performed using Fischer 344 rats (1 month, 12 month and 20 month age groups) in two in vitro preparations; either acutely dissociated cells or in a thin brain slice preparation. The thin slice preparation will also enable us to identify cholinergic versus noncholinergic neurons using double-labelling techniques. Many age-related deficits have been shown to be partially, if not completely, reversed by restoration of appropriate cellular Ca2+ levels or fluxes, suggesting control over neuronal Ca2+ regulation has legitimate therapeutic potential. Results from these experiments will not only provide new quantitative information concerning age-related control of neuronal Ca2+ homeostasis but, more importantly, provide direction for future therapeutic treatments.