THE STRUCTURE OF MITOCHONDRIA IN ROD AND CONE PHOTORECEPTORS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们研究的主要目标是对视杆、球体和锥体蒂突触终末的结构和功能有一个全面的了解。脊椎动物光感受器是一种非尖峰神经元，在黑暗中维持带状突触的持续去极化和神经递质释放，并产生光依赖的分级超极化反应。在常规神经元中，钙离子在动作电位的作用下进入突触前终末，其局部浓度的增加会触发一过性的胞吐。相比之下，脊椎动物的光感受器是非尖峰神经元，在黑暗中维持带状突触的持续去极化和神经递质释放，并产生光依赖的分级超极化反应。杆可以高保真地传输单光子响应，而锥体则不那么灵敏，表现出更快的响应动力学。这些差异可能是由于突触前钙动态的变化所致。线粒体、内质网(ER)、质膜Ca~(2+)-ATPase(PMCA)和Na~+-Ca~(2+)交换器(NCX)之间的代谢耦合和相互作用协调控制突触前ATP的产生和Ca~(2+)动力学。我们的结构和功能研究的目标是确定杆状球体和锥体蒂中ATP和钙动态的时空调节。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overarching goal of our studies is to develop a comprehensive structural and functional understanding of rod spherule and cone pedicle ribbon synaptic terminals. Vertebrate photoreceptors are nonspiking neurons that maintain sustained depolarization and neurotransmitter release from ribbon synapses in darkness and produce light-dependent graded hyperpolarizing responses. In conventional neurons, Ca2+ enters presynaptic terminals during an action potential and its increased local concentration triggers transient exocytosis. In contrast, vertebrate photoreceptors are nonspiking neurons that maintain sustained depolarization and neurotransmitter release from ribbon synapses in darkness and produce light-dependent graded hyperpolarizing responses. Rods transmit single photon responses with high fidelity, whereas cones are less sensitive and exhibit faster response kinetics. These differences are likely due to variations in presynaptic Ca2+ dynamics. Metabolic coupling and cross-talk between mitochondria, endoplasmic reticulum (ER), plasma membrane Ca2+ ATPase (PMCA), and Na+-Ca2+ exchanger (NCX) coordinately control presynaptic ATP production and Ca2+ dynamics. The goal of our structural and functional studies is to determine the spatiotemporal regulation of ATP and Ca2+ dynamics in rod spherules and cone pedicles.