THE STRUCTURE OF MITOCHONDRIA IN ROD AND CONE PHOTORECEPTORS

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 我们的研究的首要目标是发展一个全面的结构和功能的理解杆小球和锥椎弓根带状突触终端。脊椎动物光感受器是非尖峰神经元，其在黑暗中维持带状突触的持续去极化和神经递质释放，并产生光依赖性分级超极化反应。在常规神经元中，Ca 2+在动作电位期间进入突触前末梢，其局部浓度增加触发瞬时胞吐。与此相反，脊椎动物的光感受器是nonspiking神经元，保持持续的去极化和神经递质释放从带状突触在黑暗中，并产生光依赖性的分级超极化反应。杆状细胞以高保真度传输单光子响应，而锥细胞则不太敏感，并表现出更快的响应动力学。这些差异可能是由于突触前Ca 2+动力学的变化。线粒体、内质网（ER）、质膜Ca ~（2+）ATP酶（PMCA）和Na ~+-Ca ~（2+）交换器（NCX）之间的代谢偶联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ATP和Ca 2+动态杆小球和锥椎弓根的时空调节。

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.