GABAERGIC MECHANISMS OF THE DISTAL RETINA

有令人信服的证据表明，特定类别的视网膜 水平细胞利用抑制性氨基酸GABA作为 神经递质，而GABA在建立神经递质中起着关键作用。 以感受野为特征的中心-周围对抗 视网膜神经元的特性。 载体介导的GABA转运 水平细胞似乎是该过程的重要组成部分， 也许在吸收和释放 神经传递素 全细胞记录方法的出现 允许这种运输过程以前所未有的方式进行检查 详细使用电生理技术。 描述的实验 在这项建议中，旨在利用这些技术来检查 视网膜水平细胞转运GABA的潜在机制， 并包括对负责摄取的离子机制的研究， 运输的药理学性质，以及 通过神经调节剂多巴胺运输。 的问题 载体介导的GABA从水平细胞流出是产电的 也将被探索。 最后，研究了GABA对视杆细胞的影响。 将检查光感受器和视杆双极细胞， 识别作为GABA突触后靶点的细胞 由水平细胞释放。 这项研究将提供一个更大的 了解GABA在形成中的作用 包围着视觉神经元的感受野。

There is compelling evidence to suggest that specific classes of retinal horizontal cells utilize the inhibitory amino acid GABA as a neurotransmitter, and that GABA plays a key role in establishing the center-surround antagonism that characterizes the receptive field properties of retinal neurons. Carrier-mediated transport of GABA by horizontal cells appears to be an essential component of this process, and serves perhaps both in the uptake and release of the neurotransmitter. The advent of the whole-cell recording method has permitted such transport processes to be examined in unprecedented detail using electrophysiological techniques. The experiments described in this proposal are designed to utilize such techniques to examine the mechanisms underlying the transport of GABA by retinal horizontal cells, and include a study of the ionic mechanisms responsible for uptake, the pharmacological properties of the transport, and the modulation of transport by the neuromodulator dopamine. The question of whether carrier-mediated efflux of GABA from horizontal cells is electrogenic will also be explored. Finally, the effects of GABA on rod photoreceptors and rod bipolar cells will be examined in order to identify the cells that serve as the postsynaptic target for GABA released by horizontal cells. This research should provide a greater understanding of the role that GABA plays in the formation of the surround portion of the receptive fields of visual neurons.