期刊
VISUAL NEUROSCIENCE
卷 24, 期 3, 页码 333-344出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0952523807070319
关键词
gap junctions; horizontal cells; dopamine receptors; circadian rhythm; rod pathway
资金
- NEI NIH HHS [EY005102] Funding Source: Medline
Horizontal cells are second order neurons that receive direct synaptic input from photoreceptors. In teleosts horizontal cells can be divided into two categories, cone-connected and rod-connected. Although the anatomy and physiology of fish cone horizontal cells have been extensively investigated, less is known about rod horizontal cells. This study was undertaken to determine whether light and/or the circadian clock regulate gap junctional coupling between goldfish rod horizontal cells. We used fine-tipped, microelectrode intracellular recording to monitor rod horizontal cells under various visual stimulation conditions, and tracer (biocytin) iontophoresis to visualize their morphology and evaluate the extent of coupling. Under dark-adapted conditions, rod horizontal cells were extensively coupled to cells of like-type (homologous coupling) with an average of similar to 120 cells coupled. Under these conditions. no differences were observed between day, night, the subjective day, and subjective night. In addition, under dark-adapted conditions, application of the dopamine D(2)-like agonist quinpirole (1 mu M), the D(2)-Iike antagonist spiperone (10 mu M), or the D(1)-like antagonist SCH23390 (10 mu M) had no effect on rod horizontal cell tracer coupling. In contrast, the extent of tracer coupling was reduced by similar to 90% following repetitive light (photopic range) stimulation of the retina or application of the D(1)-agonist SKF38393 (10 mu M) during the subjective day and night. We conclude that similarly to cone horizontal cells, rod horizontal cells are extensively coupled to one another in darkness and that the extent of coupling is dramatically reduced by bright light stimulation or dopamine D(1)-receptor activation. However. in contrast to cone horizontal cells whose light responses are under the control of the retinal clock, the light responses of rod horizontal cells under dark-adapted conditions were similar during the day. night. subjective day, and subjective night thus demonstrating that they are not under the influence of the circadian clock.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据