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Visual System

開催日 2014/9/12
時間 11:00 - 12:00
会場 Poster / Exhibition(Event Hall B)

Pathway-specific inputs of starburst amacrine cells in the mouse retina

  • P2-133
  • 石井 俊行 / Toshiyuki Ishii:1 金田 誠 / Makoto Kaneda:1 
  • 1:日本医科大学 / Nippon Medical School 

Starburst amacrine cells (SACs) play a pivotal role for the formation of direction selectivity, which have been an attractive target for the study of neural computation. Signal processing in SACs proceeds in parallel through two distinct channels at the inner plexiform layer: signals of ON-SACs are processed in sublamina b, while those of OFF-SACs are integrated in sublamina a. Since an anatomical location of ON-SACs' soma was favorable for electrophysiological recordings in whole mount retina, physiological properties of ON-SACs were used to speculate those of OFF-SACs. In the present study, we introduced slice-patch technique to examine physiological properties of OFF-SACs and directly compared the ligand-gated receptors between ON- and OFF-SACs in the mouse retina. We found that ON- and OFF-SACs used different ligand-gated receptors for signal processing. Purinergic receptors mainly worked in OFF-SACs, while glycinergic receptors mainly functioned in ON-SACs. Glutamatergic receptors distributed equally in both ON- and OFF-SACs. Purinergic inputs in OFF-SACs were mediated by P2X2-purinoceptors and glycinergic inputs in ON-SACs were mediated by strychnine-sensitive glycine receptors. Glutamatergic inputs were mediated through AMPA/KA and NMDA receptors. Moreover, we also demonstrate that purinoceptors modulate the firing activity of ganglion cells in a pathway-specific manner. The retina can adjust the dynamic range of ON- and OFF-pathways to suitable level in various light environments. The presence of pathway-specific inputs to SACs would favor for the distinct adjustment of ganglion cell activity, which might be controlled by ACh and GABA released from SACs, to achieve the best visual acuity in the mouse retina.

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