1986 Fiscal Year Final Research Report Summary
Studies on putative transmitter substances at the inner plexiform layer of the retina.
| Project/Area Number |
59480110
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurophysiology and muscle physiology
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| Research Institution | St. Marianna University School of Medicine |
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Principal Investigator |
TOYODA Jun-ichi St. Marianna Univ. School of Med., 医学部, 教授 (90081629)
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| Co-Investigator(Kenkyū-buntansha) |
KUJIRAOKA Toru ibid., 医学部, 助手 (40130992)
FUJIMOTO Masaaki ibid., 医学部, 講師 (90081728)
冨田 恒男 聖マリアンナ医科大学, 医学部, 客員教授 (80090116)
TOMITA Thuneo St. Marianna Univ. School of Med.
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| Project Period (FY) |
1984 – 1986
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| Keywords | Retina / Bipolar cell / Amacrine cell / Synaptic transmission / Transmitter / Glutamate |
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| Research Abstract |
1. Synaptic transmission from bipolar to amacrine cells: Responses of a bipolar and an amacrine cell were recorded simultaneously. Artificial depolarization of the bipolar cell by current elicited a depolarizaiton in the amacrine cell. The results confirmed the excitatory action of bipolar cell transmitters.
2. Effect of putative transmitters on amacrine cells: Effects of drugs on amacrine cells were tested by applying these drugs iontophoretically near the cells recorded.
3. Drugs having an excitatory action: Aspartate, glutamate and Ach showed a depolarizing effect which was not blocked by cobalt ions. Thus amacrine cells appeared to have receptors for these agents. Though glutamate is one of strong candidates for bipolar transmitter, its release must be verified.
4. Drugs having an inhibitory action: GABA and glycine showed an inhibitory effect on amacrine cells. The effect could be mediated partly through bipolar cells but also directly on amacrine cells.
5. Effect of drugs on retinal spreading depression(SD): SD can be induced by exposing the retina to a high K or low Cl medium. It is suspected that SD is due to the abonormal excitation of the neurons in the inner retina. It may therefor serve as an index for the excitability of ganglion and amacrine cells. Effect of drugs used in the above experiments was also tested on SD. An excitatory action of Ach and an inhibitory action of GABA and glysine were confirmed. But the effect of glutamate was variable. Further experiments are necessary before accepting glutamate as a bipolar cell transmitter.
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Research Products
(11 results)
