COMPARISON OF THE EFFECTS OF FLICKERING AND STEADY LIGHT ON DOPAMINE RELEASE AND HORIZONTAL CELL COUPLING IN THE MUDPUPPY RETINA
COMPARISON OF THE EFFECTS OF FLICKERING AND STEADY LIGHT ON DOPAMINE RELEASE AND HORIZONTAL CELL COUPLING IN THE MUDPUPPY RETINA
复制标题
DOI：
10.1152/jn.1992.67.2.364
复制
发表时间：
1992-02-01
影响因子：
2.5
通讯作者：
MCREYNOLDS, JS
中科院分区：
文献类型：
--
作者：
DONG, CJ;MCREYNOLDS, JS
1. 在暗适应的mudpuppy视网膜中，比较了闪烁适应照明（重复闪烁）和稳定适应照明对感受野中心和周围部分水平细胞对照明反应的影响. 暴露于闪烁的适应光引起的幅度增加的反应，在接收场中心的小斑点和减少的反应，以同心圆环。 这被解释为由于水平单元之间的耦合电阻的增加。 闪烁的适应光的解耦合效果不大于相同数量的稳定的适应光在相同的强度，即使当闪烁的速率变化了10.4倍。 闪烁光的解偶联作用被多巴胺拮抗剂氟奋乃静和SCH 23390阻断，表明它是由多巴胺释放介导的. 2-氨基-4-膦酰基丁酸酯（APB）的存在也阻断了闪烁光的解偶联效应，这阻止了中心双极细胞的光反应，但不阻止偏离中心双极细胞的光反应，表明闪烁光通过中心通路增加多巴胺的释放。 γ-氨基丁酸（GABA）拮抗剂荷包牡丹碱具有类似于适应光照的解偶联作用。 这种作用被多巴胺拮抗剂阻断，表明在泥小狗视网膜中存在与先前在鱼类和海龟视网膜中报道的类似的多巴胺释放的强直性GABA介导的抑制。 荷包牡丹碱的解偶联作用不被APB逆转。 然而，APB单独引起的耦合，这是迅速逆转荷包牡丹碱增加。 这表明APB对水平细胞偶联的影响不是由于APB对多巴胺释放细胞的直接作用。 结果表明，闪烁光通过与先前针对稳定光所示相同的机制（增加多巴胺的释放）和途径（通过中心双极细胞）影响水平细胞耦合。 虽然闪烁光的这种效应的大小可能取决于闪烁光刺激的参数，但没有证据表明其对水平细胞的解偶联作用涉及单独的途径或发射机制。
1. The effects of flickering adapting illumination (repetitive flashes) on horizontal cell responses to illumination of the center and surround portions of the receptive field were compared with those of steady adapting illumination in dark-adapted mudpuppy retinas.2. Exposure to flickering adapting light caused an increase in amplitude of responses to small spots in the receptive-field center and a decrease in the response to a concentric annulus. This is interpreted as due to an increase in coupling resistance between horizontal cells.3. The uncoupling effect of flickering adapting light was no greater than that of the same quantity of steady adapting light at the same intensity, even when the rate of flickering was varied by a factor of 10.4. The uncoupling effect of flickering light was blocked by the dopamine antagonists fluphenazine and SCH23390, indicating that it is mediated by dopamine release.5. The uncoupling effect of flickering light was also blocked in the presence of 2-amino-4-phosphonobutyrate (APB), which prevents light responses of on-center but not off-center bipolar cells, suggesting that flickering light increases dopamine release via the on-pathway.6. The gamma-aminobutyric acid (GABA) antagonist bicuculline had an uncoupling effect similar to that of adapting illumination. This effect was blocked by dopamine antagonists, indicating that there is tonic GABA-mediated inhibition of dopamine release in mudpuppy retina similar to that previously reported by others in fish and turtle retinas.7. The uncoupling effect of bicuculline was not reversed by APB. However, APB alone caused an increase in coupling that was rapidly reversed by bicuculline. This indicates that the effect of APB on horizontal cell coupling was not due to a direct action of APB on dopamine-releasing cells.8. The results indicate that flickering light affects horizontal cell coupling via the same mechanism (increased release of dopamine) and pathway (via on-center bipolar cells) as shown previously for steady light. Although the magnitude of this effect of flickering light may depend on the parameters of the flickering light stimulus, there is no evidence that its uncoupling action on horizontal cells involves a separate pathway or transmitter mechanism.