M1 intrinsically photosensitive Retinal Ganglion Cells regulate light adaptation through dopamine amacrine cells by intra-retinal axon collateral
| Autor: | Nan-Fu Liou, 劉南甫 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 Ambient luminance is a vital environmental information for us to maintain our normal physiological function, but its contribution to our visual system is still poorly understood. It has been shown that our visual system primary detect contrast, while the background luminance plays little to no role for pattern forming functions. However, recent evidence has suggested that environment luminance may be involved in vision through intrinsic photosensitive retina ganglion cell (ipRGC), which is the third type of photoreceptor in mouse retina. ipRGCs express melanopsin for light sensing and transmit their signal directly to the brain for circadian photo-entrainment, pupillary light reflex and sleep regulation. Previous studies showed that ipRGCs can be divided into at least five types according to their dendritic morphology and cell body size. Furthermore, recent study showed that M1 type ipRGCs have intra retinal axons collateral innervating retrogradely to the inner plexiform layer (IPL), which could form a putative synapse with dopamine amacrine cells (DACs). Since dopamine is important for the light adaptation, we hypothesize that the M1 ipRGCs may also be involved in visual function through the connection with DACs. Using genetic mouse model and electroretinogram, our study shows that elimination of ipRGCs blocks the light adaptation of cones, while application of D1 or D4 receptor agonist can rescue the light adaptation. Together, our data indicates that ipRGCs could modulate visual function through DACs and probably be involved in higher complicated visual function. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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