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Excitatory amino acids interfere with normal eye growth in posthatch chick
M Barrington1, J Sattayasai, J Zappia
1Department of Anatomy, Monash University, Clayton, Victoria, Australia.
Current Eye Research
|August 1, 1989
Summary
Excitotoxic amino acids like kainic acid, quisqualic acid, and N-methyl-D,L-aspartate differentially affect chick eye growth and retinal cell morphology. These neurotoxins impact eye size and retinal pathology, suggesting photoreceptors may control eye development.
Area of Science:
- Ophthalmology
- Neuroscience
- Developmental Biology
Background:
- Excitotoxic amino acids are implicated in neuronal damage.
- Understanding their role in ocular development is crucial.
Purpose of the Study:
- To investigate the differential effects of kainic acid, quisqualic acid, and N-methyl-D,L-aspartate on eye growth and retinal morphology in chicks.
- To correlate specific retinal pathologies with observed changes in ocular dimensions.
Main Methods:
- Day-old chicks received intraocular injections of kainic acid, quisqualic acid, or N-methyl-D,L-aspartate.
- Eyeball weight, axial length, equatorial length, anterior chamber depth, and corneal diameter were measured after 7, 14, and 21 days.
- Retinal morphology was examined to identify specific cell damage.
Main Results:
- Kainic acid increased eye weight and equatorial length.
- Quisqualic acid and N-methyl-D,L-aspartate increased anterior chamber depth, with quisqualic acid having a more pronounced effect.
- Kainic acid damaged amacrine, bipolar, ganglion, and photoreceptor cells; quisqualic acid affected amacrine, horizontal cells, and photoreceptors; N-methyl-D,L-aspartate primarily damaged amacrine cells.
Conclusions:
- Different excitotoxins induce distinct patterns of eye growth and retinal pathology.
- The observed changes in eye size are sustained and evident by day 7.
- Photoreceptors are proposed to play a significant role in regulating eye growth.