Identification and morphological classification of neuronal cell types within Astyanax mexicanus retina

Photoreceptor, bipolar and amacrine cells in the retina of surface fish Astyanax mexicanus were morphologically characterized using DiOlistic techniques. In this method, DiI-coated microcarriers are applied at high speed onto the surfaces of retinal slices where DiI then delineates axons, somata and dendrites of isolated neurons. Three photoreceptors were identified: rods, single and double cones. Bipolar cells were separated into eleven morphological types: three Boff-types with axon boutons exclusively in sublamina a, four-Bon types with axon boutons exclusively in sublamina b and four multistratified types with axon boutons in both sublamina a and b. Amacrine cells were separated into thirteen morphological types: seven Aoff-types and six-Aon types. The information from this study can be used to compare the overall eye development and general changes in retinal structure, degrees of retinal degeneration and/or apoptotic loss of specific cell types between the ancestral Astyanax morphotype and the regressed cave forms.