Topography of horizontal cells in the retina of the domestic cat.
Neurofibrillar methods stain a class of horizontal cells in the cat retina which are shown to be identical with the A-type horizontal cell of Golgi-staining. Thus all of the A-type cells of a single retina can be observed. On this basis the changes in density and dendritic field size of A-type horizontal cells with respect to retinal eccentricity were measured. The decrease in density from centre to periphery is balanced by a corresponding increase in size of the dendritic field. Consequently each retinal point--independent of retinal position--is covered by the dendritic fields of three of four A-type horizontal cells. The nuclei and nucleoli of B-type horizontal cells could also be recognized in neurofibrillar-stained material and thus their distribution was determined. The density ratio B-type: A-type is 2.8 +/- 0.4 and does not vary much from the centre to the periphery of the retina. Each retinal point is also covered by four B-type horizontal cells. Thus a single cone can contact a maximum of eight horizontal cells. The rate of density decrease from centre to periphery is closely similar in cones and horizontal cells but greater in ganglion cells.
D000818:Animals; D002415:Cats / Q000033:anatomy & histology*; D003712:Dendrites / Q000648:ultrastructure; D009454:Neurofibrils / Q000648:ultrastructure; D010786:Photoreceptor Cells / Q000166:cytology; D012160:Retina / Q000166:cytology*; D013194:Staining and Labeling; D014795:Visual Pathways / Q000166:cytology