Histochemical demonstration of glycogen in neurons of the cat retina.
OBJECTIVE
To demonstrate histochemically the cellular distribution of particulate glycogen in the cat retina and to correlate it with glucose sensitivity of neuronal electrical activities.


METHODS
Free-floating, ultrathin sections of cat eyes (without glucose challenges) were stained by the periodic acid-thiocarbohydrazide-silver proteinate procedure and examined by electron microscopy.


RESULTS
Muller cells were filled uniformly with fine-grain glycogen throughout all retinal layers. Particle density was higher in Muller cells of the peripheral retina than in those of central retina. Astrocytes contained little, if any, particulate glycogen. Alpha and beta ganglion cells had a heavy content of clumped glycogen granules. Rod bipolar and A17 amacrine cells of the rod pathway were stained intensely with particulate glycogen. No glycogen was seen in photoreceptor cells, cone bipolar cells, and the majority of amacrine cells, including AII cells of the rod pathway. However, one type of cone bipolar-driven amacrine cell was intensely glycogen positive. Its ultrastructural morphology, stratification pattern, and synaptology suggest that is a wide-field, axon-bearing type called A22.


CONCLUSIONS
Except for the cone bipolar-driven ON-OFF A22 amacrine cell, it appears that glycogen staining preferentially labels neurons of the rod pathway. These observations are compatible with the reported sensitivity of the rod-driven electroretinogram and optic nerve response to glucose in the cat retina.
Rungger-Brändle
E
E
Department of Ophthalmology, University Hospital, Geneva, Switzerland.
Kolb
H
H
Niemeyer
G
G
D000818:Animals; D001253:Astrocytes / Q000737:chemistry / Q000648:ultrastructure; D002415:Cats; D004596:Electroretinography; D005947:Glucose / Q000494:pharmacology; D006003:Glycogen / Q000032:analysis* / Q000648:ultrastructure; D006651:Histocytochemistry / Q000379:methods; D009474:Neurons / Q000737:chemistry* / Q000648:ultrastructure; D012160:Retina / Q000737:chemistry* / Q000648:ultrastructure; D017949:Retinal Cone Photoreceptor Cells / Q000737:chemistry / Q000648:ultrastructure; D012165:Retinal Ganglion Cells / Q000737:chemistry / Q000648:ultrastructure; D017948:Retinal Rod Photoreceptor Cells / Q000737:chemistry / Q000648:ultrastructure
D006003:Glycogen; D005947:Glucose