Proportions of ON-center versus OFF-center cells in retinal ganglion cells with regenerated axons of adult cats.
Axons of retinal ganglion cells (RGCs) of adult cats were transected and regenerated by the transplantation of peripheral nerves. Two months after transplantation dendritic arbors of RGCs with regenerated axons (r-RGCs) were visualized with intracellular injections of horseradish peroxidase (HRP). The HRP-filled r-RGCs were classified as alpha, beta, gamma, or unclassified cells. The r-RGCs were then sectioned vertically and their dendritic ramification in the inner plexiform layer (IPL) was examined to distinguish them as OFF- or ON-center cells. Seventy-nine cells extended their dendrites into either sublamina a (OFF) or sublamina b (ON) of the IPL. Two gamma cells spread dendrites into both ON and OFF sublaminae. The numbers of ON-center cells were greater than those of OFF-center cells in three classes: 22 of 24 beta cells, 4 of 6 gamma cells, and 16 of 18 unclassified cells. These data confirmed the predominance of ON-center cells among X/beta and W cells in previous physiological recordings from regenerated axons of r-RGCs. However, only 4 cells were ON-center among 33 r-RGCs with alpha cell morphology. The result apparently conflicts with the predominance of ON-center Y cells in physiological sampling. Possible explanations for the apparent discrepancy are discussed.
Watanabe
M
M
Department of Physiology, Institute for Developmental Research, Kasugai, Japan.
Fukuda
Y
Y
D000818:Animals; D001369:Axons / Q000502:physiology*; D002415:Cats; D002452:Cell Count; D009416:Nerve Regeneration / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000502:physiology*