Tunicamycin-induced degeneration in cone photoreceptors.
Tunicamycin (TM), an inhibitor of dolichylphosphate-mediated protein glycosylation, was injected intravitreally into the eyes of diurnal rodents with cone-dominated retinas. Injection of 1 microgram of the B2 isomer led to a progressive degeneration of the photoreceptor outer segments and disruption of the RPE-photoreceptor interface that took place over a 10-day period. Cone outer segments were shortened by postinjection day 6 and virtually absent by day 9. The microvilli that normally protrude from the apical surface of the retinal pigment epithelium were replaced by a fringe of shortened processes. The other retinal layers showed no morphological evidence of disruption. Retinal sensitivity, as measured by electroretinographic b-wave threshold, showed a significant and progressive decline over the 10-day course of the experiment that paralleled the disruption of retinal morphology. These results suggest that TM leads to similar morphological and electrophysiological effects on rod and cone photoreceptors.
Anderson
D H
DH
IES, Neuroscience Research Program, University of California, Santa Barbara 93106.
Williams
D S
DS
Neitz
J
J
Fariss
R N
RN
Fliesler
S J
SJ
D000818:Animals; D004596:Electroretinography / Q000187:drug effects; D010786:Photoreceptor Cells / Q000187:drug effects* / Q000648:ultrastructure; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000648:ultrastructure; D012162:Retinal Degeneration / Q000139:chemically induced* / Q000473:pathology; D012589:Sciuridae; D014415:Tunicamycin / Q000633:toxicity*; D014822:Vitreous Body / Q000187:drug effects
D014415:Tunicamycin