Metabolic activity in optic tectum during regeneration of retina in adult goldfish

Abstract

Retinal and visual function returns following retinal destruction by ouabain in adult goldfish (Carassius auratus). Although the precise cellular mechanisms are unclear, the ability to regenerate CNS neurons and connections that subsequently sustain visual behavior is remarkable, especially for an adult vertebrate. In this paper, we ask whether visual stimulation via new retinal cells can activate existing cells in the optic tectum, which normally receives the largest retinal projection in this species. The right eyes of adult goldfish were injected with ouabain. After 1-18 weeks the conscious, freely moving fish were exposed to spatially and temporally varying visual stimuli and the resulting tectal metabolic activity was determined with the autoradiographic deoxyglucose method. In normal controls without lesions, visual stimulation produced equally strong metabolic activity in both tectal hemispheres, peaking in the layer where most retinotectal projections terminate (N = 6). One week after ouabain injection, metabolic activity in the contralateral, deprived tectum was dramatically reduced (N = 5), closely resembling the effect of unilateral ocular enucleation (N = 5). However, 9-18 weeks after ouabain injection, metabolic activity in the deprived tectum recovered to a level that was statistically indistinguishable from normal controls (N = 6). These findings suggest that, after a comprehensive cytotoxic lesion of the retina, regenerated ganglion cells not only establish new connections with the preexisting optic tectum, but also effectively transmit visual information they receive from newly generated photoreceptors to the "old" tectum.

Ganglion cell regeneration following whole‐retina destruction in zebrafish

“…In the goldfish, metabolic activity in the visually-deprived optic tectum begins to return 70-100 days after the ouabain treatment (Melzer and Powers, 2001), while the DLR recovers gradually over 50-210 days (Mensinger and Powers, 1999). Recovery of optokinetic nystagmus, a behavior that requires some degree of spatial resolution, has been documented at 99 days after ouabain treatment (Kästner and Wolburg, 1982).…”

Visual behavior of adult goldfish with regenerating retina

“…injection of the metabolic poison ouabaiñ Maier & Wolburg, 1979;Kurz-Isler & Wolburg, 1982;Raymond et al, 1988;Mensinger & Powers, 1999;Melzer & Powers, 2001! injection of the metabolic poison ouabaiñ Maier & Wolburg, 1979;Kurz-Isler & Wolburg, 1982;Raymond et al, 1988;Mensinger & Powers, 1999;Melzer & Powers, 2001!…”

“…The neural retina in adult teleost fish can regenerate after destruction by intraocular~io! injection of the metabolic poison ouabaiñ Maier & Wolburg, 1979;Kurz-Isler & Wolburg, 1982;Raymond et al, 1988;Mensinger & Powers, 1999;Melzer & Powers, 2001! or by surgical retinal lesion~Hitchcock et al, 1992!.…”

Neurogenesis in the Fish Retina

“…These data suggest that the axons of regenerated ganglion cells reach (and pass through) the optic nerve head, but they do so asynchronously. In the goldfish, recovery of functional connections of the optic tract to the tectum has been established through the use of metabolic labeling (Melzer and Powers, 2001).In these experiments, fish were subjected to visual stimuli coincident with systemic administration of [ 3 H]deoxyglucose. This method documented both the loss of metabolic activity in tecta lacking input from a (ouabain-treated) retina, as well as recovery of this activity 80-120 days after the treatment.…”