title: Loss of calretinin immunoreactive fibers in subcortical visual recipient structures of the RCS dystrophic rat.
abstract: The retinae of dystrophic Royal College of Surgeons (RCS) rats exhibit progressive photoreceptor degeneration accompanied by pathology of ganglion cells. To date, little work has examined the consequences of retinal degeneration for central visual structures in dystrophic rats. Here, we use immunohistochemistry for calretinin (CR) to label retinal afferents in the superior colliculus (SC), lateral geniculate nucleus, and olivary pretectal nucleus of RCS rats aged between 2 and 26 months of age. Early indications of fiber loss in the medial dystrophic SC were apparent between 9 and 13 months. Quantitative methods reveal a significant reduction in the level of CR immunoreactivity in visual layers of the medial dystrophic SC at 13 months (P < 0.02). In dystrophic animals aged 19-26 months the loss of CR fibers in SC was dramatic, with well-defined patches of fiber degeneration predominating in medial aspects of the structure. This fiber degeneration in SC was accompanied by increased detection of cells immunoreactive for CR. In several animals, regions of fiber loss were also found to contain strongly parvalbumin-immunoreactive cells. Loss of CR fibers was also observed in the lateral geniculate nucleus and olivary pretectal nucleus. Patterns of fiber loss in the dystrophic SC compliment reports of ganglion cell degeneration in these animals and the response of collicular neurons to degeneration is discussed in terms of plasticity of the dystrophic visual system and properties of calcium binding proteins.
authors.affiliation: Department of Cell Biology, Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL, London, UK. a.vugler@ucl.ac.uk
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Vugler
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Coffey
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D064032:Calbindin 2; D018450:Disease Progression; D005260:Female; D005829:Geniculate Bodies / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D009137:Muscular Dystrophy, Animal / Q000378:metabolism / Q000473:pathology*; D009412:Nerve Fibers / Q000378:metabolism / Q000502:physiology*; D009847:Olivary Nucleus / Q000473:pathology*; D010320:Parvalbumins / Q000378:metabolism; D051381:Rats; D012162:Retinal Degeneration / Q000473:pathology; D064030:S100 Calcium Binding Protein G / Q000502:physiology*; D013477:Superior Colliculi / Q000473:pathology*
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G