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Abstract #3378 Published in IGR 4-2
Down-regulation of glutamate-induced conductances of retinal horizontal cells after ganglion cell axotomy
Blanco R; Germain F; Velasco A; Villa PdeLExperimental Eye Research 2002; 75: 209-216
After a complete optic nerve section (ONS), retinal neurons may display retrograde transneuronal modifications in the synaptic structures and functions related to retinal disconnection from the brain. The molecular and physiological basis of these changes is not yet fully understood. Immunoreactivity for calbindin was used to specifically immunolabel the horizontal cells (HC) in order to study any morphological changes in the outer plexiform layer (OPL) after axotomy-induced degeneration of retinal ganglion cells (RGC) in the rabbit retina. Glutamate-gated conductance expressed by HC enzymatically dissociated from the rabbit retina was studied at 12 and 21 days after ONS using the whole-cell voltage-clamp technique. The amplitudes of glutamate-induced currents on HC were significantly reduced three weeks after axotomy. However, no morphological changes within the OPL were detected coincident with the progressive loss of glutamatergic responses; similarly, HC dissociated from the axotomized retinal tissue did not differ in morphology or appearance from control retinas. The main finding in this study is that the HC experiment a retrograde transneuronal down-regulation of their ionotropic glutamate-induced conductance following axotomy-induced degeneration of RGC.
Dr. R. Blanco, Department of Physiology, School of Medicine, University of Alcala, Madrid, Spain
Classification:
1.3 Pathogenesis (Part of: 1 General aspects)
