Espectral deprivation neuroplastic changes at retinal level

FOSSER, N.S., BENACERRAF, A., RÍOS H.

Huerta Grande Córdoba ARGENTINA

Congreso; Sociedad Argentina de Investigación en Neurociencias ?SAN-. Taller Argentino de neurociencias -TAN-; 2009

Coding of spectral information by the photoreceptors is at least ambiguous.  Spectral information must be recoded in the retina and others postretinal centres in order to achieve a functional meaning.  Light processing requires the comparison of stimulation patterns of at least two spectral channels in order to lead to percepts such as hue, saturation and brightness of colors. Morphometric and densitometric analyses were performed at the level of the first retinal synapse, in the outer plexiform layer and at the second order synapses at the inner plexiform layer.  Animals were divided into four groups, all of them with a 12h light and 12h dark circadian cycle.  For rearing under spectral deprivation, light was generated using high power leds.  One group was exposed to a white cold light, another to red light (592nm), other to green light (520nm) and the last one to blue light (460nm).   After 6, 9 and 12 day the chicks were deeply anesthetized and perfused through the left ventricle. Eyes were dissected out, postfixed and retinas were cut and immunolabeled mainly to detect calbindin, calretinin and SV2 as well as others markers.                 Our preliminary results showed that retinas from animals reared with red, green or blue light have smaller synaptic pedicle than animals reared in white light.  We also found differences in the cone outer segment lengths, related with the sensitivity of the cells. The IPL pattern of expression of some proteins reveals that spectral deprivation affects not only the first synaptic level.  In summary, we have shown developmental plasticity in the color vision system of the chick retina.  UBACyT O014