Si4+ and Chalcedony Precipitation During Oxidative Stress in Rajidae Electrocyte: a mineralogical study.

PRADO FIGUEROA M , BARRERA F , CESARETTI N

Pinamar

Congreso; 41 st Annual Meeting XLI Reunión Anual -Argentine Society for Biochemistry and Molecular Biology- -Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2005

Sociedad Argentina de Neurociencias

At the evidence of the accumulation of Oxygen, Al 3+ and Si2+ in Rajidae electrocyte by X-ray microanalysis it was decided to explorer the presence of Si minerals by a transmitted light petrographic microscope. Fish from San Antonio Oeste, Río Negro Province, were used because electrocyte Si2+ peaks are more important than the same peaks present in fish from Bahía Blanca Estuary. Electric organ cryostat sections of 8 μm of Psammobatis extenta, were performed along its antero-posterior axis, fixed for 15 min at 4°C in 3.7% formaldehyde in 0.1 M PBS, pH 7.2, then washed with PBS and mounted with PBS/glicerol (1:1). It was observed chalcedony distributed in the electrocyte cytoplasm. Chalcedony is a typical mineral present in fossilization process in different organic matter from a wide geological record. Relationship between pH and the solubilities of calcite, quartz, and amorphous silica is well known. High hydrogen ion concentration cause precipitation of SiO2. This observation support the idea of an important role of SiO2 accumulation and pH, in electrocyte fossil formation. In Alzheimer´s disease (AD) and in Rajidae electrocyte, cholinergic innervation are affected.