Neurofibrillary tangles and Al3+ accumulation in Rajidae electric organ: an X-ray microanalysis.

BARRERA F, FLORES VALERIO WLA, PRADO FIGUEROA M

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. An association between the presence of Al3+, Si2+ and Alzheimer's disease (AD) has been reported. At the evidence of the accumulation of oxygen, Al3+ and Si2+ in Rajidae electrocyte by X-ray microanalysis, it was decided to explorer the presence of neurofibrillary tangles (NFT´s). Psammobatis extenta is an electrical fish from Rajidae family. According to their semicircle electrocyte shape, they are the less derived of this family. Electric organ cryostat sections of 8 μm of P. extenta, were performed along its anteroposterior axis; sections were treated by a modified Bielschowski method. It was observed this lesions, by a light microscope, distributed in the electrocyte cytoplasm. NFT´s have a circular shape and are around of 2-3 μm. In accompanied muscle cells, NFT´s are absent. This observation support the idea of an important role of Al 3+ accumulation and oxidative stress in NFT´s development. In AD and in Rajidae electrocyte, cholinergic innervation are affected. P. extenta electrocyte can be use as an animal model for AD.