MICROCRYSTALLINE FLUORESCENT VARIETY OF AQUARTZ (SIO2) IN ELECTRIC ORGANS OF Psammobatis extenta (GARMAN, 1913) (BATOIDEA: RAJIDAE).

BARRERA F; PRADO FIGUEROA M.

INTERNATIONAL JOURNAL OF MORPHOLOGY

Sociedad Chilena de Anatomía

Lugar: Temuco; Año: 2008 vol. 26 p. 763 - 763

0717-9367

The electric organs (EO) of Psammobatis extenta produce weak electrical discharges to the surrounding environment. Its majority cells -electrocytes- derived from myoblasts have evolved and differential independently, losing the contractile ability. In previous works we employed EDS-SEM and documented the presence of aluminium and silicon in significant concentrations. Zinc, oxigen and cupper were also localized. For Polarized Light Microscopy we could also identify specifically a microcrystalline variety of SiO2: chalcedony. Probably it would be coming towards the nervous terminals cholinergics in a semi-fluid form supersaturated in silicon and to precipitate towards the crystalline form due to the changes of pH and Eh (potential of oxidation) generated in the electrocytes. Now, using Epifluorescence Microscopy (Epi-fl) and Confocal Laser Scanning Microscopy (LCSM) on EO subcellular extracts of P. extenta obtained for differential centrifugation we identify that the calcedonia autofluorescent is distributed in all the subcellular fractions. Neuronal cell death and synaptic terminal degeneration have been noted in the EO of this fishes (Fox et al., 1990 and our observations). The crystalline form of this mineral of quartz could interact with the DNA of the nucleus of the electrocyte and to intervene in processes of cellular death since it has been suggested for other cellular types. There is this the first time that is demonstrated the presence of the autofluorescent chalcedony in EO using Epi-fl and LCSM.