Article

Cellular and Molecular Neurobiology

, Volume 4, Issue 2, pp 125-142

First online:

The electric organ ofDiscopyge tschudii: Its innervated face and the biology of acetylcholinesterase

  • Bernardita MéndezAffiliated withLaboratory of Neurophysiology, Faculty of Biological Sciences, Catholic University of Chile
  • , Jorge GarridoAffiliated withLaboratory of Histology, Faculty of Biological Sciences, Catholic University of Chile
  • , Mafalda MaldonadoAffiliated withLaboratory of Neurophysiology, Faculty of Biological Sciences, Catholic University of Chile
  • , Fabián M. JaksicAffiliated withLaboratory of Ecology, Faculty of Biological Sciences, Catholic University of Chile
  • , Nibaldo C. InestrosaAffiliated withLaboratory of Neurophysiology, Faculty of Biological Sciences, Catholic University of Chile

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Summary

  1. 1.

    An ultrastructural, histochemical, and biochemical study of the electric organ of the South American Torpedinid ray,Discopyge tschudii, was carried out.

     
  2. 2.

    Fine structural cytochemical localization of acetylcholinesterase (AChE) indicated that most of the esterase was associated with the basal lamina. Electron microscopy indicated no marked differences in the electrocyte ultrastructure betweenDiscopyge andTorpedo californica.

     
  3. 3.

    Discopyge electric organ possessed three molecular forms, two asymmetric forms (16 S and 13 S) and one globular hydrophobic form (6.5 S). The asymmetric 16 S AChE form was solubilized by heparin, a sulfated glycosaminoglycan, suggesting that heparin-like macromolecules are involved in the binding of the enzyme to the basal lamina.

     
  4. 4.

    Our results show that cell-free translated AChE peptides, synthesized usingDiscopyge electric organ poly (A+) RNA, correspond to a main band of 62,000 daltons which probably represents the catalytic subunit of the asymmetric AChE.

     

Key words

16 S AChE synaptic basal lamina heparan sulfate proteoglycans cell-free synthesis of AChE electric organ acetylcholinesterase Discopyge tschudii