Eur J Anat, 1 (2): 53-65 (1997)

The Goldi-method for electron microscopy. A X-ray microprobe study

P. Mestres and F.L. Schneider (*)

Institut für Anatomie, Medizinische Fakultat, Universlté: Saarlandes, 0-66421 Homourg/Seer. Germany. (*) Present address: Oepartment of Morphological Sciences, Federal University of Rio Grande do Sul, 90.056-900 Porto Alegre. Brazil.

ABSTRACT Since its introduction by Stell in 1964, the "Golgi method for electron microscopy" has achieved considerable technical improvements, particularly with the so-called de-impregnation procedures such as the gold-toning. In the present study the chemical composition of the precipitantes produced by de-ímpregnation of previously Golgi-rapid stained neurons and glial cells was investigated by X-ray microanal­ ysis. Following de-impregnation procedures were considered: gold-toníng, gold-toning after exposition of the tissue to white light and treat­ ment with a photographic developer with or without gold-toning. Golgi stained ce lis without any treatment served as control. The micro­ probe studies reveal that the precipitates con­ tain both silver and gold after gold-toníng. A complete substitution of the silver located in the silver chromate crystals was only achieved in sections exposed to white light before gold­ toning. After treatment with a photographic developer (chemical reduction), the silver chro­ mate crystals disappeared and silver precípitates of different sizes were found instead. After gold-toníng, the substitution of silver in these precipitates is only partial. As a result of the fix­ ation of the tissue, osmium, uranium and chro­ mium were found in all situations investigated. These findings were discussed in relation with possible chemical mechanisms involved in the de-impregnatíon procedures.

Keywords: Golgi-method, electron microscopy, neurocytology, X-Ray microanalysis.