Modification of the Silver Proteinate Technique for Cultured Nerve Cells Impregnation Protozoa and

Silver impregnation with silver-pro- tein compounds is widely used for staining tissue sections and cell cultures. Some authors report that the results obtained with these methods have not always been reproducible because the re- agent's composition varies according to the man- ufacturer. To avoid this problem in the method described in this paper, a silver proteinate, pro- duced in our own laboratory is used. Although our method is based on Bodian's, the modifica- tions we have made allows its use for both free- living cells (protozoa) and cells grown in culture (nerve cells). The significant modifications are 1) different fixation, 2) postfixation with Cajal's for- mol-bromide, 3) changes in the duration of the impregnation steps technique and 4) elimination of metallic copper. The method reported here en- ables us to use silver proteinate whenever we require it and to control the composition of the silver proteinate. This technique can be used for cells cultured in either plastic or glass.