Tyramide signal amplification in brain immunocytochemistry: adaptation to electron microscopy

The tyramide signal amplification (TSA) technique is well-established in li ght microscopic immunohistochemistry and in situ hybridization to improve t he signal-to-noise ratio. The present study deals with its adaptation to th e electron microscopic level using the pre-embedding technique and a modifi ed protocol. The outcome of immunolabeling of most of the antigens tested i n brain tissue, including endothelial and neuronal nitric oxide synthase, g lial fibrillary acidic protein, and isolectin B4, was greatly improved. If signal amplification is required, the TSA-technique proved to be reliable w ith high specificity and good ultrastructural resolution. (C) 1999 Elsevier Science B.V. All rights reserved.