Enhanced ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine reaction product

M. A. Henry, L. E. Westrum, L. R. Johnson

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Ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine (HRP-TMB) reaction product within trigeminal ganglion cells and brain stem axons and terminals following HRP injections into the pulpal chambers of cat teeth is enhanced by utilization of a modified osmication procedure that converts the reaction product to a markedly stable and electron-dense form. The results following the use of the modified osmication procedure (pH 5.0 phosphate buffer at 20°C for 12 hours) are compared to results obtained by following Carson's osmication protocol (Carson KA, Mesulam M-M: J Histochem Cytochem 30:425, 1982; Carson KA, Mesulam M-M: In Tracing Neural Connections with Horseradish Peroxidase. Edited by M-M Mesulam. J Wiley, Chichester, England, 1982, p 153-184) (pH 6.0 phosphate buffer at 45°C for 45 min). The results suggest that the conversion of the HRP-TMB reaction product to an electron-dense form during osmication is intimately associated with the pH of the phosphate buffer and the total time of osmication.

Original languageEnglish (US)
Pages (from-to)1256-1259
Number of pages4
JournalJournal of Histochemistry and Cytochemistry
Issue number12
StatePublished - Jan 1 1985


ASJC Scopus subject areas

  • Anatomy
  • Histology

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