title: Enhanced ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine reaction product.
abstract: 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 degrees 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 degrees 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.
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D001560:Benzidines; D001933:Brain Stem / Q000648:ultrastructure*; D002415:Cats; D005724:Ganglia / Q000648:ultrastructure*; D006735:Horseradish Peroxidase; D007202:Indicators and Reagents; D008854:Microscopy, Electron / Q000379:methods
chemical_list: D001560:Benzidines; D007202:Indicators and Reagents; C021758:3,3',5,5'-tetramethylbenzidine; D006735:Horseradish Peroxidase