title: Stabilizing and rapid thionin staining of TMB-based HRP reaction product.
abstract: Tetramethyl benzidine (TMB) as a substrate for horseradish peroxidase (HRP) histochemistry offers a great advantage over other substrates in its sensitivity but the reaction product is unstable in alcohol. Immersing TMB-reacted sections in methyl salicylate renders the reaction product stable enough so that exposure to ethanol for 10 min causes no detectable loss of HRP labelled neurons. A rapid thionin stain is introduced which, after stabilizing the TMB-based reaction product in methyl salicylate, causes no detectable loss of HRP labelled neurons. These procedures should prove valuable to users of the popular HRP techniques for studying neural connections.
mesh_terms: D001560:Benzidines; D001931:Brain Mapping / Q000379:methods*; D055598:Chemical Phenomena; D002621:Chemistry; D004396:Coloring Agents; D000431:Ethanol; D006651:Histocytochemistry / Q000379:methods*; D006735:Horseradish Peroxidase; D008867:Microtomy / Q000379:methods; D010544:Peroxidases; D010640:Phenothiazines; D012459:Salicylates
chemical_list: D001560:Benzidines; D004396:Coloring Agents; D010640:Phenothiazines; D012459:Salicylates; C021758:3,3',5,5'-tetramethylbenzidine; D000431:Ethanol; D006735:Horseradish Peroxidase; D010544:Peroxidases; C033069:methyl salicylate; C009469:thionine