vS52 Histochemistry (chap. 21) 



solutions: 



Dopa stock solution: 



DL b (3,4 dioxyphenylalanine) phenyl tyrosine^. 0.3 gm. 

 distilled water 300.0 ml. 



Store in refrigerator. Discard when it turns red. 

 Buffer solutions: 



A. disodium hydrogen phosphate 11.0 gm. 



distilled water 1000.0 ml. 



B. potassium dihydrogen phosphate 9.0 gm. 



distilled water 1000.0 ml. 



Buffered Dopa solution: 



stock Dopa solution 25.0 ml. 



buffer solution A 6.0 ml. 



buffer solution B 2.0 ml. 



Filter through fine filter paper. Should be pH. 7.4. 



Buffered control solution: 



distilled water 2.0 ml. 



buffer solution A 6.0 ml. 



buffer solution B 2.0 ml. 



Cresyl violet: 



cresyl violet acetate 0.5 gm. 



distilled water 100.0 mi. 



procedure: 



1. Cut frozen sections, 10 microns. 



2. Wash in distilled water: few seconds. 



3. Treat with buffered Dopa solution, 30-37 °C. The solution be- 

 comes red in about 2 hours, and gradually becomes sepia brown 

 in 3-4 hours. Do not allow sections to remain in a sepia-colored 

 solution; they may overstain. After first 30 minutes, change to a 

 new solution. 



4. Wash in distilled water. 



5. Counterstain in cresyl violet. 



6. Dehydrate, clear and mount. 



results: 



Dopa oxidase — black 



leukocytes, melanoblasts — grey to black 



melanin — yellow brown 



'Eastman Kodak Co. #4915. 



