Double immunohistochemical detection of transmitter phenotype of proliferating cells using bromodeoxyuridine

We describe a new method that can determine transmitter phenotype of proliferating nerve cells at a given age. The procedure is based on indirect sequential double antigen immunofluorescence histochemistry for transmitter-synthesizing enzymes (glutamic acid decarboxylase and tyrosine hydroxylase) and the thymidine analogue, bromodeoxyuridine. The method permits simple, rapid, and effective anatomical detection, and promises to reduce certain limitations inherent in a combination with tritiated thymidine autoradiography. Employing this technique, we observed that many striatal cells expressing gamma-aminobutyric acid (GABA) and nigral cells expressing dopamine undergo the final mitosis at embryonic days 13-14 in the rat.