Dopaminergic striatal synaptosomes can be detected and isolated with a fluorescence‐activated cell sorter (FACS). In the present study, two antigens were detected simultaneously with primary antisera raised in different species and species‐specific fluorescent secondary antibodies with different emission spectra. Double‐label FACS analysis was used to determine whether tyrosine hydroxylase (TH) and the alpha subunit of Gαo (Gαo) are colocalized in striatal synaptosomes. Rabbit antibodies generated against a synthetic fragment of Gαo (corresponding to amino acids 22–35) combined with fluorescein‐conjugated secondary antibodies were used to detect Gαo‐containing striatal synaptosomes. Preadsorption of Gαo antiserum with the synthetic peptide antigen reduced labeling to the level obtained with preimmune serum. Approximately 65–75% of striatal synaptosomes were specifically labeled by Gαo antiserum. Tyrosine hydroxylase‐containing synaptosomes were detected with a mouse monoclonal antibody to TH and R‐phycoerythrin‐conjugated secondary antibody. They comprised 15–17% of total striatal synaptosomes. Double‐label studies indicated that at least 50% of TH‐containing synaptosomes also contained Gαo. These finding suggest that Gαo may not be a protein component of all striatal nerve terminals, and provide a basis for a role for Gαo in signal transduction within subpopulations of intrinsic and afferent nerve terminals, including those of nigrostriatal dopamine neurons.
- Flow cytometry
- Nigrostriatal dopamine neurons
- Signal transduction
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience