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Characterization of the distribution of G αo in rat striatal synaptosomes and its colocalization with tyrosine hydroxylase
Author(s) -
Wolf Marina E.,
Granneman James G.,
Kapatos Gregory
Publication year - 1991
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890090110
Subject(s) - tyrosine hydroxylase , colocalization , synaptosome , antiserum , microbiology and biotechnology , chemistry , dopamine , dopaminergic , tyrosine 3 monooxygenase , monoclonal antibody , antibody , biochemistry , biology , enzyme , endocrinology , in vitro , immunology
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 G αo (G αo ) are colocalized in striatal synaptosomes. Rabbit antibodies generated against a synthetic fragment of G αo (corresponding to amino acids 22–35) combined with fluorescein‐conjugated secondary antibodies were used to detect G αo ‐containing striatal synaptosomes. Preadsorption of G αo 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 G αo 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 G αo . These finding suggest that G αo may not be a protein component of all striatal nerve terminals, and provide a basis for a role for G αo in signal transduction within subpopulations of intrinsic and afferent nerve terminals, including those of nigrostriatal dopamine neurons.