Antiserum raised against residues 159-168 of the guanine nucleotide-binding protein Gi3-alpha reacts with ependymal cells and some neurons in the rat brain containing cholecystokinin- or cholecystokinin- and tyrosine 3-hydroxylase-like immunoreactivities.
Antibodies raised against a synthetic deca-peptide corresponding to a specific sequence of Gi3-alpha protein (an inhibitory guanine nucleotide-binding protein) were used to analyze Gi3-alpha-like immunoreactivity in brain sections from colchicine-treated rats by indirect immunofluorescence histochemistry. Gi3-alpha-peptide-positive cell bodies were found in the ventral tegmental area and substantia nigra, and these cells were also cholecystokinin (CCK)- and tyrosine 3-hydroxylase-positive. Gi3-alpha-peptide staining was observed in perikarya in the hippocampus and in fibers in the nucleus accumbens, tuberculum olfactorium, bed nucleus of stria terminalis, and a spino-thalamic tract, where it coexisted with CCK-like immunoreactivity as well. No coexistence with CCK occurred in Gi3-alpha-peptide-positive ependymal cells outlining the aqueduct and ventricles. Preadsorption of Gi3-alpha antibodies with CCK-8 or CCK-33 did not alter Gi3-alpha-peptide staining. The occurrence of Gi3-alpha-peptide-like immunoreactivity in CCK-containing neurons may indicate the presence of Gi3-alpha protein and in CCK/dopamine neurons may indicate an association of this Gi protein with dopamine autoreceptors.
D000818:Animals; D001921:Brain / Q000166:cytology* / Q000201:enzymology; D002766:Cholecystokinin / Q000032:analysis* / Q000276:immunology; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000276:immunology*; D007106:Immune Sera; D046911:Macromolecular Substances; D008297:Male; D009474:Neurons / Q000166:cytology* / Q000201:enzymology; D010446:Peptide Fragments / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis* / Q000276:immunology
D007106:Immune Sera; D046911:Macromolecular Substances; D010446:Peptide Fragments; D002766:Cholecystokinin; D014446:Tyrosine 3-Monooxygenase; D019204:GTP-Binding Proteins