Dopamine-induced changes in protein phosphorylation and polyphosphoinositide metabolism in rat hippocampus.
Effects of dopamine (DA) on endogenous phosphorylation of hippocampal proteins and polyphosphoinositides were studied in subcellular fractions from a crude mitocondrial/synaptosomal preparation. DA induced a concentration-dependent decrease in the in vitro phosphorylation of the protein B-50 (-22.1% at 10(-5) M DA), whereas no changes were found in phosphoproteins in other subcellular fractions. Treatment of hippocampal slices with 5 X 10(-4) M DA resulted in a 45.8% increase in post hoc phosphorylation of B-50 in SPM and it affected post hoc phosphorylation of several proteins in a cytosolic fraction. In vitro phosphorylation of SPM with DA (5 X 10(-4) M) increased endogenous TPI phosphorylation (+51.6%), whereas treatment of slices with DA (5 X 10(-4) M) resulted in a 39.4% decrease in post hoc TPI phosphorylation. This decrease could be blocked by haloperidol. Significant changes induced by DA (5 X 10(-4) M) were also found in 32P-incorporation into PA (in vitro: -32.4% and post hoc: +39.3%), but were not found in DPI labeling. The data provide evidence for DA-induced changes in phosphorylation of proteins and polyphosphoinositides in rat hippocampal SPM.
D000818:Animals; D004298:Dopamine / Q000494:pharmacology*; D006220:Haloperidol / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains
D009419:Nerve Tissue Proteins; D010716:Phosphatidylinositols; D006220:Haloperidol; D004298:Dopamine