6-Hydroxydopamine [BSA]

Argonaute proteins are the core components of the microRNP/RISC. The biogenesis and function of microRNAs and endo- and exo- siRNAs are regulated by Ago2, an Argonaute protein with RNA binding and nuclease activities. Currently, there are no in vitro assays suitable for large-scale screening of microRNP/RISC loading modulators. We describe a novel in vitro assay that is based on fluorescence polarization of TAMRA-labeled RNAs loaded to human Ago2. Using this assay, we identified potent small-molecule inhibitors of RISC loading, including aurintricarboxylic acid (IC50 = 0.47 mu M), suramin (IC50 = 0.69 mu M), and oxidopamine HCL (IC50 = 1.61 mu M). Small molecules identified by this biochemical screening assay also inhibited siRNA loading to endogenous Ago2 in cultured cells.

PURPOSE: To investigate the role of adenosine A(2A) receptors on 6-OHDA-induced motor disorder in rat. METHODS: In order to induce experimental model of Parkinson's disease, 6-hydoxydopamine (8 mu g/rat) was injected unilaterally into the SNc. After three weeks as a recovery period, 6-OHDA-induced bradykinesia and balance disturbances were assessed by using beam traversal test 10, 30 and 60 minutes after intraperitoneal injections of the drugs (caffeine, SCH58261). RESULTS: The results showed that 6-OHDA (8 mu g/rat, Intra-SNc) induced motor disorders of Parkinson's disease and increased elapsed time in the beam test (p<0.001). Injection of caffeine (30 mg/kg, i.p.) and SCH58261 (2 mg/kg, i.p.) attenuated elapsed time on beam (p<0.01 and p<0.001). We showed that acute administration of caffeine and SCH 58261 can improve the 6-OHDA-induced bradykinesia and motor disturbance. CONCLUSION: Adenosine A(2A) R antagonists improve 6-OHDA-motor deficit and this effect seems to be mediated by the inhibition of A(2A) presynaptic receptors in substantia nigra pars compacta.