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Recently, alterations in dopamine signaling have been implicated in Huntington's disease. In this work, dopamine release and uptake was measured in striatal slices from the R6/2 transgenic mouse model of Huntington's disease using fast-scan cyclic voltammetry at carbon-fiber microelectrodes. Dopamine release in brain slices from 6-week-old R6/2 mice is substantially reduced (53% of wild type), while dopamine uptake is unaffected. In agreement with this, R6/2 mice injected with the dopamine uptake inhibitor cocaine exhibited a blunted motor activity response (54% of wild type). At 10 weeks of age, an even more dramatic motor activity decrease in response to cocaine injection (21% of wild type) was observed. Moreover, the pre-drug activity of 10-weekold R6/2 mice was significantly reduced (by 37%) compared with 6-week-old R6/2 mice. Striatal dopamine release decreased with age, indicating that progressive alterations in dopaminergic pathways may affect motor activity. The inhibition constants of cocaine and methamphetamine (METH) determined in brain slices differed little between genotype or age group, suggesting that the decreased responses to cocaine and METH arise from compromised dopamine release rather than differences in uptake or drug action. Collectively, these data demonstrate (i) a reduction in the ability of dopamine terminals to release dopamine and (ii) the importance of this attenuation of release on the motor symptoms of Huntington's disease.

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We used synthetic mono-to hexasaccharides that mimic the fragments of the O-antigen of Ogawa and Inaba O-polysaccharides (2-4), together with certain analogs of their monosaccharides to evaluate specificity. The binding of three immunoglobulins G (two specific for Ogawa and one specific for Ogawa/ Inaba) and of two immunoglobulins A (one specific for Ogawa and one specific for Inaba/Ogawa) were characterized by ligand-induced fluorescence titration or ELISA inhibition. The cDNA sequences of these antibodies are also presented in this report. MATERIALS AND METHODSMonoclonal Antibodies-Murine ascites fluids of A-20-6 and S-20-4 both contain vibriocidal IgG 1 specific for Ogawa-LPS. I-24-2, in contrast, contains IgG 3 specific for both serotypes Ogawa and Inaba-LPS, and it has low vibriocidal activity (5) (clone S-20-4 comes from the same hybridoma cells as clone S-20-3 described in this reference). Murine ascites fluid 2D6 and ZAC-3 contain IgA specific for Ogawa-LPS and IgA specific for Inaba/Ogawa-LPS, respectively. The latter two hybridomas were gifts from Drs. Marian Neutra, Harvard Medical School, and Dr. Richard Weltzin, Oravax, Cambridge, MA (1, 6) and were grown in BALB/c mice. IgGs were purified using ImmunoPure® (G) IgG purification kits (Pierce). Briefly, ascites fluid (2 ml, clarified by centrifugation) was mixed with ImmunoPure® (G) binding buffer (2 ml) and applied to a protein G column. After washing the column with 5 ϫ 2-ml aliquots of the ImmunoPure® (G) binding buffer, the bound IgG was eluted with 6 ml of ImmunoPure® (G) elution buffer, dialyzed against PBS, pH 7.4 (2000 ml) for three changes at 0°C, frozen, and labeled. The purified A-20-6, S-20-4, and I-24-2 showed a single arc of precipitation versus goat anti-mouse IgG 1 and IgG 3 , respectively (heavy chainspecific), and goat anti-whole mouse serum (Sigma) by immunoelectrophoresis. IgAs were purified from ascites fluid by 40% ammonium sulfate precipitation and anion-exchange DEAE-Sephadex A-25 chromatography (7). Monomeric IgA was obtained by mild reduction with 5 mM 1,4-dithiothreitol (Sigma) and alkylation with 11 mM 2-iodoacetamide (Sigma), followed by re-adsorption of the sample on DEAESephadex A-25 and elution with PBS, pH 7.4. The purity of IgAs was also verified by immuno-electrophoresis against anti-mouse IgA and serum and SDS-polyacrylamide gel electrophoresis.LPS and Synthetic Oligosaccharides-V. cholerae O:1 LPSs were obtained from acetone-treated cells of strain 569B, classical biotype, serotype Inaba, lot VC1219; strain 3083, classical biotype, serotype Ogawa; and V. cholerae O:139 Bengal, strain 4450. Salmonella paratyphi A LPS was a field isolate in Nepal, strain NTP-6. All LPSs were purified as described (8) and at 2 mg/ml showed negative tests (Coomassie Blue) for protein. Severely base-degraded V. cholerae O:139 LPS (9) was a gift from Dr. Andrew D. Cox, National Research Council, Ottawa, Canada. De-O-acylated Ogawa-LPS (10) was oxidized in aqueous 0.8% periodate solution for 3 days in the dark, dialyzed, and freezedried a...

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