Quantification of reserve pool dopamine in methionine sulfoxide reductase A null mice.

Methionine sulfoxide reductase A knockout (MsrA-/-) mice, which serve as a potential model for neurodegeneration, suffer from increased oxidative stress and have previously been found to have chronically elevated brain dopamine (DA) content levels relative to control mice. Additionally, these high levels parallel the increased presynaptic DA release. In this study, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes was used to quantify striatal reserve pool DA in knockout mice and wild-type control mice. Reserve pool DA efflux, induced by amphetamine (AMPH), was measured in brain slices from knockout and wild type (WT) mice in the presence of α-methyl-p-tyrosine, a DA synthesis inhibitor. Additionally, the stimulated release of reserve pool DA, mobilized by cocaine (COC), was measured. Both efflux and stimulated release measurements were enhanced in slices from knockout mice, suggesting that these mice have greater reserve pool DA stores than wild-type and that these stores are effectively mobilized. Moreover, dopamine transporter (DAT) labeling data indicate that the difference in measured DA efflux was likely not caused by altered DAT protein expression. Additionally, slices from MsrA-/- and wild-type mice were equally responsive to increasing extracellular calcium concentrations, suggesting that potential differences in either calcium entry or intracellular calcium handling are not responsible for increased reserve pool DA release. Collectively, these results demonstrate that MsrA-/- knockout mice maintain a larger DA reserve pool than wild-type control mice, and that this pool is readily mobilized.

In vivo dopamine release and uptake impairments in rats treated with 3-nitropropionic acid.

Recent evidence has suggested that mitochondrial dysfunction may lead to impaired neurotransmitter exocytosis in transgenic Huntington's disease (HD) model mice. To gain insight into the impact of mitochondrial impairment on striatal dopamine release in vivo, we used fast-scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes to measure dopamine release and uptake kinetics in anesthetized Lewis rats continuously treated for 5 days with 3-nitropropionic acid (3NP). Our results indicate that, even though striatal dopamine content was unchanged, remotely stimulated dopamine release evoked per electrical stimulus pulse ([DA](p)) is decreased in 3NP-treated rats (33% of that observed in sham control rats) and that this decrease is uniform throughout all stereotaxic depths tested. Nevertheless, unlike data collected previously from transgenic HD model rodents, the maximum rate of dopamine uptake (V(max)) in 3NP-treated rats is diminished (30% of controls) while K(m) is unchanged. Treatment with 3NP also resulted in a corresponding decrease in locomotor activity, presumably due in part to the impaired dopamine release. These results indicate that dopamine release is degraded in this HD model, as is observed in transgenic HD model rodents; however, the results also imply that there are fundamental differences in dopamine uptake between 3NP-treated animals and transgenic animals.

Anorectal sigmoid myotomy with ileal anastomosis after subtotal colectomy due to Hirschsprung's enterocolitis: case report and review of the literature

We presented a one year old seven months old patients that had undergone a double barreled proximal ileostomy-sigmoidostomy after resection of most of the ileum, ascending, transverse and descending colon due to Hirschsprung's enterocolitis; that was admitted for anorectal-sigmoid myotomy and ileosigmoidostomy. The advantages of Kasai's procedure (anorectal myotomy with coloanal anastomosis) over the pull-through procedures to treat Hirschsprung's disease are discussed along with the more pertinent literature

Anorectal sigmoid myotomy with ileal anastomosis after subtotal colectomy due to Hirschsprung's enterocolitis: case report and review of the literature.

We presented a one year old seven months old patients that had undergone a double barreled proximal ileostomy-sigmoidostomy after resection of most of the ileum, ascending, transverse and descending colon due to Hirschsprung's enterocolitis; that was admitted for anorectal-sigmoid myotomy and ileosigmoidostomy. The advantages of Kasai's procedure (anorectal myotomy with coloanal anastomosis) over the pull-through procedures to treat Hirschsprung's disease are discussed along with the more pertinent literature.