The effect of beta-subunit assembly on function and localization of the colonic H+,K+-ATPase alpha-subunit.

Background: Previous experiments from our laboratory have demonstrated that HKalpha(2) coimmunoprecipitated with beta(1)-Na(+),K(+)-ATPase. Although HKalpha(2) is expressed abundantly in the apical membrane of distal colon, the demonstration that beta(1) localizes to this same membrane in distal colon has not been demonstrated previously.

Methods: Immunolocalization was performed in distal colon using a polyclonal antibody against HKalpha(2) and a monoclonal antibody against beta(1).

The carboxy terminus of the colonic H(+), K(+)-ATPase alpha-subunit is required for stable beta subunit assembly and function.

Background: The present experiments were designed to study the importance of the carboxy-terminus of colonic H(+), K(+)-ATPase alpha-subunit (HKalpha(2)), for both function as well as integrity of assembly with beta1-Na(+), K(+)-ATPase.

Methods: For this purpose, a mutation of 84 amino acids in the carboxy-terminus was created (DeltaHKalpha(2)) and HEK-293 cells were used as expression systems for functional studies using (86)Rb(+)-uptake, coimmunoprecipitation using specific antibodies and fluorescence microscopy using green fluorescent protein.

Results: The results demonstrate that comparable levels of expression of HKalpha(2) and DeltaHKalpha(2) mRNA were observed when cells were cotransfected with beta1 subunit.

Elevated neuronal nitric oxide synthase expression in chronic haloperidol-treated rats.

Long-term administration of neuroleptic drugs, such as haloperidol, in the management of psychiatric disorders may adversely cause an irreversible neurological syndrome of tardive dyskinesia, which is associated with dopamine (DA(2)) receptor supersensitivity in the basal ganglia. Recent studies also indirectly suggest an involvement of nitric oxide synthase (NOS) in dopaminergic supersensitivity; however, chronic neuroleptic effects on neuronal NOS (nNOS) expression in the basal ganglia have not been reported. In this investigation, we treated rats with saline or haloperidol (1 mg/kg, s.

Lysosomal malfunction accompanies alpha-synuclein aggregation in a progressive mouse model of Parkinson's disease.

We have detected granular and filamentous inclusions that are alpha-synuclein- and ubiquitin-immunoreactive in the cytoplasm of dopaminergic and cortical neurons of C57/black mice treated chronically with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and probenecid. The immunoreactive aggregates only become evident several weeks after large-scale dopaminergic cell death and a downregulation of alpha-synuclein gene expression. Numerous lipofuscin granules accumulate alpha-synuclein in the nigral and limbic cortical neurons of treated mice.

Profound astrogenesis in the striatum of adult mice following nigrostriatal dopaminergic lesion by repeated MPTP administration.

Neural progenitor cells are present in the rodent brain throughout adulthood, and can proliferate and differentiate into new neurons and/or glia to repair injury. To explore the repair processes mediated by brain progenitor cells, a selective lesion of the nigrostriatal dopaminergic pathway was induced in young adult mice by repeated administration of the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). A thymidine analog, bromodeoxyuridine (BrdU), was used as a tracer for DNA synthesis to label the dividing cells and their terminal progeny following injury.