Evaluation of Cognitive Function in Relation to Progression of Parkinson Disease.

OBJECTIVE: Cognitive impairments are among the nonmotor symptoms in patients with Parkinson disease. Understanding the cognitive impairments in patients with Parkinson disease may be critical for developing effective rehabilitation interventions. The aims of this study were to assess cognitive function in patients with Parkinson disease using the Wechsler Adult Intelligence Scale Third Edition, and the Wechsler Memory Scale Revised and to investigate how cognitive impairments relate to progression of disease in patients with Parkinson disease according to the Hoehn and Yahr stages. DESIGN: Seventy-eight patients with Parkinson disease participated in the present study. Our study consisted of patients in the following Hoehn and Yahr groups: 1 (no disability, n = 11), 2 (mild, n = 34), 3 (moderate, n = 26), and 4 and 5 (severe, n = 7). Cognitive function was assessed using the Wechsler Adult Intelligence Scale Third Edition, and the Wechsler Memory Scale Revised. RESULTS: The verbal memory was significantly higher in group 1 (106.4 ± 12.0) than in the other groups (2: 90.5 ± 14.0, 3: 89.9 ± 16.9, 4 and 5: 89.6 ± 11.4). Visual memory and delayed recall were similar to the results seen with verbal memory; however, the differences between groups were not statistically significant. The full-scale IQ was not significantly different (1: 107.3 ± 8.1, 2: 96.9 ± 18.2, 3: 96.7 ± 14.8, 4 and 5: 91.7 ± 9.5). CONCLUSIONS: These results suggest that a comprehensive assessment focused on memory impairments is important for applying the appropriate interventions in patients with early-stage Parkinson disease.

Function of taurine transporter (Slc6a6/TauT) as a GABA transporting protein and its relevance to GABA transport in rat retinal capillary endothelial cells.

The purpose of this study was to identify the uptake mechanism of gamma-aminobutyric acid (GABA) via taurine transporter (Slc6a6/TauT) and its relationship with GABA transport at the inner BRB. Rat Slc6a6/TauT-transfected HeLa cells exhibited Na(+)-, Cl(-)-, and concentration-dependent [3H]GABA uptake with a Km of 1.5 mM. Taurine, beta-alanine, and GABA markedly inhibited Slc6a6/TauT-mediated uptake of [3H]GABA. The uptake of [3H]GABA by a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2) was Na(+)-, Cl(-)-, and concentration-dependent with a Km of 2.0 mM. This process was more potently inhibited by substrates of Slc6a6/TauT, taurine and beta-alanine, than those of GABA transporters, GABA and betaine. In the presence of taurine, there was competitive inhibition with a Ki of 74 microM. [3H]Taurine also exhibited competitive inhibition with a Ki of 1.8 mM in the presence of GABA. In conclusion, rat Slc6a6/TauT has the ability to use GABA as a substrate and Slc6a6/TauT-mediated GABA transport appears to be present at the inner BRB.