Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.21 (CPT)
 4,580 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron-emission-tomography (PET) studies, net blood-brain clearance of [18F]-fluoro-l-DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood-brain clearance of FDOPA (K(in)(app)) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes-of-interest. The Wisconsin-Card-Sorting-Test (WCST), Stroop-Test, Trail-Making-Test (TMT-A/B), and Continuous-Performance-Test (CPT-M) had been administered previously to the same subjects. No correlation of K(in) (app) with perseverative errors in WCST or age could be found. However, there were significant positive correlations between the magnitude of K(in)(app) in caudate nucleus, putamen, and midbrain with performance of the TMT-B, CPT-M, and the Stroop test. Highest correlations were found between the time needed to perform the Stroop interference task and the K(in)(app) of striatal areas (Caudate nucleus: -0.780, P = 0.005; putamen: -0.870, P < 0. 001). Thus, the present findings reveal a strong correlation between dopamine synthesis capacity in striatum of healthy volunteers and performance of cognitive tasks linked to the prefrontal cortex.
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PMID:'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET investigation. 1713 2

Adenosine A(1) and A(2A) receptors are colocalized with dopamine D(1) and D(2) receptors on striatal projection neurons and adenosine antagonists have been proposed as adjunctive therapies to l-DOPA treatment in Parkinson patients. We present here two studies examining the effects of selective and non-selective adenosine antagonists in two rodent models of parkinsonian tremor. Tremulous jaw movements (TJMs) were induced by either the dopamine antagonist pimozide (1.0 mg/kg) or the acetylcholine agonist tacrine (5.0 mg/kg), and were quantified by a trained observer who was blind to the treatment conditions. Animals were treated concomitantly with either caffeine (10.0 mg/kg non-selective adenosine antagonist), 8-cyclopentyltheophylline (CPT; 10.0 mg/kg; selective A(1) antagonist) or SCH58261 (8.0 mg/kg; selective A(2A) antagonist). Caffeine, CPT and SCH58261 all significantly reduced pimozide-induced TJM activity. Surprisingly administration of adenosine antagonists did not reduce tacrine-induced TJMs, and in the case of SCH58261 significantly increased TJMs compared to tacrine alone. These results indicate that antagonism at A(1) receptors may be more important for the reduction of tremor than previously supposed. Furthermore they indicate that dopamine antagonist-induced tremor models and acetylcholine agonist-induced tremor models are not entirely similar, and caution should be taken when using these models to evaluate novel therapeutics.
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PMID:Differential effects of adenosine antagonists in two models of parkinsonian tremor. 1960 22