Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0233565 (bradykinesia)
 2,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Abnormal iron accumulations are frequently observed in the brains of patients with Parkinson's disease and in normal aging. Iron metabolism is regulated in the CNS by iron regulatory proteins (IRP-1 and IRP-2). Mice engineered to lack IRP-2 develop abnormal motoric behaviors including tremors at rest, abnormal gait, and bradykinesia at middle to late age (18 to 24 months). To further characterize the dopamine (DA) systems of IRP-2 -/- mice, we harvested CNS tissue from age-matched wild type and IRP-2 -/- (16-19 months) and analyzed the protein levels of tyrosine hydroxylase (TH), dopamine transporter (DAT), vesicular monoamine transporter (VMAT2), and DA levels in dorsal striatum, ventral striatum (including the core and shell of nucleus accumbens), and midbrain. We further analyzed the phosphorylation of TH in striatum at serine 40, serine 31, and serine 19. In both dorsal and ventral striatum of IRP-2 knockout mice, there was a 20-25% loss of TH protein and accompanied by a approximately 50% increase in serine 40 phosphorylation above wild-type levels. No change in serine 31 phosphorylation was observed. In the ventral striatum, there was also a significant loss (approximately 40%) of DAT and VMAT2. Levels of DA were decreased (approximately 20%) in dorsal striatum, but turnover of DA was also elevated ( approximately 30%) in dorsal striatum of IRP-2 -/- mice. We conclude that iron misregulation associated with the loss of IRP-2 protein affects DA regulation in the striatum. However, the modest loss of DA and DA-regulating proteins does not reflect the pathology of PD or animal models of PD. Instead, these observations support that the IRP-2 -/- genotype may enable neurobiological events associated with aging.
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PMID:Neurochemical investigations of dopamine neuronal systems in iron-regulatory protein 2 (IRP-2) knockout mice. 1605 92

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is characterized by the loss of dopamine neurons in the substantia nigra pars compacta, culminating in severe motor symptoms, including resting tremor, rigidity, bradykinesia, and postural instability. In addition to motor deficits, there are a variety of nonmotor symptoms associated with PD. These symptoms generally precede the onset of motor symptoms, sometimes by years, and include anosmia, problems with gastrointestinal motility, sleep disturbances, sympathetic denervation, anxiety, and depression. Previously, we have shown that mice with a 95% genetic reduction in vesicular monoamine transporter expression (VMAT2-deficient, VMAT2 LO) display progressive loss of striatal dopamine, L-DOPA-responsive motor deficits, alpha-synuclein accumulation, and nigral dopaminergic cell loss. We hypothesized that since these animals exhibit deficits in other monoamine systems (norepinephrine and serotonin), which are known to regulate some of these behaviors, the VMAT2-deficient mice may display some of the nonmotor symptoms associated with PD. Here we report that the VMAT2-deficient mice demonstrate progressive deficits in olfactory discrimination, delayed gastric emptying, altered sleep latency, anxiety-like behavior, and age-dependent depressive behavior. These results suggest that the VMAT2-deficient mice may be a useful model of the nonmotor symptoms of PD. Furthermore, monoamine dysfunction may contribute to many of the nonmotor symptoms of PD, and interventions aimed at restoring monoamine function may be beneficial in treating the disease.
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PMID:Nonmotor symptoms of Parkinson's disease revealed in an animal model with reduced monoamine storage capacity. 1982 98