Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The study of neurotransmitter receptors aids in the understanding of the normal anatomy, pharmacology, therapeutics and pathophysiology of disease processes involving the basal ganglia. Receptors may be studied in vitro by homogenate binding experiments, enzyme analysis or quantitative autoradiography and in vivo with positron emission tomography. In the substantia nigra (SN), receptors have been identified for somatostatin, neurotensin, substance P, glycine, benzodiazepine and GABA, opiates, dopamine, angiotensin converting enzyme (ACE) and serotonin. The striatum has receptors for dopamine, GABA and benzodiazepines, acetylcholine, opiates, substance P, glutamate and cholecystokinin. GABA and benzodiazepine receptors are also located in the globus pallidus. In Parkinson's disease, striatal dopamine D-2 receptors are elevated in patients that have not received L-DOPA therapy. This supersensitivity is reversed with agonist therapy. Muscarinic binding to cholinergic receptors seems to correlate with dopamine receptors. Delta opiate receptors are increased in the caudate and mu binding is reduced in the striatum. In the SN of patients with Parkinson's disease, there is reduced binding of somatostatin, neurotensin, mu and kappa opiates, benzodiazepine and GABA and glycine. In Huntington's disease, there is reduced binding of GABA and benzodiazepines, dopamine, acetylcholine, glutamate and CCK. There is increased binding of GABA in both the SN and globus pallidus. Glycine binding is increased in the substantia nigra and ACE is reduced.
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PMID:Receptors in the basal ganglia. 282 9

Whilst the neuropathological correlates of Alzheimer type dementia--cortical neurofibrillary tangles and senile plaques--are well defined, the prevalence of these cortical abnormalities in Parkinson's disease and their relation to dementia is unclear. In a series of 46 consecutive cases of clinically and pathologically established Parkinson's disease the prevalence of mild Alzheimer-type pathology (exceeding the normal but not as extensive as in Alzheimer's disease) was increased 2 to 3 fold compared with an age-matched control group, although there was no obvious relation to the presence or severity of dementia. In a subgroup of Parkinsonian cases (both demented and non-demented), examined neurochemically, there were both similarities (decreased choline acetyltransferase, nicotinic and serotonergic S 1 receptor activities) and distinctions (increased muscarinic receptor binding--particularly to the "L" subtype, and normal serotonergic S 2, somatostatin, and D-aspartate binding together with normal levels of an endogenous nicotine binding inhibitor) compared with a group of cases with Alzheimer's disease. Amongst the various pathological and chemical indices examined, only presynaptic cholinergic markers (including the number of Meynert neurons) and S 1 receptor binding were related to dementia in Parkinson's disease. It is suggested that whilst coincidental classical Alzheimer's disease is infrequent in Parkinson's disease (5% in the present series) Alzheimer's disease itself is distinguished from Parkinson's disease by the formation of numerous neocortical neurofibrillary tangles and a reduction in glutamate uptake, serotonergic S 2 receptors and possibly in endogenous nicotine binding inhibitor.
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PMID:Cortical neuropathological and neurochemical substrates of Alzheimer's and Parkinson's diseases. 282 87

The concentration of neuropeptide Y has been determined in the cortex and hippocampus of subjects with Parkinson's disease and compared to changes of activity of dopamine beta-hydroxylase and concentration of somatostatin. Despite a marked reduction in the concentration of somatostatin in the severely demented subject, in both cortex and hippocampus, no significant change in concentration of NPY was found in either region. This finding therefore suggests that the majority of NPY within the cortex is independent of somatostatin. This study provides some further evidence of neurochemical similarities between the dementia of Parkinson's disease and Alzheimer's disease.
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PMID:Dissociation of neuropeptide Y and somatostatin in Parkinson's disease. 286 Sep 55

The concentrations of somatostatin-like immunoreactivity (SLI) in lateral ventricular fluid of patients with extrapyramidal motor disease were determined by specific radio-immunoassay. Mean SLI levels were significantly lower in patients with Parkinson's disease (mean +/- SEM); 42.9 +/- 2.9 fmol/ml) and in patients with dystonic syndromes (39.4 +/- 3.2) than in patients with benign essential tremor (65.3 +/- 9.7). The lowest levels were found in patients with athetosis (34.7 +/- 5.4). In parkinsonian patients somatostatin levels correlated with the degree of akinesia, rigidity and autonomic disturbances.
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PMID:Ventricular somatostatin-like immunoreactivity in patients with basal ganglia disease. 286 2

Concentrations of somatostatin-like immunoreactivity (SLI) in CSF were reduced in Alzheimer's disease (AD) and multi-infarct dementia (p less than 0.01), but not in normal-pressure hydrocephalus, Parkinson's disease, and Huntington's disease. This suggests that reduced SLI content in AD cerebral cortex is reflected in CSF. Chromatographic characterization of CSF SLI showed no differences between AD and controls. Concentrations of SLI in AD patients overlapped those in both normal subjects and patients with multi-infarct dementia, so that changes in CSF SLI have no diagnostic specificity.
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PMID:CSF somatostatin-like immunoreactivity in dementia. 286 29

The evidence for deficiencies in neurotransmitters in Alzheimer's disease is reviewed. Major losses occur in the subcortical afferent projection systems based on acetylcholine, noradrenaline and serotonin. Within the cortex, somatostatin containing neurones and the large pyramidal cells, presumed to use glutamate/aspartate as transmitters, are the most severely damaged cells. The anatomical distribution of cell loss is explainable if the primary site of damage lies within the cortex; nerve cells are damaged by virtue of their presence within or their connections to this region. The senile plaque may represent the site of this damage and neurofibrillary tangle formation and accumulation may lead to cell death. In patients with Down's syndrome who live past 40 years, changes in transmitters apparently identical to those in Alzheimer's disease occur. The dementia of Parkinson's disease appears related to damage to cholinergic, noradrenergic and dopaminergic systems and may reflect a failure of these subcortical regions to sufficiently "activate" an otherwise undamaged cortex.
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PMID:Neurotransmitter deficits in Alzheimer's disease and in other dementing disorders. 287 73

It is currently believed that Parkinson disease (PD) is due to a degenerative process that independently damages multiple areas of the central and peripheral nervous system. Loss of nigrostriatal dopamine is now widely recognized as being directly related to the motor symptoms in Parkinson's disease. Parkinsonian patients also exhibit symptoms and signs suggestive of hypothalamic dysfunction (e.g. dysautonomia, impaired heat tolerance). The latter clinical features are supported by pathological, biochemical and endocrinological findings. Lewy body formation has been demonstrated in every nucleus of the hypothalamus, specifically the tuberomamillary and posterior hypothalamic. Preferential involvement of the hypothalamus was also noted in patients after post-encephalitic parkinsonism. Loss of dopamine (30-40%) in the hypothalamus of affected patients has been shown in recent studies, and is compatible with the reported abnormalities of growth hormone release in response to L-dopa administration, elevated plasma levels of MSH, and reduced CSF levels of somatostatin and beta-endorphins in these patients. Deranged immunological mechanisms have been found in PD patients including the presence of autoantibodies against sympathetic ganglia neurons, adrenal medulla and caudate nucleus. On the evidence of on pathological studies demonstrating the early vulnerability of the hypothalamus in aging and PD, and the known role of the hypothalamus in immune modulation, we expect that it will be shown that primary damage of the hypothalamus leads to subsequent secondary degeneration of structures receiving direct projections from the hypothalamus. Within this framework, the dopaminergic systems may be damaged, since striatal dopamine synthesis and receptor sensitivity have been shown to be regulated by ACTH and alpha-MSH through direct arcuate nucleus-striatal projections.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The hypothalamus in Parkinson disease. 288 37

The concentrations of somatostatin and choline acetyl transferase (CAT) were measured in nine brains from patients with progressive supranuclear palsy (PSP) and compared with those obtained from 19 matched control brains. In PSP, CAT activity was reduced in the caudate nucleus and limbic areas (amygdala, hippocampus and cingulate cortex) but was not different from controls in neocortical areas (frontal and temporal). Somatostatin concentrations were not different from controls in any region tested. In contrast to Alzheimer's disease and Parkinson's disease, intellectual deterioration in PSP is not associated with a deficit in neocortical somatostatin and CAT levels.
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PMID:Brain somatostatin concentrations do not decrease in progressive supranuclear palsy. 289 95

Corticotropin-releasing hormone-like immunoreactivity (CRH-IR) was measured in control and Huntington's disease brain tissues obtained postmortem. The concentration of CRH-IR was markedly decreased in the caudate/putamen in Huntington's disease; the concentration of somatostatin-like immunoreactivity measured in the same extracts was significantly increased in the caudate/putamen in Huntington's disease compared with the control group. In contrast to previously reported decreases in CRH-IR in the cerebral cortex in Alzheimer's disease, Parkinson's disease and progressive supranuclear palsy, no significant differences were observed in the concentrations of CRH-IR between controls and Huntington's disease in frontal, parietal, temporal, occipital and cingulate cortex and in globus pallidus.
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PMID:Corticotropin-releasing hormone (CRH) is decreased in the basal ganglia in Huntington's disease. 289 55

A reduction in the levels of somatostatin-like immunoreactivity (SLI) and somatostatin binding sites in the cerebral cortex has been previously reported to occur in Alzheimer's disease (AD) and Parkinson's disease with associated dementia. In the present study, the levels of both SLI and high affinity [3H]somatostatin binding sites have been measured in the frontal (Brodmann area 9) and temporal (Brodmann area 21) cortices in patients with presenile and senile Alzheimer's disease, and in mentally normal and cognitively impaired cases of Parkinson's disease. The results were compared with those obtained from a group of normal patients matched for age and postmortem delay. No significant changes in SLI or somatostatin binding in the frontal and temporal cortex were found between any of the disease groups. These results suggest that involvement of the somatostatinergic system in AD or Parkinson's disease is not a consistent or primary neurochemical feature of these diseases.
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PMID:Cortical somatostatinergic system not affected in Alzheimer's and Parkinson's diseases. 290 99


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