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

We investigated whether there is neurogenesis in the striatum of aged monkeys, and whether dopamine (DA) depletion induces the genesis of new DA neurons in this structure. Six aged macaques received repeated intraperitoneal injections of bromodeoxyuridine (BrdU) over a 3 week period to label dividing cells. Three macaques were injected in parallel with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to decrease dopaminergic innervation of the striatum. The brains were analysed 3 weeks after the last BrdU injection. In MPTP-treated aged macaques, the number of tyrosine hydroxylase (TH) immunoreactive (ir) striatal neurons increased 2.3-fold compared with controls. These TH-ir striatal cells did not express dopamine beta hydroxylase (DBH) but the dopamine transporter (DAT), suggesting that they are functional DA neurons. They were also negative for calbindin (CB), neuropeptide Y (NPY) and parvalbumin (PV), and a small proportion expressed calretinin (CR). This suggests that these cells stained for TH are interneurons. All these cells also co-expressed glutamic acid decarboxylase (GAD). They thus resemble the small, aspiny, GABAergic interneurons. None of the BrdU-labelled cells in the striatum expressed the neuronal markers neuronal nuclei (NeuN), or GAD or TH, and none of TH-ir cells incorporated BrdU. These data indicate that neurogenesis did not occur in the striatum of aged macaques. The new striatal TH-ir neurons observed after DA depletion was therefore derived from pre-existing GABAergic interneurons. Understanding of the molecular signals mediating this phenotypic shift might help in developing novel and elegant strategies for a cell-based therapy for Parkinson's disease that would avoid many of the drawbacks of cell transplantation.
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PMID:New striatal dopamine neurons in MPTP-treated macaques result from a phenotypic shift and not neurogenesis. 1648 74

The specific expression of fibroblast growth factor 20 (FGF-20) in the adult substantia nigra and the association between FGF-20 mutations and Parkinson's disease provoked exploration of the function of this growth factor. We show by gain- and loss-of-function in vitro experiments that FGF-20 promotes survival and stimulates dopamine (DA) release in a calbindin-negative subset of cells that are preferentially lost in Parkinson's disease. FGF-20 selectively activates tyrosine hydroxylase in calbindin-negative neurons. In the adult substantia nigra, calbindin-negative neurons specifically express high levels of FGFR1 (FGF receptor 1). These data show that FGF signals to elevate DA levels and protect the specific midbrain neuron type at most risk in Parkinson's patients.
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PMID:A specific survival response in dopamine neurons at most risk in Parkinson's disease. 1698 46

Glial cell-line derived neurotrophic factor (GDNF) enhances dopamine (DA) cell survival and fiber outgrowth, and may be beneficial in enhancing cell restorative strategies for Parkinson's disease (PD). However, GDNF may have different roles for transplanted DA cell sub-types. The present in vitro study investigated the effect of GDNF on the survival of rat DA cells displaying a phenotype consistent with either the substantia nigra [A9 cells immunopositive for tyrosine hydroxylase (TH) and G-protein-gated inwardly rectifying potassium channel subunit 2 (GIRK2)] or with the ventral tegmental area [A10 cells immunopositive for TH and calbindin]. It was found that a single exposure of GDNF enhanced the number of DA cells of an A9 phenotype, without affecting DA cells of an A10 phenotype. Conversely, repeated GDNF exposure did not alter the survival of A9 phenotypic cells, but doubled the percentage of A10 cells. It was concluded that GDNF administration may affect dopaminergic cells differently depending on time and degree of GDNF exposure. For cell transplantation in PD, long-term GDNF administration may result in detrimental effects for transplanted A9 TH+ cells as this may introduce competition with A10 TH+ cells for survival and fiber outgrowth into the host striatum. These results may have important implications for clinical neural transplantation in PD.
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PMID:Differential effects of glial cell line-derived neurotrophic factor on A9 and A10 dopamine neuron survival in vitro. 1758 36

Our work aimed to provide a topographical analysis of all known ionotropic P2X(1-7) and metabotropic P2Y(1,2,4,6,11-14) receptors that are present in vivo at the protein level in the basal ganglia nuclei and particularly in rat brain slices from striatum and substantia nigra. By immunohistochemistry-confocal and Western blotting techniques, we show that, with the exception of P2Y(11,13) receptors, all other subtypes are specifically expressed in these areas in different amounts, with ratings of low (P2X(5,6) and P2Y(1,6,14) in striatum), medium (P2X(3) in striatum and substantia nigra, P2X(6,7) and P2Y(1) in substantia nigra) and high. Moreover, we describe that P2 receptors are localized on neurons (colocalizing with neurofilament light, medium and heavy chains) with features that are either dopaminergic (colocalizing with tyrosine hydroxylase) or GABAergic (colocalizing with parvalbumin and calbindin), and they are also present on astrocytes (P2Y(2,4), colocalizing with glial fibrillary acidic protein). In addition, we aimed to investigate the expression of P2 receptors after dopamine denervation, obtained by using unilateral injection of 6-hydroxydopamine as an animal model of Parkinson's disease. This generates a rearrangement of P2 proteins: most P2X and P2Y receptors are decreased on GABAergic and dopaminergic neurons, in the lesioned striatum and substantia nigra, respectively, as a consequence of dopaminergic denervation and/or neuronal degeneration. Conversely, P2X(1,3,4,6) on GABAergic neurons and P2Y(4) on astrocytes augment their expression exclusively in the lesioned substantia nigra reticulata, probably as a compensatory reaction to dopamine shortage. These results disclose the presence of P2 receptors in the normal and lesioned nigro-striatal circuit, and suggest their potential participation in the mechanisms of Parkinson's disease.
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PMID:Mapping P2X and P2Y receptor proteins in striatum and substantia nigra: An immunohistological study. 1840 52

The protein alpha-synuclein is implicated in the development of Parkinson's disease. The molecule forms Lewy body aggregates that are hallmarks of the disease, has been associated with the spread of neuropathology from the peripheral to the CNS, and appears to be involved with the autonomic disorders responsible for the gastrointestinal (GI) symptoms of individuals afflicted with Parkinson's. To characterize the normative expression of alpha-synuclein in the innervation of the GI tract, we examined both the postganglionic neurons and the preganglionic projections by which the disease is postulated to retrogradely invade the CNS. Specifically, in Fischer 344 and Sprague-Dawley rats, immunohistochemistry in conjunction with injections of the tracer Dextran-Texas Red was used to determine, respectively, the expression of alpha-synuclein in the myenteric plexus and in the vagal terminals. Alpha-synuclein is expressed in a subpopulation of myenteric neurons, with the proportion of positive somata increasing from the stomach (approximately 3%) through duodenum (proximal, approximately 6%; distal, approximately 13%) to jejunum (approximately 22%). Alpha-synuclein is co-expressed with the nitrergic enzyme nitric oxide synthase (NOS) or the cholinergic markers calbindin and calretinin in regionally specific patterns: approximately 90% of forestomach neurons positive for alpha-synuclein express NOS, whereas approximately 92% of corpus-antrum neurons positive for alpha-synuclein express cholinergic markers. Vagal afferent endings in the myenteric plexus and the GI smooth muscle do not express alpha-synuclein, whereas, virtually all vagal preganglionic projections to the gut express alpha-synuclein, both in axons and in terminal varicosities in apposition with myenteric neurons. Vagotomy eliminates most, but not all, alpha-synuclein-positive neurites in the plexus. Some vagal preganglionic efferents expressing alpha-synuclein form varicose terminal rings around myenteric plexus neurons that are also positive for the protein, thus providing a candidate alpha-synuclein-expressing pathway for the retrograde transport of putative Parkinson's pathogens or toxins from the ENS to the CNS.
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PMID:Alpha-synuclein-immunopositive myenteric neurons and vagal preganglionic terminals: autonomic pathway implicated in Parkinson's disease? 1840 22

Pituitary adenylate cyclase-activating polypeptide (PACAP) is neuroprotective in animal models of different brain pathologies and injuries, including cerebral ischemia, Parkinson's disease, and different types of retinal degenerations. We have previously shown that PACAP is protective against monosodium glutamate (MSG)-induced retinal degeneration, where PACAP-treated retinas has more retained structure and PACAP induces anti-apoptotic while it inhibits pro-apoptotic signaling pathways. The aim of the present study was to investigate cell-type specific effects of PACAP in MSG-induced retinal degeneration by means of immunohistochemistry. Rat pups received MSG (2 mg/g b.w.) applied on postnatal days 1, 5, and 9. PACAP (100 pmol in 5 microl saline) was injected into the right vitreous body, while the left eye received only saline. Retinas were processed for immunocytochemistry after 3 weeks. Immunolabeling was determined for vesicular glutamate transporter 1, tyrosine hydroxylase, calretinin, calbindin, parvalbumin, and vesicular gamma-aminobutyric acid (GABA) transporter. In the MSG-treated retinas, the cell bodies and processes in the inner nuclear, inner plexiform, and ganglion cell layers displayed less immunoreactivity for all antisera. Apart from photoreceptors, only one major retinal cell type examined in this study; the calbindin-immunoreactive horizontal cell seemed not to be affected by MSG application. After simultaneous application of MSG and PACAP, staining of retinas was similar to that of normal eyes, with no significant alterations in immunoreactive patterns. These findings further support the neuroprotective function of PACAP in MSG-induced retinal degeneration.
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PMID:PACAP-mediated neuroprotection of neurochemically identified cell types in MSG-induced retinal degeneration. 1841 35

This study provides the first immunohistochemical evidence of the presence and distribution patterns in the rat spinal cord of alpha-synuclein (alpha-Syn), a soluble acidic protein, widely expressed in the CNS and closely associated to the pathogenesis of neurodegenerative conditions such as Parkinson's and Alzheimer's diseases. We used two novel homemade monoclonal antibodies (2E3 and 3D5) recognizing two different epitopes of alpha-Syn. Both antibodies localized alpha-Syn within the nerve terminals, whereas 3D5 alone also localized it within the neuronal nuclei. alpha-Syn-immunoreactive nervous elements were widely recognized throughout rat spinal cord and in almost all the gray matter laminae. However, they appeared particularly concentrated within laminae I, II, VII and X and more scattered in the others. Double immunofluorescent labeling showed that alpha-Syn colocalized with synaptophysin in the presynaptic nerve terminals, with neuropeptide Y (NPY) in lamina I, II, IX and X, and had close relationships with tyrosine hydroxylase (TH) immunoreactive neurons in laminae VII and X. Interestingly, the alpha-Syn-immunoreactive nerve elements, in lamina X, contained little of calbindin-28KD and calretinin-31KD. Our findings could help in understanding the genesis of some early clinical symptoms of Parkinson's disease (PD), such as pain and dysautonomic disorders, and indicate the spinal cord as their probable starting point, according to the ascending theory of PD, proposed by Braak.
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PMID:Immunolocalization of alpha-synuclein in the rat spinal cord by two novel monoclonal antibodies. 1911 1

Parkinson's disease is a neurodegenerative disorder where dopamine neurons in the substantia nigra of ventral mesencephalon undergo degeneration. In addition to the loss of dopamine neurons, noradrenaline neurons in the locus coeruleus degenerate, actually to a higher extent than the dopamine neurons. The interaction between these two nuclei is yet not fully known, hence this study was undertaken to investigate the role of locus coeruleus during development of dopamine neurons utilizing the intraocular grafting model. Fetal ventral mesencephalon and locus coeruleus were implanted either as single grafts or co-grafts, placed in direct contact or at a distance. The results revealed that the direct attachment of locus coeruleus to ventral mesencephalon enhanced graft volume and number of tyrosine hydroxylase (TH)-positive neurons in ventral mesencephalic grafts. Cell counts of subpopulations of TH-positive neurons also immunoreactive for aldehyde dehydrogenase 1-A1 (ALDH1) or calbindin, revealed improved survival of ALDH1/TH-positive neurons. However, the number of calbindin/TH-positive neurons was not affected. High density of dopamine-beta-hydroxylase (DBH)-positive innervation in the ventral mesencephalon placed adjacent to locus coeruleus was correlated to the improved survival. Ventral mesencephalic tissue, implanted at a distance to locus coeruleus, did not demonstrate improved survival, although DBH-positive nerve fibers were detected. In conclusion, the direct contact of locus coeruleus resulting in dense noradrenergic innervation of ventral mesencephalon is beneficial for the survival of ventral mesencephalic grafts. Thus, when trying to rescue dopamine neurons in Parkinson's disease, improving the noradrenergic input to the substantia nigra might be worth considering.
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PMID:Locus coeruleus promotes survival of dopamine neurons in ventral mesencephalon. An in oculo grafting study. 1915 Apr 47

Dopaminergic neurons of the substantia nigra (SN) and ventral tegmental area (VTA) are collectively implicated in motor- and reward-related behaviors. However, dopaminergic SN and VTA neurons differ on several functional levels, and dopaminergic SN neurons themselves vary in their intrinsic electrical properties, neurochemical characteristics and connections. This heterogeneity is not only important for normal function; calbindin (CB) expression by some dopaminergic SN neurons has been linked with their increased survival in Parkinson's disease. To test whether the activity of CB-negative and CB-positive dopaminergic SN neurons differs during distinct spontaneous and driven brain states, we recorded single units in anesthetized rats before, during and after aversive somatosensory stimuli. Recorded neurons were juxtacellularly labeled, confirmed to be dopaminergic, and tested for CB immunoreactivity. During cortical slow-wave activity, the firing of most dopaminergic neurons was slow and regular/irregular and unrelated to cortical slow oscillations. During spontaneous cortical activation, dopaminergic SN neurons fired in a more regular manner, with fewer bursts, but did not change their firing rate. Regardless of brain state, CB-negative dopaminergic neurons fired significantly faster than CB-positive dopaminergic neurons. This difference in firing rate was not mirrored by different firing patterns. Most CB-negative and CB-positive dopaminergic neurons did not respond to the aversive stimuli; of those that did respond, most were inhibited. We conclude that CB-negative and CB-positive dopaminergic neurons exhibit different activities in vivo. Furthermore, the firing of dopaminergic SN neurons is brain state-dependent, and, unlike dopaminergic VTA neurons, they are not commonly recruited or inhibited by aversive stimuli.
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PMID:Activity of neurochemically heterogeneous dopaminergic neurons in the substantia nigra during spontaneous and driven changes in brain state. 1926 87

The main transplantation strategy in Parkinson's disease has been to place dopaminergic grafts not in their ontogenic site, the substantia nigra, but in their target area, the striatum with contrasting results. Here we have used green fluorescent protein transgenic mouse embryos as donors of ventral mesencephalic cells for transplantation into the pre-lesioned substantia nigra of an adult wild-type host. This allows distinguishing the transplanted cells and their projections from those of the host. Grafted cells integrated within the host mesencephalon and expressed the dopaminergic markers tyrosine hydroxylase, vesicular monoamine transporter 2 and dopamine transporter. Most of the dopaminergic cells within the transplant expressed the substantia nigra marker Girk2 while a lesser proportion expressed the ventral tegmental area marker calbindin. Mesencephalic transplants developed projections through the medial forebrain bundle to the striatum, increased striatal dopamine levels and restored normal behavior. Interestingly, only mesencephalic transplants were able to restore the nigrostriatal projections as dopamine neurons originating from embryonic olfactory bulb transplants send projections only in the close vicinity of the transplantation site that did not reach the striatum. Our results show for the first time the ability of intranigral foetal dopaminergic neurons grafts to restore the damaged nigrostriatal pathway in adult mice. Together with our previous findings of efficient embryonic transplantation within the pre-lesioned adult motor cortex, these results demonstrate that the adult brain is permissive to specific and long distance axonal growth. They further open new avenues in cell transplantation therapies applied for the treatment of neurodegenerative disorders such as Parkinson's disease.
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PMID:Anatomical and functional reconstruction of the nigrostriatal pathway by intranigral transplants. 1961 2


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