Striatum Of Animals Research Articles

Cannabidiol prevents haloperidol-induced vacuos chewing movements and inflammatory changes in mice via PPARγ receptors

The chronic use of drugs that reduce the dopaminergic neurotransmission can cause a hyperkinetic movement disorder called tardive dyskinesia (TD). The pathophysiology of this disorder is not entirely understood but could involve oxidative and neuroinflammatory mechanisms. Cannabidiol (CBD), the major non-psychotomimetic compound present in Cannabis sativa plant, could be a possible therapeutic alternative for TD. This phytocannabinoid shows antioxidant, anti-inflammatory and antipsychotic properties and decreases the acute motor effects of classical antipsychotics. The present study investigated if CBD would attenuate orofacial dyskinesia, oxidative stress and inflammatory changes induced by chronic administration of haloperidol in mice. Furthermore, we verified in vivo and in vitro (in primary microglial culture) whether these effects would be mediated by PPARγ receptors. The results showed that the male Swiss mice treated daily for 21 days with haloperidol develop orofacial dyskinesia. Daily CBD administration before each haloperidol injection prevented this effect. Mice treated with haloperidol showed an increase in microglial activation and inflammatory mediators in the striatum. These changes were also reduced by CBD. On the other hand, the levels of the anti-inflammatory cytokine IL-10 increased in the striatum of animals that received CBD and haloperidol. Regarding oxidative stress, haloperidol induced lipid peroxidation and reduced catalase activity. This latter effect was attenuated by CBD. The combination of CBD and haloperidol also increased PGC-1α mRNA expression, a co-activator of PPARγ receptors. Pretreatment with the PPARγ antagonist, GW9662, blocked the behavioural effect of CBD in our TD model. CBD also prevented LPS-stimulated microglial activation, an effect that was also antagonized by GW9662. In conclusion, our results suggest that CBD could prevent haloperidol-induced orofacial dyskinesia by activating PPARγ receptors and attenuating neuroinflammatory changes in the striatum.

Haplo-Insufficiency or Knockout of the Serotonin Transporter Does not Affect Heroin Self-Administration but Decreases BDNF in the Frontal Cortex

(1) Background: Drug addiction places a heavy burden on those affected by it but only a small percentage of individuals (~20%), regardless of their drug of abuse, go on to develop the compulsive behaviours that define drug addiction. Clinical studies have shown that genetic variations that reduce serotonin transporter (SERT) activity increase the vulnerability to developing a variety of psychiatric disorders such as depression, anxiety and drug addiction. (2) Methods: To investigate the influence of reduced SERT function in the laboratory, we studied the effects of heroin self-administration in a SERT knockout rat model. Groups of homozygous knockout (HOM), heterozygous (HET) or wild type (WT) animals completed a series of heroin self-administration experiments. In addition, quantitative reverse transcription polymerase chain reaction was used to measure relative abundance of brain derived neurotrophic factor (BDNF) transcripts of in the frontal cortex and striatum in animals that had previously self-administered heroin. (3) Results: There were no differences between the genotypes for acquisition, maintenance and progressive ratio responding for heroin self-administration. However, relative expression of total BDNF and the BDNF III and BDNF VI isoforms were significantly decreased in the frontal cortex of animals that had self-administered heroin for all genotypes, however, no differences in BDNF expression were found in RNA isolated from the striatum relative to untreated control animals. (4) Conclusions: These data suggest that reduced SERT function does not augment the addictive properties of heroin and support the hypothesis that different classes of addictive substances act through different neurobiological pathways.

Tolfenamic Acid: A Modifier of the Tau Protein and its Role in Cognition and Tauopathy.

Tangles are deposits of hyperphosphorylated tau, which are found in multiple neurodegenerative disorders that are referred to as tauopathies, of which Alzheimer's disease (AD) is the most common. Tauopathies are clinically characterized by dementia and share common cortical lesions composed of aggregates of the protein tau. In this study, we explored the therapeutic potential of tolfenamic acid (TA), in modifying disease processes in a transgenic animal model that carries the human tau gene (hTau). Behavioral tests, Western blotting and Immunohistochemical analysis were used to demonstrate the efficacy of TA. Treatment of TA improved improving spatial learning deficits and memory impairments in young and aged hTau mice. Western blot analysis of the hTau protein revealed reductions in total tau as well as in sitespecific hyperphosphorylation of tau in response to TA administration. Immunohistochemical analysis for phosphorylated tau protein revealed reduced staining in the frontal cortex, hippocampus, and striatum in animals treated with TA. TA holds the potential as a disease-modifying agent for the treatment of tauopathies including AD.

Biochemical and histological changes produced by sweeteners and cytarabine in the brain of young rats.

The aim of this study was to evaluate the effect of splenda and stevia on dopamine and 5-HIAA levels, and some biomarkers of oxidative stress in the presence of cytarabine. Forty-eight young male Wistar rats each with a weight of 80 g (four weeks of age), distributed in six groups of eight animals each, were treated as follows: group 1, control (NaCl 0.9% vehicle); group 2, cytarabine (0.6 g/kg); group 3, stevia (0.6 g/kg); group 4, cytarabine + stevia; group 5, splenda; and group 6, cytarabine + splenda. Cytarabine was given intravenously (IV) while stevia and splenda were administered orally for five days, using orogastric tube. At the end of treatment, the animals were sacrificed and glucose levels in blood were measured. The brains were dissected for histological analysis and homogenated to measure levels of dopamine, lipid peroxidation (TBARS), serotonin metabolite (5-HIAA), Na+, K+ ATPase activity, and glutathione (GSH), using validated methods. Sweeteners increased the glucose in animals that received cytarabine. Dopamine increased in cortex and decreased in striatum of animals that received stevia alone and combined with cytarabine. 5-HIAA decreased in striatum and cerebellum/medulla oblongata of animals that received sweeteners and cytarabine alone or combined. GSH increased in animals that received sweeteners and decreased with cytarabine. Lipoperoxidation decreased in groups that received sweeteners and cytarabine. Histopathological changes revealed marked degeneration of neuronal cells in animals treated with cytarabine. These results show that sweeteners as stevia or splenda may lead to the onset of unfavorable changes in dopamine and 5-HIAA. Antioxidant effects may be involved. Besides, histological changes revealed marked lesions of neuronal cells in experimental animals treated with cytarabine.

Concise Review: Innate and Adaptive Immune Recognition of Allogeneic and Xenogeneic Cell Transplants in the Central Nervous System.

Over the last 30 years, numerous allogeneic and xenogeneic cell grafts have been transplanted into the central nervous system (CNS) of mice and men in an attempt to cure neurological diseases. In the early studies, human or porcine embryonic neural cells were grafted in the striatum of animals or patients in an attempt to replace lost neurons. Although the immune‐privileged status of the brain as a recipient organ was widely accepted, it rapidly became evident that CNS‐grafted allogeneic and xenogeneic cells could be recognized and rejected by the immune system, resulting in poor neural graft survival and limited functional recovery. Since then, the CNS transplantation field has witnessed a sharp rise in the number of studies in which allogeneic and xenogeneic neural or mesenchymal stem cells (NSCs or MSCs, respectively) are transplanted, predominantly aiming at providing trophic stimulation and promoting endogenous repair of the brain. Interestingly, in many recent NSC and MSC‐based publications functional improvement was used as the principal measure to evaluate the success of cell transplantation, while the fate of transplanted cells remained largely unreported. In this review, we first attempt to understand why primary neural cell isolates were largely substituted for NSCs and MSCs in cell grafting studies. Next, we review the current knowledge on the immune mechanisms involved in the recognition and rejection of allogeneic and xenogeneic cellular grafts in the CNS. Finally, we propose strategies to reduce graft immunogenicity and to improve graft survival in order to design improved cell‐based CNS therapies. Stem Cells Translational Medicine 2017;6:1434–1441

Longitudinal Motor and Behavioral Assessment of Blood–Brain Barrier Opening with Transcranial Focused Ultrasound

Focused ultrasound (FUS), in combination with microbubbles, has been found to open the blood–brain barrier (BBB) non-invasively. When this technique is used for drug delivery, repeated drug administration and BBB opening are likely required. Therefore, it is worth investigating the long-term effects of FUS-induced BBB opening. In this study, we focused on the assessment of potential behavior changes in mice that could be attributed to repeated BBB opening for up to 6 months. The striatum of animals was unilaterally sonicated either monthly or biweekly throughout the monitoring period. Behavioral assessments were conducted using open-field and rotarod performance tests. Upon completion of each sonication, mice underwent magnetic resonance imaging (MRI) to confirm and assess the volume of the BBB opening. No differences in locomotor activity between BBB-opened and control groups in both biweekly and monthly treated mice were evident up to 6 months. Similarly, there was no affinity for a particular turn angle in the sonicated mice compared with the control animals. However, the positive control group exhibited a significant decrease in locomotor activity, as well as rotation ipsilateral to the sonicated hemisphere. Our results based on the assessment using open-field and rotarod tests indicated that repeated opening of the BBB in the striatum using FUS in conjunction with microbubbles over a period of 6 mo and under the parameters used here did not cause motor impairment, behavioral changes or morphologic alterations. This reinforces the tolerability of repeated and long-term drug delivery using FUS-induced BBB opening.

Morphological Changes within the Rat Lateral Ventricle after the Administration of Proteasome Inhibitors.

The broad variety of substances that inhibit the action of the ubiquitin-proteasome system (UPS)—known as proteasome inhibitors—have been used extensively in previous studies, and they are currently frequently proposed as a novel form of cancer treatment and as a protective factor in intracerebral hemorrhage treatment. The experimental data on the safest route of proteasome inhibitor administration, their associated side effects, and the possible ways of minimizing these effects have recently become a very important topic. The aim of our present study was to determine the effects of administering of MG-132, lactacystin and epoxomicin, compounds belonging to three different classes of proteasome inhibitors, on the ependymal walls of the lateral ventricle. Observations were made 2 and 8 weeks after the intraventricular administration of the studied substances dissolved in dimethyl sulfoxide (DMSO) into the lateral ventricle of adult Wistar rats. Qualitative and quantitative analysis of brain sections stained with histochemical and inmmunofluorescence techniques showed that the administration of proteasome inhibitors caused a partial occlusion of the injected ventricle in all of the studied animals. The occlusion was due to ependymal cells damage and subsequent ependymal discontinuity, which caused direct contact between the striatum and the lateral nuclei of the septum, mononuclear cell infiltration and the formation of a glial scar between these structures (with the activation of astroglia, microglia and oligodendroglia). Morphologically, the ubiquitin-positive aggregates corresponded to aggresomes, indicating impaired activity of the UPS and the accumulation and aggregation of ubiquitinated proteins that coincided with the occurrence of glial scars. The most significant changes were observed in the wall covering the striatum in animals that were administered epoxomicin, and milder changes were observed in animals administered lactacystin and MG-132. Interestingly, DMSO administration also caused damage to some of the ependymal cells, but the aggresome-like structures were not formed. Our results indicate that all of the studied classes of proteasome inhibitors are detrimental to ependymal cells to some extent, and may cause severe changes in the ventricular system. The safety implications of their usage in therapeutic strategies to attenuate intracerebral hemorrhagic injury and in brain cancer treatment will require further studies.

Moderate-Intensity Physical Exercise Protects Against Experimental 6-Hydroxydopamine-Induced Hemiparkinsonism Through Nrf2-Antioxidant Response Element Pathway.

Exercise improves the motor symptoms of patients with Parkinson disease in a palliative manner. Existing evidence demonstrates that exercise induces neuroprotection based on the neurotrophic properties. We investigated the effect of exercise on mitochondrial physiology and oxidative stress in an animal model of hemiparkinsonism. C57BL/6 mice completed a 6-week exercise program on a treadmill. We injected 6-hydroxydopamine (6-OHDA; 4 μg/2 μl) into the midstriatum. The animals progressively developed bradykinesia and R(-)-apomorphine-induced rotations that were attenuated by exercise. Transcriptional activation of protective genes is mediated by the antioxidant response element (ARE). Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) binds to ARE. We investigated the Nrf2-ARE pathway in the striatum of animals. Exercise protected 6-OHDA-induced loss of tyrosine hydroxylase immunolabeling and activated the Nrf2-ARE pathway in the nigrostriatal pathway. Exercise stimulated mitochondrial biogenesis in the striatum of animals that was more resistant to oxidant 6-OHDA and nitric oxide donor (±)-S-nitroso-N-acetylpenicillamine. In mice, exercise activated Nrf2-ARE signaling in the nigrostriatal pathway that was protective against the development of hemiparkinsonism.

Distinct patterns of outcome valuation and amygdala-prefrontal cortex synaptic remodeling in adolescence and adulthood.

Adolescent behavior is typified by increased risk-taking, reward- and novelty-seeking, as well as an augmented need for social and environmental stimulation. This behavioral phenotype may result from alterations in outcome valuation or reward learning. In the present set of experiments, we directly compared adult and adolescent animals on tasks measuring both of these processes. Additionally, we examined developmental differences in dopamine D1-like receptor (D1R), dopamine D2-like receptor (D2R), and polysialylated neural cell adhesion molecule (PSA-NCAM) expression in animals that were trained on an effortful reward valuation task, given that these proteins play an important role in the functional development of the amygdala-prefrontocortical (PFC) circuit and mesocorticolimbic dopamine system. We found that adolescent animals were not different from adults in appetitive associative learning, but exhibited distinct pattern of responses to differences in outcome values, which was paralleled by an enhanced motivation to invest effort to obtain larger rewards. There were no differences in D2 receptor expression, but D1 receptor expression was significantly reduced in the striatum of animals that had experiences with reward learning during adolescence compared to animals that went through the same experiences in adulthood. We observed increased levels of PSA-NCAM expression in both PFC and amygdala of late adolescents compared to adults that were previously trained on an effortful reward valuation task. PSA-NCAM levels in PFC were strongly and positively associated with high effort/reward (HER) choices in adolescents, but not in adult animals. Increased levels of PSA-NCAM expression in adolescents may index increased structural plasticity and represent a neural correlate of a reward sensitive endophenotype.

Antioxidant defense in the rat brain cortex, cerebellum, hippocampus, and striatum and its alterations during portacaval shunting

Portacaval anastomoses spontaneously appear during liver insufficiency and lead to chronic hyperammonemia and hepatic encephalopathy. Ammonium induces oxidative stress in the brain. Here, we compared the state of the antioxidant system in different rat brain areas and studied the manner in which it is affected by portacaval shunting. At 4 weeks after the surgical operation, we measured the activities of catalase, Cu,Zn-superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione transferase in cytoplasm and content of oxidized proteins in mitochondria of the neocortex, cerebellum, hippocampus, and striatum. All four brain regions differed according to the ammonium content and activity of each antioxidant enzyme. The activity of glutathione peroxidase decreased as compared to the control only in the cerebellum and striatum of animals with portacaval shunt. After portacaval shunting, the activities of catalase, Cu,Zn-superoxide dismutase, glutathione peroxidase, and glutathione reductase did not differ from the control in all the brain regions we studied. An inverse correlation between the content of oxidized proteins and activity of glutathione transferase suggests that the diminished activity of glutathione peroxidase in the cerebellum and striatum, but not other antioxidant enzymes and other brain regions, may play a role in the pathogenesis of hepatic encephalopathy.

Aberrant restoration of spines and their synapses in L-DOPA-induced dyskinesia: involvement of corticostriatal but not thalamostriatal synapses.

We examined the structural plasticity of excitatory synapses from corticostriatal and thalamostriatal pathways and their postsynaptic targets in adult Sprague-Dawley rats to understand how these striatal circuits change in l-DOPA-induced dyskinesias (LIDs). We present here detailed electron and light microscopic analyses that provide new insight into the nature of the structural and synaptic remodeling of medium spiny neurons in response to LIDs. Numerous studies have implicated enhanced glutamate signaling and persistent long-term potentiation as central to the behavioral sensitization phenomenon of LIDs. Moreover, experience-dependent alterations in behavior are thought to involve structural modifications, specifically alterations in patterns of synaptic connectivity. Thus, we hypothesized that in the striatum of rats with LIDs, one of two major glutamatergic pathways would form new or altered contacts, especially onto the spines of medium spiny neuron (MSNs). Our data provide compelling evidence for a dramatic rewiring of the striatum of dyskinetic rats and that this rewiring involves corticostriatal but not thalamostriatal contacts onto MSNs. There is a dramatic increase in corticostriatal contacts onto spines and dendrites that appear to be directly linked to dyskinetic behaviors, since they were not seen in the striatum of animals that did not develop dyskinesia. There is also an aberrant increase in spines receiving more than one excitatory contact(i.e., multisynaptic spines) in the dyskinetic animals compared with the 6-hydroxydopamine-treated and control rats. Such alterations could substantially impair the ability of striatal neurons to gate cortically driven signals and contribute to the loss of bidirectional synaptic plasticity.

Heat shock transcription factor-1 suppresses apoptotic cell death and ROS generation in 3-nitropropionic acid-stimulated striatal cells

Striatal neuronal cell death is one of the pathological features of Huntington's disease (HD). Overexpression of some heat shock proteins (HSPs) has been reported to suppress the aggregate formation of mutant huntingtin and concurrent cell death. Heat shock transcription factor-1 (HSF 1), a major transcription factor of HSPs, has also been reported to be increased in HD models. However, the exact role of HSF 1 in the pathogenesis of HD has not been clearly elucidated. 3-Nitropropionic acid (3NP), an irreversible inhibitor of the mitochondrial complex II, induces selective damage to the striatum in animals and produces clinical features of HD. To investigate roles of HSF 1 on 3NP-induced oxidative stress, HSF 1 was transiently overexpressed in striatal cells. Expression of HSF 1 significantly attenuated 3NP-induced apoptotic striatal cell death and resulted in increased expression of HSP 70. Furthermore, expression of HSF 1 significantly attenuated 3NP-induced intracellular reactive oxygen species (ROS) generation. Taken together, the present study clearly demonstrates that HSF 1 attenuates 3NP-induced apoptotic striatal cell death and ROS generation, possibly through HSP70 expression, suggesting that HSF 1 might be a valuable therapeutic target in the treatment of HD.

Folic Acid Prevents Behavioral Impairment and Na+,K+-ATPase Inhibition Caused by Neonatal Hypoxia–Ischemia

Folic acid plays an important role in neuroplasticity and acts as a neuroprotective agent, as observed in experimental brain ischemia studies. The aim of this study was to investigate the effects of folic acid on locomotor activity, aversive memory and Na(+),K(+)-ATPase activity in the frontal cortex and striatum in animals subjected to neonatal hypoxia-ischemia (HI). Wistar rats of both sexes at postnatal day 7 underwent HI procedure and were treated with intraperitoneal injections of folic acid (0.011 μmol/g body weight) once a day, until the 30th postnatal day. Starting on the day after, behavioral assessment was run in the open field and in the inhibitory avoidance task. Animals were sacrificed by decapitation 24 h after testing and striatum and frontal cortex were dissected out for Na(+),K(+)-ATPase activity analysis. Results show anxiogenic effect in the open field and an impairment of aversive memory in the inhibitory avoidance test in HI rats; folic acid treatment prevented both behavioral effects. A decreased Na(+),K(+)-ATPase activity in striatum, both ipsilateral and contralateral to ischemia, was identified after HI; a total recovery was observed in animals treated with folic acid. A partial recovery of Na(+),K(+)-ATPase activity was yet seen in frontal cortex of HI animals receiving folic acid supplementation. Presented results support that folic acid treatment prevents memory deficit and anxiety-like behavior, as well as prevents Na(+),K(+)-ATPase inhibition in the striatum and frontal cortex caused by neonatal hypoxia-ischemia.

MALDI Imaging Mass Spectrometry of Neuropeptides in Parkinson's Disease

MALDI imaging mass spectrometry (IMS) is a powerful approach that facilitates the spatial analysis of molecular species in biological tissue samples2 (Fig.1). A 12 μm thin tissue section is covered with a MALDI matrix, which facilitates desorption and ionization of intact peptides and proteins that can be detected with a mass analyzer, typically using a MALDI TOF/TOF mass spectrometer. Generally hundreds of peaks can be assessed in a single rat brain tissue section. In contrast to commonly used imaging techniques, this approach does not require prior knowledge of the molecules of interest and allows for unsupervised and comprehensive analysis of multiple molecular species while maintaining high molecular specificity and sensitivity2. Here we describe a MALDI IMS based approach for elucidating region-specific distribution profiles of neuropeptides in the rat brain of an animal model Parkinson's disease (PD). PD is a common neurodegenerative disease with a prevalence of 1% for people over 65 of age3,4. The most common symptomatic treatment is based on dopamine replacement using L-DOPA5. However this is accompanied by severe side effects including involuntary abnormal movements, termed L-DOPA-induced dyskinesias (LID)1,3,6. One of the most prominent molecular change in LID is an upregulation of the opioid precursor prodynorphin mRNA7. The dynorphin peptides modulate neurotransmission in brain areas that are essentially involved in movement control7,8. However, to date the exact opioid peptides that originate from processing of the neuropeptide precursor have not been characterized. Therefore, we utilized MALDI IMS in an animal model of experimental Parkinson's disease and L-DOPA induced dyskinesia. MALDI imaging mass spectrometry proved to be particularly advantageous with respect to neuropeptide characterization, since commonly used antibody based approaches targets known peptide sequences and previously observed post-translational modifications. By contrast MALDI IMS can unravel novel peptide processing products and thus reveal new molecular mechanisms of neuropeptide modulation of neuronal transmission. While the absolute amount of neuropeptides cannot be determined by MALDI IMS, the relative abundance of peptide ions can be delineated from the mass spectra, giving insights about changing levels in health and disease. In the examples presented here, the peak intensities of dynorphin B, alpha-neoendorphin and substance P were found to be significantly increased in the dorsolateral, but not the dorsomedial, striatum of animals with severe dyskinesia involving facial, trunk and orolingual muscles (Fig. 5). Furthermore, MALDI IMS revealed a correlation between dyskinesia severity and levels of des-tyrosine alpha-neoendorphin, representing a previously unknown mechanism of functional inactivation of dynorphins in the striatum as the removal of N-terminal tyrosine reduces the dynorphin's opioid-receptor binding capacity9. This is the first study on neuropeptide characterization in LID using MALDI IMS and the results highlight the potential of the technique for application in all fields of biomedical research.

MALDI imaging mass spectrometry of neuropeptides in Parkinson's disease.

MALDI imaging mass spectrometry (IMS) is a powerful approach that facilitates the spatial analysis of molecular species in biological tissue samples2 (Fig.1). A 12 μm thin tissue section is covered with a MALDI matrix, which facilitates desorption and ionization of intact peptides and proteins that can be detected with a mass analyzer, typically using a MALDI TOF/TOF mass spectrometer. Generally hundreds of peaks can be assessed in a single rat brain tissue section. In contrast to commonly used imaging techniques, this approach does not require prior knowledge of the molecules of interest and allows for unsupervised and comprehensive analysis of multiple molecular species while maintaining high molecular specificity and sensitivity2. Here we describe a MALDI IMS based approach for elucidating region-specific distribution profiles of neuropeptides in the rat brain of an animal model Parkinson's disease (PD). PD is a common neurodegenerative disease with a prevalence of 1% for people over 65 of age3,4. The most common symptomatic treatment is based on dopamine replacement using L-DOPA5. However this is accompanied by severe side effects including involuntary abnormal movements, termed L-DOPA-induced dyskinesias (LID)1,3,6. One of the most prominent molecular change in LID is an upregulation of the opioid precursor prodynorphin mRNA7. The dynorphin peptides modulate neurotransmission in brain areas that are essentially involved in movement control7,8. However, to date the exact opioid peptides that originate from processing of the neuropeptide precursor have not been characterized. Therefore, we utilized MALDI IMS in an animal model of experimental Parkinson's disease and L-DOPA induced dyskinesia. MALDI imaging mass spectrometry proved to be particularly advantageous with respect to neuropeptide characterization, since commonly used antibody based approaches targets known peptide sequences and previously observed post-translational modifications. By contrast MALDI IMS can unravel novel peptide processing products and thus reveal new molecular mechanisms of neuropeptide modulation of neuronal transmission. While the absolute amount of neuropeptides cannot be determined by MALDI IMS, the relative abundance of peptide ions can be delineated from the mass spectra, giving insights about changing levels in health and disease. In the examples presented here, the peak intensities of dynorphin B, alpha-neoendorphin and substance P were found to be significantly increased in the dorsolateral, but not the dorsomedial, striatum of animals with severe dyskinesia involving facial, trunk and orolingual muscles (Fig. 5). Furthermore, MALDI IMS revealed a correlation between dyskinesia severity and levels of des-tyrosine alpha-neoendorphin, representing a previously unknown mechanism of functional inactivation of dynorphins in the striatum as the removal of N-terminal tyrosine reduces the dynorphin's opioid-receptor binding capacity9. This is the first study on neuropeptide characterization in LID using MALDI IMS and the results highlight the potential of the technique for application in all fields of biomedical research.

Effects of Kangpa bolus on behaviors and dopamine concentration of striatum in Parkinson's disease model animals

Objective To investigate the effects of Kangpa bolus on behaviors, dopamine and its metabolites of striatum in animals with Parkinson' s disease (PD). Methods The mice models of muscle tremor and rigor were established to observe the antagonism of Kangpa bolus. Step-down and step-through tests were used to evaluate the effects of Kangpa bolus on learning and memory function in mice. The rat model of PD was established to observe the effects of Kangpa bolus on rotation behaviors. The contents of DA and homovanillic acid( HVA) in the injured side of striatum were detected by ELISA. Results Compared with model group(723. 1 ±79.3) s,the duration of tremor in mice shortened significantly (P < 0. 01) in Kangpa bolus high dose and middle dose group ((548.0±27.0)s,(590.9 ±28.7)s). Compared with model group(3194.5 ±251.7)s,the duration of rigor in mice shortened significantly(P<0.01) in Kangpa bolus all dose group((2300.1 ±352.5)s,(2478.2 ±276.6)s, (2559.3 ±207.6) s). In step-down test, compared with model group (3. 10 ±0.74), the number of errors decreased significantly(P<0.01) in Kangpa bolus high dose and middle dose group (1.60 ±0. 97,1. 80 ±0.63). In step-through test, compared with model group( 2.30 ± 0. 68), the number of errors decreased significantly (P < 0.01) in Kangpa bolus high dose and middle dose group(0.80 ±0.79,1.10 ±0.74). Compared with model group (340.6 ±18.8) , the number of rotations of PD rats in thirty minutes reduced significantly (P< 0.01) in Kangpa bolus high dose and middle dose group(286.5 ± 12.1,296.6 ± 12.7) after three weeks treatment. Compared with model group(9.43 ±1.79,0. 87 ±0.12) nmol/L,the contents of DA and HVA in the injured side of striatum increased significantly(P<0. 01 ) in Kangpa bolus high dose( 18. 9 ±4. 01,1. 50 ± 1. 39) nmol/L and middle dose group (17.3±3.01,1.39±0.53)nmol/L Conclusion Kangpa bolus has some therapeutic effects on the animals of PD. Key words: Parkinson disease; Kangpa bolus; Step-down test; Step-through test; Rotation test

Cellular immune response to intrastriatally implanted allogeneic bone marrow stromal cells in a rat model of Parkinson's disease.

BackgroundMarrow stromal cells (MSC), the non-hematopoietic precursor cells in bone marrow, are being investigated for therapeutic potential in CNS disorders. Although in vitro studies have suggested that MSC may be immunologically inert, their immunogenicity following transplantation into allogeneic recipients is unclear. The primary objective of this study was to investigate the cellular immune response to MSC injected into the striatum of allogeneic recipients (6-hydroxydopamine [6-OHDA]-hemilesioned rats, an animal model of Parkinson's disease [PD]), and the secondary objective was to determine the ability of these cells to prevent nigrostriatal dopamine depletion and associated motor deficits in these animals.Methods5-Bromo-2-deoxyuridine (BrdU) – labeled MSC from two allogeneic sources (Wistar and ACI rats) were implanted into the striatum of adult Wistar rats at the same time as 6-OHDA was administered into the substantia nigra. Behavioral tests were administered one to two weeks before and 16–20 days after 6-OHDA lesioning and MSC transplantation. Immunocytochemical staining for T helper and T cytotoxic lymphocytes, microglia/macrophages, and major histocompatibility class I and II antigens was performed on post-transplantation days 22–24. MSC were detected with an anti-BrdU antibody.ResultsTissue injury due to the transplantation procedure produced a localized cellular immune response. Unexpectedly, both sources of allogeneic MSC generated robust cellular immune responses in the host striatum; the extent of this response was similar in the two allograft systems. Despite these immune responses, BrdU+ cells (presumptive MSC) remained in the striatum of all animals that received MSC. The numbers of remaining MSC tended to be increased (p = 0.055) in rats receiving Wistar MSC versus those receiving ACI MSC. MSC administration did not prevent behavioral deficits or dopamine depletion in the 6-OHDA-lesioned animals.ConclusionMSC, when implanted into the striatum of allogeneic animals, provoke a marked immune response which is not sufficient to clear these cells by 22–24 days post-transplantation. In the experimental paradigm in this study, MSC did not prevent nigrostriatal dopamine depletion and its associated behavioral deficits. Additional studies are indicated to clarify the effects of this immune response on MSC survival and function before initiating trials with these cells in patients with PD or other neurodegenerative disorders.

Synthèse de monoamines par des neurones non-monoaminergiques. Illusion ou réalité ?

In contrast to monoaminergic (MA-ergic) neurons possessing the whole set of the enzymes for MA synthesis from the precursor amino-acid, some, mostly peptidergic, neurons co-express only one of the enzymes of monoamine synthesis. They are widely distributed in the brain, being particularly numerous in ontogenesis and, in adulthood, under certain physiological conditions. Most monoenzymatic neurons possess one of the enzymes for dopamine (DA) synthesis, tyrosine hydroxylase (TH) or aromatic L-amino acid decarboxylase (AADC). TH and AADC are enzymatically active in a substantial number of monoenzymatic neurons, where they are capable of converting L-tyrosine to L-3,4-dihydroxy-phenylalanine (L-DOPA) and L-DOPA to dopamine (DA) (or 5-hydroxy-tryptophan, 5-HTP to serotonin), respectively. According to our data L-DOPA synthesized in monoenzymatic TH-neurons is released and taken up by monoenzymatic AADC-neurons for DA synthesis. Moreover, L-DOPA captured by dopaminergic neurons and serotoninergic neurons serves to stimulate dopamine synthesis in the former and to start DA synthesis in the latter. Cooperative synthesis of MAs is considered as a compensatory reaction under a failure of MA-ergic neurons, e.g. in neurodegenerative diseases like hyperprolactinemia and Parkinson's disease, which are developed primarily because of degeneration of DA-ergic neurons of the tuberoinfundibular system and the nigrostriatal system, respectively. Noteworthy, the neurotoxin-induced increase of prolactin secretion returns with time to a normal level due to the stimulation of DA synthesis by the tuberoinfundibular most probably monoenzymatic neurons. The same compensatory mechanism is supposed to be used under the failure of the nigrostriatal DA-ergic system that is manifested by an increased number of monoenzymatic neurons in the striatum of animals with neurotoxin-induced parkinsonism and in humans with Parkinson's disease. Expression of the enzymes of MA synthesis in non-monoaminergic neurons is controlled by intercellular signals such as classical neurotransmitters (catecholamines), etc. Thus, a substantial number of brain neurons express partly the monoaminergic phenotype, namely individual complementary enzymes of MA synthesis, serving to produce MAs in cooperation, which is considered as a compensatory reaction under the failure of MA-ergic neurons.

Whole body hyperthermia reduces oxidative stress in the striatum of rats in an animal model of mitochondrial toxicity with 3-nitropropionic acid

Purpose: The goal of this study was to determine whether whole body hyperthermia (WBH) could reduce oxidative stress in the striatum produced by 3-nitropropionic acid (3-NP), a mitochondrial toxin that irreversibly inhibits succinate dehydrogenase (SDH), causing impairment of energy metabolism, oxidative stress and a selective degeneration of striatal cells.Methods: Rats were subjected to WBH (42°C) or normothermia control conditions for 30 min and then treated with 3-NP. Striatum samples were processed and the levels of protein carbonyl groups, biogenic amines, Hsp72 and salicylate hydroxylation (to probe the hydroxyl radical (OH•) intervention) were determined.Results: WBH significantly reduced oxidative stress in the striatum of animals treated with 3-NP, as judged by reductions in protein carbonyl and salicylate hydroxylation derivative levels, whereas striatal Hsp72 expression was significantly increased. The groups treated with 3-NP presented an increased in the dopamine (DA) derivatives 2,3-dihydroxyphenylacetic acid (DOPAC) and norepinephrine (NE) concentration, whereas the striatal relation DOPAC/DA concentration indicate a reduced dopamine turnover.Conclusions: These studies show, for the first time, that a heat shock pretreatment can ameliorate the oxidative stress produced by a metabolic toxin (3-NP) capable of impairing energy supply and produce selective striatal degeneration. These data contribute to a better understanding of the potential for thermal stress to modulate the type of oxidative stress usually present in neurodegenerative disorders associated with metabolic defects.

Catalytic metalloporphyrin protects against MPTP-induced Parkinson's disease in mice

Objective:To observe the effects of manganese(Ⅲ)meso-tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin(MnTDM)in treatment of early Parkinson's disease(PD)mouse model induced by subcutaneous injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)and to discuss its possible mechanism.Methods:Forty male C57BL/6 mice were evenly randomized into 4 groups:MPTP model group(subcutaneous injection of 25 mg/kg MPTP for 3 days).MnTDM +MPTP group(15 mg/kg MnTDM was subcutaneously injected 1 h before MPTP injection).MnTDM control group,and normal saline group.Performance of animals in the pole and swimming test was observed 3 days after the last injection.Levels of dopamine(DA)and its metabolites(3,4-dihydroxyphenylacetic acid [DOPAC] and homovanillic acid [HVA])in the striatum of animals were measured by high-performance liquid chromatography with an electrochemical detector(HPLC-ECD).Thiobarbituric acid(TBA)method was used to examine the levels of malondialdehyde(MDA).Results:Acute injection of MPTP could be used for establishment of PD model.The striatal levels of DA,DOPAC and HVA in MPTP group were significantly lower(P0.01)and the striatal level of MDA was significantly higher(P0.05)than those of the control group.MPTP had no obvious effect on the behavioral performance of the animals in a short term.MnTDM could partly inhibit the above effects of MPTP.Compared with MPTP group,MnTDM+MPTP group had significantly higher DA,DOPAC,and HVA levels and significantly lower MDA level(all P0.05).There was no significant difference in the behavioral indices of animals between the 4 groups.Conclusion:MnTDM can inhibit lipid peroxidation and promote DA production;it has preventive and therapeutic effects on MPTP-induced PD.