Alterations in brain amino acid metabolism and inhibitory effects on PKC are possibly correlated with anticonvulsant effects of the isomeric mixture of α- and ß-amyrin from Protium heptaphyllum.

CONTEXT: α- and ß-Amyrin (AMY) from Protium heptaphyllum (Aubl) March (Burseraceae) is found in Brazil and used in diverse inflammation-related diseases. This species presents a central action, as previously described. OBJECTIVE: The objectives were to evaluate the anticonvulsant effect of AMY in mice and to verify the mechanism of action. MATERIAL AND METHODS: Seizures were induced by pentylenetetrazole followed by acute or subchronic treatments (5-25 mg/kg, p.o. and i.p.) and determination of brain amino acids (10 and 25 mg/kg, i.p., 7 d). RESULTS: In the acute treatment, AMY (10, 25, and 50 mg/kg, p.o.) increased the latency to the first convulsion (FC) by 30, 44, and 40% and time to death (TD) by 36, 52, and 42%, respectively. When administered intraperitoneally, the same doses increased FC by 62, 75, and 73% and TD by 76, 82, and 119%, respectively. Combined with polymixin or staurosporine, AMY (25 mg/kg, i.p.) increased TD by 61 and 63%, respectively, as related to each drug alone. When subchronically administered (25 and 50 mg/kg, i.p.) increased FC by 75 and 101% and TD by 86 and 124%, respectively. AMY increased taurine (116 and 76%) and tyrosine concentrations (135 and 110%) in basal ganglia and hippocampus, respectively, and decreased by 68, 65, and 62% glutamate, aspartate, and GABA in basal ganglia. CONCLUSION: Thus, the AMY anticonvulsant activity is related to the GABAergic system and may be linked to the inhibition of the signaling cascade of PKC as well as to alterations in amino acids metabolism.

Role of enteric glia and microbiota-gut-brain axis in parkinson disease pathogenesis.

The microbiota-gut-brain axis or simple gut-brain axis (GBA) is a complex and interactive bidirectional communication network linking the gut to the brain. Alterations in the composition of the gut microbiome have been linked to GBA dysfunction, central nervous system (CNS) inflammation, and dopaminergic degeneration, as those occurring in Parkinson's disease (PD). Besides inflammation, the activation of brain microglia is known to play a central role in the damage of dopaminergic neurons. Inflammation is attributed to the toxic effect of aggregated α-synuclein, in the brain of PD patients. It has been suggested that the α-synuclein misfolding might begin in the gut and spread "prion-like", via the vagus nerve into the lower brainstem and ultimately to the midbrain, known as the Braak hypothesis. In this review, we discuss how the microbiota-gut-brain axis and environmental influences interact with the immune system to promote a pro-inflammatory state that is involved in the initiation and progression of misfolded α-synuclein proteins and the beginning of the early non-motor symptoms of PD. Furthermore, we describe a speculative bidirectional model that explains how the enteric glia is involved in the initiation and spreading of inflammation, epithelial barrier disruption, and α-synuclein misfolding, finally reaching the central nervous system and contributing to neuroinflammatory processes involved with the initial non-motor symptoms of PD.

Gut-microbiome-brain axis: the crosstalk between the vagus nerve, alpha-synuclein and the brain in Parkinson's disease.

This critical review of the literature shows that there is a close link between the microbiome, the gut, and the brain in Parkinson's disease. The vagus nerve, the main component of the parasympathetic nervous system, is involved in the regulation of immune response, digestion, heart rate, and control of mood. It can detect microbiota metabolites through its afferents, transferring this gut information to the central nervous system. Preclinical and clinical studies have shown the important role played by the gut microbiome and gut-related factors in disease development and progression, as well as treatment responses. These findings suggest that the gut microbiome may be a valuable target for new therapeutic strategies for Parkinson's disease. More studies are needed to better understand the underlying biology and how this axis can be modulated for the patient's benefit.

Anticonvulsant effects of agomelatine in mice.

Agomelatine is a potent MT1 and MT2 melatonin receptor agonist and a 5-HT2C serotonin receptor antagonist. We analyzed whether agomelatine has anticonvulsant properties. The anticonvulsant activity of agomelatine (25, 50 or 75 mg/kg, i.p.) was evaluated in mouse models of pentylenetetrazole (PTZ-85 mg/kg, i.p.), pilocarpine (400mg/kg, i.p.), picrotoxin (7 mg/kg, i.p.), strychnine (75 mg/kg, i.p.) or electroshock-induced convulsions. In the PTZ-induced seizure model, agomelatine (at 25 or 50mg/kg) showed a significant increase in latency to convulsion, and agomelatine (at 50 or 75 mg/kg) also increased significantly time until death. In the pilocarpine-induced seizure model, only agomelatine in high doses (75 mg/kg) showed a significant increase in latency to convulsions and in time until death. In the strychnine-, electroshock- and picrotoxin-induced seizure models, agomelatine caused no significant alterations in latency to convulsions and in time until death when compared to controls. Our results suggest that agomelatine has anticonvulsant activity shown in PTZ- or pilocarpine-induced seizure models.

Cannabis sativa and Cannabidiol: A Therapeutic Strategy for the Treatment of Neurodegenerative Diseases?

This work is a literature review, presenting the current state of the use of cannabinoids on neurodegenerative diseases. The emphasis is on Parkinson's (PD) and Alzheimer's (AD) diseases, the two most prevalent neurological diseases. The review goes from Cannabis sativa and its hundreds of bioactive compounds to Δ9-tetrahydrocannabinol (THC) and mainly cannabidiol (CBD) and their interactions with the endocannabinoid receptors (CB1 and CB2). CBD molecular targets were also focused on to explain its neuroprotective action mechanism on neurodegenerative diseases. Although THC is the main psychoactive component of C. sativa, and it may induce transient psychosis-like symptoms, growing evidence suggests that CBD may have protective effects against the psychotomimetic effects of THC and therapeutic properties. Furthermore, a great number of recent works on the neuroprotective and anti-inflammatory CBD effects and its molecular targets are also reviewed. We analyzed CBD actions in preclinical and in clinical trials, conducted with PD and AD patients. Although the data on preclinical assays are more convincing, the same is not true with the clinical data. Despite the consensus among researchers on the potential of CBD as a neuroprotective agent, larger and well-designed randomized clinical trials will be necessary to gather conclusive results concerning the use of CBD as a therapeutic strategy for the treatment of diseases such as PD and AD.

The Protein-Rich Fraction from Spirulina platensis Exerts Neuroprotection in Hemiparkinsonian Rats by Decreasing Brain Inflammatory-Related Enzymes and Glial Fibrillary Acidic Protein Expressions.

Spirulina platensis is a cyanobacterium with high protein content and presenting neuroprotective effects. Now, we studied a protein-enriched fraction (SPF), on behavior, neurochemical and immunohistochemical (IHC) assays in hemiparkinsonian rats, distributed into the groups: SO (sham-operated), 6-hydroxydopamine (6-OHDA), and 6-OHDA (treated with SPF, 5 and 10 mg/kg, p.o., 15 days). Afterward, animals were subjected to behavioral tests and euthanized, and brain areas used for neurochemical and IHC assays. SPF partly reversed the changes in the apomorphine-induced rotations, open field and forced swim tests, and also the decrease in striatal dopamine and 3,4-dihydroxyphenylacetic acid contents seen in hemiparkinsonian rats. Furthermore, SPF reduced brain oxidative stress and increased striatal expressions of tyrosine hydroxylase and dopamine transporter and significantly reduced hippocampal inducible nitric oxide synthase, cyclooxygenase-2 and glial fibrillary acidic protein expressions. The data suggest that the protein fraction from S. platensis, through its brain anti-inflammatory and antioxidative actions, exerts neuroprotective effects that could benefit patients affected by neurodegenerative diseases, like Parkinson's disease.

B vitamins attenuate haloperidol-induced orofacial dyskinesia in rats: possible involvement of antioxidant mechanisms.

Tardive dyskinesia (TD) is a serious motor disorder related to antipsychotic therapy, whose pathophysiology is associated to oxidative stress. Treatments that maintain antipsychotic efficacy while reducing TD risk are awaited. Haloperidol (HAL), a typical antipsychotic, is used as a putative murine model of TD. Here, we evaluated the protective role of vitamins B1, B6, and B12 alone or in combination (vitamin B cocktail) in preventing the HAL-induced orofacial dyskinesia (OD), based on their antioxidant properties. HAL (1 mg/kg) administered intraperitoneally to Wistar rats for 21 days caused OD and increased catalepsy time. The daily administration of B vitamins (B1 : B6 : B12 at 60 : 60 : 0.6 mg/kg) alone or the vitamin B cocktail, along with HAL, prevented the development of OD. Catalepsy time reduced in all groups treated with B vitamins, but to a lesser extent than OD. The participation of oxidative stress was assessed by the determination of reduced glutathione (GSH) levels and lipid peroxide formation in the striatum. HAL significantly decreased GSH levels and enhanced lipid peroxidation, whereas B1, B12, and vitamin B cocktail prevented the decrease in GSH levels. All groups treated with B vitamins presented a decrease in lipid peroxide formation. The data suggest a promising role for B vitamins in the prevention of OD.

Arthrospira (Spirulina) platensis Attenuates Dextran Sulfate Sodium-induced Colitis in Mice by Suppressing Key Pro-inflammatory Cytokines.

Background/Aims: Therapies aimed at modulating cytokines have been used to treat inflammatory illnesses, such as inflammatory bowel disease. On the other hand, patients may become intolerant, refractory, or present with several side effects. Arthrospira (Spirulina) platensis (SPI) is a blue-green microalga with bioactive molecules that have been evaluated to treat inflammatory diseases. On the other hand, few studies have examined their effects on the production of specific cytokines and the intestinal architecture in dextran sulfate sodium (DSS)-induced colitis. Therefore, this study examined the effects of a treatment using SPI in a murine model of intestinal inflammation. Methods: All mice (C57BL/6 male) were evaluated daily for their food and water intake, bodyweight variations, and clinical signs of disease. Colon inflammation was induced by exposure to DSS for 6 consecutive days. SPI was given orally at 50, 100, and 250 mg/kg/day. ELISA was performed to assess the production of cytokines. Myeloperoxidase and nitric oxide were also investigated. The level of microscopic damage was assessed by staining colon sections with hematoxylin and eosin. Results: SPI attenuated the DSS-induced inflammation, with improvements in the clinical signs and a decrease in the production of inflammatory cytokines, such as tumor necrosis factor-α and interferon-γ. In addition, particularly at 250 mg/kg, SPI attenuated the severity of colitis by modulating the level of mucosal and submucosal cell infiltration, which preserved the epithelial barrier. Conclusions: SPI may be an alternative source of bioactive molecules with immunomodulatory properties, and has great potential to be used in the treatment of inflammatory diseases.

The Wound Healing Property of N-Methyl-(2S,4R)-trans-4-Hydroxy-L-Proline from Sideroxylon obtusifolium is Related to its Anti-Inflammatory and Antioxidant Actions.

Wound healing involves the interaction of blood cells, proteins, proteases, growth factors, and extracellular matrix components. Inflammation is one of the first events occurring during this process. Previously, we showed that the N-Methyl-(2S,4R)-trans-4-Hydroxy-L-Proline (NMP) from Sideroxylon obtusifolium leaves (a Brazilian medicinal species) presents an anti-inflammatory action. Considering inflammation as an important event in the wound healing process, the objectives were to investigate the topical effects of the NMP gel on a mice wound-induced model. Male Swiss mice were divided into 4 groups: Sham (surgical procedure only), Control (gel-base treated), and 3% or 10% NMP gel-treated groups. Measurements of wound areas and microscopic analyses (HE [hematoxylin-eosin] and PSR [picrosirius red] stainings) were carried out, at the 7th and 12th, days after the wound induction. Furthermore, immunohistochemical assays for iNOS (inducible nitric oxide synthase) and COX-2 (cyclooxygenase-2) and biochemical measurements for TBARS (thiobarbituric acid reactive substances), GSH (glutathione), and myeloperoxidase (MPO) were also performed, at the second day after the wound induction. The work showed that NMP decreases the wound areas, after topical application, relatively to the Sham and Control groups. In addition, microscopic alterations were reduced and collagen deposition was increased, at the 7th and 12th days, in the 10% NMP group. While iNOS and COX-2 immunostainings and GSH contents increased, in relation to the Sham and Control groups, TBARS and MPO decreased. Altogether, the results showed NMP to improve the wound healing process, by upregulating iNOS and COX-2 activities, reducing lipid peroxidation and MPO activity, and increasing GSH contents. In addition, NMP certainly contributes to the increased collagen deposition. These data may stimulate translational studies dealing with the possible use of NMP from Sideroxylon obtusifolium or from other sources for the management of wound healing.

Determination of amino acid levels in the rat striatum, after administration of ethanol alone and associated with ketamine, a glutamatergic antagonist.

The main goal of this study was to determine the amino acids (glutamate, aspartate, glutamine and tyrosine) levels in the rat striatum, after ethanol administration alone and/or associated with ketamine. In protocol 1 (Et+ketamine-1), ethanol was administered to male Wistar rats until the 7th day, and at the next day the group received only ketamine (25mg/kg, i.p.) up to the 14th day. In protocol 2 (Et+ketamine-2), ethanol was also administered up to the 7th day, and was associated with ketamine from the 8th up to the 14th day. In other groups, animals were treated daily with ethanol (4 g/kg, p.o.), for 7 or 14 days or ketamine daily for 7 days. Controls were administered with distilled water for 7 days. Results showed that, in protocol 1, aspartate (ASP) levels increased after ketamine administration, as compared to the controls. This effect was inhibited in the group Et+ketamine-1. Ethanol (7 days) increased glutamate (GLU) levels, as compared to control, and this effect did not differ significantly from that observed in the ketamine group. When ketamine was administered after the ethanol withdrawal (protocol 1), no alterations in those amino acid concentrations were seen, as compared to the control and ketamine groups. A tendency for increasing GLU levels was observed, after administration of ethanol (14 days) or ketamine alone or associated (protocol 2), when compared to control values. In protocol 2, TYR levels decreased as related to controls and to the 14-day ethanol-treated group. We can assume that ketamine presents only an antagonist effect, in animals pretreated with ethanol, followed by ketamine administered from the 8th day on. This is due to the fact that NMDA receptors are already sensitized, leading to a decrease in these receptors functions and consequently to ASP and GLU releases.

The monoaminergic pathways and inhibition of monoamine transporters interfere with the antidepressive-like behavior of ketamine.

Ketamine (KET), a NMDA receptor antagonist, has been studied for its rapid and efficacious antidepressant effect, even for the treatment-resistant depression. Although depression is a major cause of disability worldwide, the treatment can be feasible, affordable and cost-effective, decreasing the population health burden. We evaluated the antidepressive-like effects of KET and its actions on monoamine contents (DA and its metabolites, as well as 5-HT) and on tyrosine hydroxylase (TH). In addition DAT and SERT (DA and 5-HT transporters, respectively) were also assessed. Male Swiss mice were divided into Control and KET-treated groups. The animals were acutely treated with KET (2, 5 or 10 mg/kg, i.p.) and subjected to the forced swimming test, for evaluation of the antidepressive-like behavior. Imipramine and fluoxetine were used as references. The results showed that KET decreased dose-dependently the immobility time and shortly after the test, the animals were euthanized for striatal dissections and monoamine determinations. In addition, the brain (striata, hippocampi and prefrontal cortices) was immunohistochemically processed for TH, DAT and SERT. KET at its higher dose increased DA and its metabolites (DOPAC and HVA) and mainly 5-HT contents, in mice striata, effects associated with increases in TH and decreases in DAT immunoreactivities. Furthermore, reductions in SERT immunoreactivities were observed in the striatum and hippocampus. The results indicate that KET antidepressive-like effect probably involves, among other factors, monoaminergic pathways, as suggested by the increased striatal TH immunoreactivity and reduced brain DA (DAT) and 5-HT (SERT) transporters.

Doxycycline induces bone repair and changes in Wnt signalling.

Doxycycline (DOX) exhibits anti-inflammatory and MMP inhibitory properties. The objectives of this study were to evaluate the effects of DOX on alveolar bone repair. Controls (CTL) and DOX-treated (10 and 25 mg·kg-1) molars were extracted, and rats were killed 7 or 14 days later. The maxillae were processed and subjected to histological and immunohistochemical assays. Hematoxylin-eosin staining (7th day) revealed inflammation in the CTL group that was partly reversed after DOX treatment. On the 14th day, the CTL group exhibited bone neoformation, conjunctive tissue, re-epithelization and the absence of inflammatory infiltrate. DOX-treated groups exhibited complete re-epithelization, tissue remodelling and almost no inflammation. Picrosirius red staining in the DOX10 group (7th and 14th days) revealed an increased percentage of type I and III collagen fibres compared with the CTL and DOX25 groups. The DOX10 and DOX25 groups exhibited increases in osteoblasts on the 7th and 14th days. However, there were fewer osteoclasts in the DOX10 and DOX25 groups on the 7th and 14th days. Wnt-10b-immunopositive cells increased by 130% and 150% on the 7th and 14th days, respectively, in DOX-treated groups compared with the CTL group. On the 7th day, Dickkopf (Dkk)-1 immunostaining was decreased by 63% and 46% in the DOX10 and DOX25 groups, respectively. On the 14th day, 69% and 42% decreases in immunopositive cells were observed in the DOX10 and DOX25 groups, respectively, compared with the CTL group. By increasing osteoblasts, decreasing osteoclasts, activating Wnt 10b and neutralising Dkk, DOX is a potential candidate for bone repair in periodontal diseases.

The anti-inflammatory effects of N-methyl-(2S,4R)-trans-4-hydroxy-l-proline from Syderoxylon obtusifolium are related to its inhibition of TNF-alpha and inflammatory enzymes.

BACKGROUND: Sideroxylon obtusifolium (Roem. & Schult.) T.D. Penn., Sapotaceae family, is a medicinal species native to the Brazilian Northeastern region. The plant is popularly used as an anti-inflammatory and hypoglycemic. PURPOSE: To evaluate the anti-inflammatory properties of the N-methyl-(2S,4R)-trans-4-hydroxy-l-proline (NMP) from S. obtusifolium leaves in models of inflammation and to clarify its action mechanisms. METHODS: Male Swiss mice were distributed intocontrols and groups treated with NMP (25, 50 and 100mg/kg, p.o.), indomethacin or morphine (reference drugs). The animals were subjected to the formalin, carrageenan-induced edema and peritonitis tests. Furthermore, peritoneal lavage and slices from edematous paws were used for histological and immunohistochemical (iNOS, TNF-alpha, COX-2 and NF-kB) assays. RESULTS: Decreases in licking time, in the 1st and mainly in the 2nd phases of the formalin test, were shown after NMP treatments. In addition, decreases (around 50%) in paw edema were noticed at the 3rd h. The HE staining of paw slices demonstrated a complete reversion of the increased PMN cell numberafter NMP treatment. Similarly, decreases higher than 70% were also demonstrated in PMN cells, in the peritoneal fluid. Furthermore, NMP significantly decreased iNOS, TNF-alpha, COX-2 and NF-kB immunoreactivities. CONCLUSIONS: We showed that S. obtusifolium presents a potent anti-inflammatory activity, due to the presence of the N-methyl-(2S,4R)-trans-4-hydroxy-l-proline(NMP) in the plant extract. This action is related to the inhibition by NMP of TNF-alpha and inflammatory enzymes.

Curcumin reverses neurochemical, histological and immuno-histochemical alterations in the model of global brain ischemia.

Curcumin, a curcuminoid from Curcuma longa, presents antioxidant and anti-inflammatory actions and, among pathological changes of cerebral ischemic injury, inflammation is an important one. The objectives were to study the neuroprotective action of curcumin, in a model of global ischemia. Male Wistar rats (sham-operated, ischemic untreated and ischemic treated with curcumin, 25 or 50 mg/kg, p.o.) were anesthesized and their carotid arteries occluded, for 30 min. The SO group had the same procedure, except for carotid occlusion. In the 1st protocol, animals were treated 1 h before ischemia and 24 h later; and in the 2nd protocol, treatments began 1 h before ischemia, continuing for 7 days. Twenty four hours after the last administration, animals were euthanized and measurements for striatal monoamines were performed, at the 1st and 7th days after ischemia, as well as histological and immunohistochemical assays in hippocampi. We showed in both protocols, depletions of DA and its metabolites (DOPAC and HVA), in the ischemic group, but these effects were reversed by curcumin. Additionally, a decrease seen in 5-HT contents, 1 day after ischemia, was also reversed by curcumin. This reversion was not seen 7 days later. On the other hand, a decrease observed in NE levels, at the 7th day, was totally reversed by curcumin. Furthermore, curcumin treatments increased neuronal viability and attenuated the immunoreactivity for COX-2 and TNF-alpha, in the hippocampus in both protocols. We showed that curcumin exerts neuroprotective actions, in a model of brain ischemia that are probably related to its anti-inflammatory activity.

Omega-3 Fatty Acids: Possible Neuroprotective Mechanisms in the Model of Global Ischemia in Rats.

Background. Omega-3 (ω3) administration was shown to protect against hypoxic-ischemic injury. The objectives were to study the neuroprotective effects of ω3, in a model of global ischemia. Methods. Male Wistar rats were subjected to carotid occlusion (30 min), followed by reperfusion. The groups were SO, untreated ischemic and ischemic treated rats with ω3 (5 and 10 mg/kg, 7 days). The SO and untreated ischemic animals were orally treated with 1% cremophor and, 1 h after the last administration, they were behaviorally tested and euthanized for neurochemical (DA, DOPAC, and NE determinations), histological (Fluoro jade staining), and immunohistochemical (TNF-alpha, COX-2 and iNOS) evaluations. The data were analyzed by ANOVA and Newman-Keuls as the post hoc test. Results. Ischemia increased the locomotor activity and rearing behavior that were partly reversed by ω3. Ischemia decreased striatal DA and DOPAC contents and increased NE contents, effects reversed by ω3. This drug protected hippocampal neuron degeneration, as observed by Fluoro-Jade staining, and the increased immunostainings for TNF-alpha, COX-2, and iNOS were partly or totally blocked by ω3. Conclusion. This study showed a neuroprotective effect of ω3, in great part due to its anti-inflammatory properties, stimulating translational studies focusing on its use in clinic for stroke managing.

Pentoxifylline Neuroprotective Effects Are Possibly Related to Its Anti-Inflammatory and TNF-Alpha Inhibitory Properties, in the 6-OHDA Model of Parkinson's Disease.

Pentoxifylline (PTX) is a phosphodiesterase inhibitor with anti-TNF-alpha activity, associated with its anti-inflammatory action. Considering Parkinson's disease (PD) as a neuroinflammatory disorder, the objectives were to evaluate PTX neuroprotective properties, in a model of PD. Male Wistar rats, divided into sham-operated (SO), untreated 6-OHDA, and 6-OHDA treated with PTX (10, 25, and 50 mg/kg) groups, received a unilateral 6-OHDA injection, except the SO group administered with saline. Treatments started 24 h after surgery and continued for 15 days when the animals were submitted to apomorphine-induced rotations, open field, and forced swimming tests. At the next day, they were euthanized and their striata processed for neurochemical (DA and DOPAC determinations), histological, and immunohistochemical (Fluoro-Jade, TH, DAT, OX-42, TNF-alpha, COX-2, and iNOS) studies. PTX reversed the behavioral changes observed in the untreated 6-OHDA animals. Furthermore, PTX partially reversed the decrease in DA contents and improved neuronal viability. In addition, decreases in immunostaining for TH and dopamine transporter (DAT) were reversed. The untreated 6-OHDA group showed intense OX-42, TNF-alpha, COX-2, and iNOS immunoreactivities, which were attenuated by PTX. In conclusion, we demonstrated a neuroprotective effect of PTX, possibly related to its anti-inflammatory and antioxidant actions, indicating its potential as an adjunct treatment for PD.

Pentoxifylline reduces the inflammatory process in diabetic rats: relationship with decreases of pro-inflammatory cytokines and inducible nitric oxide synthase.

Studies suggest that inflammation is a key factor in the pathogenesis of diabetes mellitus. Pro-inflammatory cytokines, such as IL-6 and TNF-alpha, are produced by adipose tissue in large quantities, in obese and especially in diabetic individuals. Pentoxifylline (PTX) is a non-selective phosphodiesterase inhibitor with anti-inflammatory and antioxidant actions that may contribute to alleviate diabetes side effects, as neuropathy, retinopathy and nephropathy. This study aims to investigate PTX anti-inflammatory effects on the carrageenan-induced paw edema model, in alloxan-induced diabetic rats. Diabetic animals (male Wistar rats, 200-250 g) were daily treated with PTX (25, 50, 100 mg/kg, p.o.), glibenclamide (GLI, 5 mg/kg, p.o., as reference) or water, for 5 days. Afterwards, carrageenan-treated paws were dissected, their skin removed and the tissue used for preparation of homogenates and measurements of IL-6 and TNF-alpha by Elisa. Serum levels of nitrite were also determined and paw slices used for iNOS immunohistochemistry assays. We showed that diabetic rats presented an amplification of the inflammatory response, as related to non-diabetic rats, what was evident 48 h after the edema-induction. The PTX-treatment of diabetic rats reduced glycemia (as related to untreated-diabetic ones) and the paw edema. It also brought edema volumes to values similar to those of non-diabetic rats, at the same observation time. The increased TNF-alpha and IL-6 levels in paws of untreated-diabetic rats were reduced in diabetic animals after PTX treatments. Besides, the increased levels of nitrite in the serum of diabetic rats were also decreased by PTX. Furthermore, a higher number of iNOS immunostained cells was demonstrated in paw tissues from untreated-diabetic rats, as related to those of PTX-treated diabetic animals. Our results show that PTX reduces inflammatory parameters, as pro-inflammatory cytokines and iNOS expression, indicating the potential benefit of the drug for the treatment of diabetes and related pathologic conditions.

Valproic Acid Neuroprotection in the 6-OHDA Model of Parkinson's Disease Is Possibly Related to Its Anti-Inflammatory and HDAC Inhibitory Properties.

Parkinson's disease is a neurodegenerative disorder where the main hallmark is the dopaminergic neuronal loss. Besides motor symptoms, PD also causes cognitive decline. Although current therapies focus on the restoration of dopamine levels in the striatum, prevention or disease-modifying therapies are urgently needed. Valproic acid (VA) is a wide spectrum antiepileptic drug, exerting many biochemical and physiological effects. It has been shown to inhibit histone deacetylase which seems to be associated with the drug neuroprotective action. The objectives were to study the neuroprotective properties of VA in a model of Parkinson's disease, consisting in the unilateral striatal injection of the neurotoxin 6-OHDA. For that, male Wistar rats (250 g) were divided into the groups: sham-operated (SO), untreated 6-OHDA-lesioned, and 6-OHDA-lesioned treated with VA (25 or 50 mg/kg). Oral treatments started 24 h after the stereotaxic surgery and continued daily for 2 weeks, when the animals were subjected to behavioral evaluations (apomorphine-induced rotations and open-field tests). Then, they were sacrificed and had their mesencephalon, striatum, and hippocampus dissected for neurochemical (DA and DOPAC determinations), histological (Fluoro-Jade staining), and immunohistochemistry evaluations (TH, OX-42, GFAP, TNF-alpha, and HDAC). The results showed that VA partly reversed behavioral and neurochemical alterations observed in the untreated 6-OHDA-lesioned rats. Besides, VA also decreased neuron degeneration in the striatum and reversed the TH depletion observed in the mesencephalon of the untreated 6-OHDA groups. This neurotoxin increased the OX-42 and GFAP immunoreactivities in the mesencephalon, indicating increased microglia and astrocyte reactivities, respectively, which were reversed by VA. In addition, the immunostainings for TNF-alpha and HDAC demonstrated in the untreated 6-OHDA-lesioned rats were also decreased after VA treatments. These results were observed not only in the CA1 and CA3 subfields of the hippocampus, but also in the temporal cortex. In conclusion, we showed that VA partly reversed the behavioral, neurochemical, histological, and immunohistochemical alterations observed in the untreated 6-OHDA-lesioned animals. These effects are probably related to the drug anti-inflammatory activity and strongly suggest that VA is a potential candidate to be included in translational studies for the treatment of neurodegenerative diseases as PD.

Antinociceptive Effect of the Essential Oil Obtained from the Leaves of Croton cordiifolius Baill. (Euphorbiaceae) in Mice.

Croton cordiifolius Baill. is a shrub known as "quebra-faca" and is used to treat inflammation, pain, wounds, and gastrointestinal disturbances in the semiarid region in the northeast of Brazil. In an ethnobotanical survey in the state of Pernambuco, "quebra-faca" use was cited in 33% of the interviews. Thus, we decided to evaluate the antinociceptive effects of the essential oil from C. cordiifolius (CcEO). Chemical analysis by gas chromatography-mass spectrometry revealed 1,8-cineole (25.09%) and α-phellandrene (15.43%) as major constituents. Antinociceptive activity was evaluated using murine models of chemically induced pain (writhing induced by acetic acid, formalin, capsaicin, and glutamate tests). Opioid and central nervous systems (CNS) involvement were also investigated. Regarding antinociceptive activity, CcEO (50 and 100 mg/kg) reduced the number of writhing responses induced by acetic acid and decreased the licking times in both phases of the formalin test. CcEO also was evaluated in capsaicin- and glutamate-induced nociception. While no effect was observed in the capsaicin test, CcEO (100 mg/kg) was effective in the glutamate test. Naloxone, an opioid antagonist, did not affect the antinociceptive activity of CcEO in writhing test. In conclusion, the antinociceptive effect of CcEO could be explained, at least in part, by inhibition of the glutamatergic system.

[Buspirone increases D2-like dopaminergic receptor density in rat corpus striatum]. / Buspirona aumenta a densidade de receptores dopaminérgicos D2- símile em corpo estriado de rato.

Buspirone (busp) a piperazinyl derivative with anxiolytic properties is a partial agonist on 5-HT1A with affinity for D2-like dopaminergic receptors (RD2). The objective of this study was to verify the effects of busp on RD2. Female Wistar rats 150-200 g were treated with busp (5 and 10 mg/kg, p.o.) 1 or 2 times daily for 7 days. Controls (C) received saline. The density of RD2 (fmol/mg protein) was determined through binding assays in striatum (ST) using [3H]-spiroperidol as radioligand. No alteration in Bmax or Kd values were seen after busp administration once a day. However, a RD2 upregulation of 55 % increase was observed after busp 2 times a day with no change in Kd values. The results showed that busp interact not only with serotonergic, but also with dopaminergic system.