Environmental training is beneficial to clinical symptoms and cortical presynaptic defects in mice suffering from experimental autoimmune encephalomyelitis.

The effect of "prophylactic" environmental stimulation on clinical symptoms and presynaptic defects in mice suffering from the experimental autoimmune encephalomyelitis (EAE) at the acute stage of disease (21 ±â€¯1 days post immunization, d.p.i.) was investigated. In EAE mice raised in an enriched environment (EE), the clinical score was reduced when compared to EAE mice raised in standard environment (SE).Concomitantly, gain of weight and increased spontaneous motor activity and curiosity were observed, suggesting increased well-being in mice. Impaired glutamate exocytosis and cyclic adenosine monophosphate (cAMP) production in cortical terminals of SE-EAE mice were evident at 21 ±â€¯1 d.p.i.. Differently, the 12 mM KCl-evoked glutamate exocytosis from cortical synaptosomes of EE-EAE mice was comparable to that observed in SE and EE-control mice, but significantly higher than that in SE-EAE mice. Similarly, the 12 mM KCl-evoked cAMP production in EE-EAE mice cortical synaptosomes recovered to the level observed in SE and EE-control mice. MUNC-18 and SNAP25 contents, but not Syntaxin-1a and Synaptotagmin 1 levels, were increased in cortical synaptosomes from EE-EAE mice when compared to SE-EAE mice. Circulating IL-1ß was increased in the spinal cord, but not in the cortex, of SE-EAE mice, and it did not recover in EE-EAE mice. Inflammatory infiltrates were reduced in the cortex but not in the spinal cord of EE-EAE mice. Demyelination was observed in the spinal cord; EE significantly diminished it. We conclude that "prophylactic" EE is beneficial to synaptic derangements and preserves glutamate transmission in the cortex of EAE mice. This article is part of the Special Issue entitled "Neurobiology of Environmental Enrichment".

Fumarate-loaded electrospun nanofibers with anti-inflammatory activity for fast recovery of mild skin burns.

In the biomedical sector the availability of engineered scaffolds and dressings that control and reduce inflammatory states is highly desired, particularly for the management of burn wounds. In this work, we demonstrate for the first time, to the best of our knowledge, that electrospun fibrous dressings of poly(octyl cyanoacrylate) (POCA) combined with polypropylene fumarate (PPF) possess anti-inflammatory activity and promote the fast and effective healing of mild skin burns in an animal model. The fibers produced had an average diameter of (0.8 ± 0.1) µm and they were able to provide a conformal coverage of the injured tissue. The application of the fibrous mats on the burned tissue effectively reduced around 80% of the levels of pro-inflammatory cytokines in the first 48 h in comparison with un-treated animals, and enhanced skin epithelialization. From histological analysis, the skin thickness of the animals treated with POCA : PPF dressings appeared similar to that of one of the naïve animals: (13.7 ± 1.4) µm and (14.3 ± 2.5) µm for naïve and treated animals, respectively. The density of dermal cells was comparable as well: (1100 ± 112) cells mm(-2) and (1358 ± 255) cells mm(-2) for naïve and treated mice, respectively. The results demonstrate the suitability of the electrospun dressings in accelerating and effectively promoting the burn healing process.

Pharmacological characterization of the peripheral FAAH inhibitor URB937 in female rodents: interaction with the Abcg2 transporter in the blood-placenta barrier.

BACKGROUND AND PURPOSE: URB937 is a peripherally restricted inhibitor of the anandamide-deactivating enzyme fatty-acid amide hydrolase (FAAH). Despite its limited access to the CNS, URB937 produces marked antinociceptive effects in rodents. URB937 is actively extruded from the CNS by the ATP-binding cassette (ABC) membrane transporter, Abcg2. Tissue Abcg2 levels are markedly different between males and females, and this transporter is known to limit the access of xenobiotics to the fetoplacental unit in gestating female rodents. In the present study, we investigated the tissue distribution and antinociceptive properties of URB937 in female mice and rats. EXPERIMENTAL APPROACH: We studied the systemic disposition of URB937 in female mice and the antinociceptive effects of this compound in models of visceral (acetic acid-induced writhing) and inflammatory nociception (carrageenan-induced hyperalgesia) in female mice and rats. Furthermore, we evaluated the interaction of URB937 with the blood-placenta barrier in gestating mice and rats. KEY RESULTS: Abcg2 restricted the access of URB937 to the CNS of female mice and rats. Nevertheless, URB937 produced a high degree of antinociception in female mice and rats in models of visceral and inflammatory pain. Moreover, the compound displayed a restricted access to placental and fetal tissues in pregnant mice and rats. CONCLUSIONS AND IMPLICATIONS: Peripheral FAAH blockade with URB937 reduces nociception in female mice and rats, as previously shown for males of the same species. In female mice and rats, Abcg2 limits the access of URB937, not only to the CNS, but also to the fetoplacental unit. LINKED ARTICLES This article is part of a themed section on Cannabinoids. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.167.issue-8.

Quantitation of fetal DNA in maternal serum during the first trimester of pregnancy by the use of a DAZ repetitive probe.

Cell-free fetal DNA in maternal plasma or serum is at present widely investigated as a source of fetal genetic material, both in studies of pregnancy-related disorders and in planning strategies for non-invasive prenatal diagnosis. Despite the number of trials already performed on the quantitation of fetal DNA, data about the amount of DNA at the beginning of pregnancy, in particular in the first trimester, remain limited. A new probe mapping on the deleted in azoospermia (DAZ) repetitive region of the Yq chromosome was designed for an early assessment of fetal DNA concentration in maternal serum. Among 57 pregnant women prospectively studied in their first trimester, fetal DNA was detected already by the 5th gestational week, with the analysis becoming reliable by the 8th week of gestation when a 100% accuracy in fetal sex determination was achieved. Moreover, in the three cases of pregnancy ending in fetal loss, the amount of fetal DNA apparently decreased before the abortion was diagnosed, whereas it consistently showed an increasing trend in normal pregnancies. Real-time PCR with the use of DAZ multilocus probe can efficiently quantitate free fetal DNA in the maternal serum at the beginning of pregnancy.

CB2 receptor-mediated antihyperalgesia: possible direct involvement of neural mechanisms.

In mouse the cannabinoid receptor 2 (CB2) agonists L768242 and (+)-AM1241, at doses of 30 mg/kg i.p. and 1 and 3 mg/kg i.v., respectively, reduced the second phase of nocifensive behaviors elicited by formalin intraplantar injection. This effect was counteracted by the selective CB2 antagonist SR144528 (1 mg/kg i.p.). In rat (+)-AM1241 (3 and 6 mg/kg i.v.) and L768242 (30 mg/kg i.p.) reduced allodynia elicited by L5-L6 spinal nerve ligation. SR144528 reverted these effects, supporting a CB2-mediated action. To clarify the mechanisms underlying these effects we investigated CB2 gene expression and function in the nervous system. CB2 mRNA was expressed in spinal cord and dorsal root ganglia (DRG) of both sham and neuropathic rats and was up-regulated in the ipsilateral spinal cord of neuropathic rats. Expression studies demonstrated the presence of CB2 mRNA in culture of spinal cord microglia. A biomarker, CGRP, was used to investigate modulation of DRG primary afferents by CB2 agonists. Both L768242 and (+)-AM1241 dose dependently (EC50 of 3.6 and 4.5 nM, respectively) reduced capsaicin-induced calcitonin gene-related peptide (CGRP) release. Coadministration of SR144528 resulted in a rightforward shift (pKB 8.1 and 8.2 for (+)-AM1241 and L768242, respectively) of the dose-response curve. Experiments on capsaicin-induced CGRP release in tissue from CB1-/- mice ruled out a CB1-mediated effect. These results confirm that CB2 is present in the central nervous system and suggest that CB2 agonists may elicit their analgesic effect by acting not only at non-neuronal peripheral sites but also at neural level, making CB2 an attractive target for chronic pain treatment.

Blockade of nociceptin/orphanin FQ-NOP receptor signalling produces antidepressant-like effects: pharmacological and genetic evidences from the mouse forced swimming test.

Nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the NOP receptor, regulates several central functions such as pain transmission, learning and memory, fear and anxiety and feeding and locomotor activity. It has been recently reported that NOP receptor antagonists induce antidepressant-like effects in the mouse forced swimming test (FST), i.e. reduce immobility time. This assay was used in the present study for further investigating the involvement of the NOP receptor in depression states. In male Swiss mice, intracerebroventricular injection (i.c.v) of the novel NOP receptor antagonist, UFP-101 (1-10 nmol) dose-dependently reduced the immobility time (control 192 +/- 14 s, UFP-101 91 +/- 15 s). The effect of 3 or 10 nmol UFP-101 was fully or partially reversed, respectively, by the coadministration of 1 nmol N/OFQ, which was inactive per se. NOP receptor knockout mice showed a reduced immobility time compared with their wild-type littermates (wild-type 215 +/- 10 s, knockout 143 +/- 12 s). Moreover, i.c.v. injected UFP-101 (10 nmol) significantly reduced immobility time in wild-type mice but not in NOP receptor knockout animals. In conclusion, these results, obtained using a combined pharmacological and genetic approach, indicate that blockade of the N/OFQ-NOP receptor signalling in the brain produces antidepressant-like effects in the mouse FST. These findings support the NOP receptor as a candidate target for the development of innovative antidepressant drugs.

Studies on the antinociceptive effect of [Nphe1]nociceptin(1-13)NH2 in mice.

Nociceptin/orphanin FQ (NC) and its receptor (OP(4)) have been implicated in the regulation of various functions including nociception. [Nphe(1)]NC(1-13)NH(2) (Nphe) is a selective OP(4) antagonist which prevents the pronociceptive effects of supraspinal NC and causes per se a naloxone-insensitive antinociceptive effect. In the present study, we tested Nphe in wild type (WT) and OP(4) receptor knock out mice and found that a clear antinociceptive effect of the antagonist was evident only in WT mice. Moreover, we evaluated, over 5 days of treatment, the antinociceptive effects of Nphe in comparison with those of DAMGO and found that tolerance develops to the effects of the opioid receptor agonist but not to Nphe. These data demonstrate that the antinociceptive action of Nphe is due to the block of OP(4) receptors and that no tolerance develops to this kind of antinociception.

Reverse-transcriptase polymerase chain reaction of the maspin gene in the detection of bone marrow breast carcinoma cell contamination.

BACKGROUND: Maspin is a molecular marker used for the detection of contaminating breast carcinoma (BC) cells in peripheral blood and lymph nodes. However, its specificity has been questioned recently. The objective of this study was to verify the specificity of this marker and to determine the incidence of positive bone marrow results in patients with BC who are eligible for high-dose chemotherapy (HDT) both in early and advanced disease stages and before and after treatment. METHODS: Bone marrow specimens from 41 patients with BC as well as from 35 normal volunteers and 17 patients with hematologic tumors were examined for maspin transcript expression by a modified nested reverse transcriptase-polymerase chain reaction technique. RESULTS: Maspin transcript was found in all normal and neoplastic breast tissues and in none of the 35 normal bone marrow specimens (specificity, 100%; 95% confidence interval, 90-100%). However, the transcript was found in 40% of the bone marrow samples from patients with hematologic malignancies. Thus, this marker appears very specific for discriminating between normal controls and patients with BC, but it cannot be considered disease specific. Among patients with BC, bone marrow was positive for the maspin transcript in 32% of patients with early-stage disease and in 75% of patients with metastatic disease before chemotherapy. After treatment, in 75% of patients with early-stage disease and in 50% of patients with metastatic disease, the bone marrow results became maspin negative. CONCLUSIONS: On the basis of the current data, although it is not disease specific, maspin is a reliable marker for detecting bone marrow molecular disease in patients with BC and should be considered for prospective studies as a prognostic indicator and as an assay for monitoring residual disease.

Adenosine A2A receptor antagonists are potential antidepressants: evidence based on pharmacology and A2A receptor knockout mice.

1. Adenosine, an ubiquitous neuromodulator, and its analogues have been shown to produce 'depressant' effects in animal models believed to be relevant to depressive disorders, while adenosine receptor antagonists have been found to reverse adenosine-mediated 'depressant' effect. 2. We have designed studies to assess whether adenosine A2A receptor antagonists, or genetic inactivation of the receptor would be effective in established screening procedures, such as tail suspension and forced swim tests, which are predictive of clinical antidepressant activity. 3. Adenosine A2A receptor knockout mice were found to be less sensitive to 'depressant' challenges than their wildtype littermates. Consistently, the adenosine A2A receptor blockers SCH 58261 (1 - 10 mg kg(-1), i.p.) and KW 6002 (0.1 - 10 mg kg(-1), p.o.) reduced the total immobility time in the tail suspension test. 4. The efficacy of adenosine A2A receptor antagonists in reducing immobility time in the tail suspension test was confirmed and extended in two groups of mice. Specifically, SCH 58261 (1 - 10 mg kg(-1)) and ZM 241385 (15 - 60 mg kg(-1)) were effective in mice previously screened for having high immobility time, while SCH 58261 at 10 mg kg(-1) reduced immobility of mice that were selectively bred for their spontaneous 'helplessness' in this assay. 5. Additional experiments were carried out using the forced swim test. SCH 58261 at 10 mg kg(-1) reduced the immobility time by 61%, while KW 6002 decreased the total immobility time at the doses of 1 and 10 mg kg(-1) by 75 and 79%, respectively. 6. Administration of the dopamine D2 receptor antagonist haloperidol (50 - 200 microg kg(-1) i.p.) prevented the antidepressant-like effects elicited by SCH 58261 (10 mg kg(-1) i.p.) in forced swim test whereas it left unaltered its stimulant motor effects. 7. In conclusion, these data support the hypothesis that A2A receptor antagonists prolong escape-directed behaviour in two screening tests for antidepressants. Altogether the results support the hypothesis that blockade of the adenosine A2A receptor might be an interesting target for the development of effective antidepressant agents.

The putative OP(4) antagonist, [Nphe(1)]nociceptin(1-13)NH(2), prevents the effects of nociceptin in neuropathic rats.

Nociceptin or orphanin FQ (N/OFQ) is the natural ligand of the opioid receptor-like 1 receptor (ORL-1), which has been also classified as the fourth member of the opioid family of receptors and named OP(4). Elucidation of the biological role of N/OFQ has been hampered by the lack of compounds that selectively block the OP(4) receptor. Recently, a N/OFQ derivative, [Nphe(1)]N/OFQ(1-13)NH(2), has been found to possess OP(4) antagonistic properties both in vitro and in vivo models. We investigated its spinal effect in the chronic constriction injury of the sciatic nerve in the rat, a model relevant to neuropathic pain in humans. Intrathecal (i.t.) administration of N/OFQ (0.2--20 nmoles) dose-dependently reversed mechanical allodynic-like behavior, while [Nphe(1)]N/OFQ(1-13)NH(2) (20--120 nmoles, i.t.) was ineffective on its own. [Nphe(1)]N/OFQ(1-13)NH(2) (60--120 nmoles, i.t.) antagonized N/OFQ (about 80% of reduction) but did not modify the activity of morphine (20 nmoles, i.t.). These results further support, for the first time in a chronic model of pain, the specific antagonistic profile of [Nphe(1)]N/OFQ(1-13)NH(2)vs the OP(4) receptor. This pseudopeptide is an interesting pharmacological tool to better clarify the role of N/OFQ in pathophysiology.

Nociceptin attenuates opioid and gamma-aminobutyric acid(B) receptor-mediated analgesia in the mouse tail-flick assay.

Nociceptin (NC) and the opioid receptor like-1 receptors are widely distributed in areas of the neuraxis that are part of the descending modulatory pain system. We used the tail-flick assay in mice to assess the interaction between NC and other analgesic compounds acting on different areas of the descending pathway. Given by intracerebroventricular injection, NC induced hyperalgesia at 10 nmol (39% of reduction vs. control group). The same dose of NC reversed analgesia induced by distinct classes of analgesia-producing compounds such as morphine, dynorphin A or baclofen. NC caused a reduction of their antinociceptive effects: 61, 41 and 27%, respectively. Thus, NC at the supraspinal level appears to interact with both opioid and gamma-aminobutyric acid(B) systems producing anti-analgesic effects probably through the descending pathway for pain control.

Nociceptin and the ORL-1 ligand [Phe1psi (CH2-NH)Gly2]nociceptin(1-13)NH2 exert anti-opioid effects in the Freund's adjuvant-induced arthritic rat model of chronic pain.

1 Stimulation of the opioid receptor-like1 (ORL-1) receptor by nociceptin (NC) produces hyperalgesia and reverses the antinociceptive effects induced by opioids. Most studies concerning the central effects of NC were conducted using acute pain models. The role NC may play in chronic inflammation remains unelucidated. 2 The present study was undertaken to assess the action of NC in the Freund's adjuvant-induced monoarthritic rat model. The effects of drugs known to act as analgesics in this model were evaluated. The effects of NC, NCNH2, and the ORL-1 ligand, [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 ([F/G]NC(1-13)NH2), were also studied alone or in association with morphine. 3 NC (1 - 30 nmol, i. c.v.) was inactive, whilst NCNH2 (10 nmol, i.c.v.) exerted hyperalgesic effects (-4.5+/-0.9 vs -0.7+/-0.8 s of vehicle-treated animals). [F/G]NC(1-13)NH2 (0.01 - 10 nmol, i.c.v.) induced hyperalgesia in the arthritic paw (-3.3+/-0.6 vs -0.3+/-0.5 s of vehicle-treated animals; 10 nmol). 4 Both NC (0.01 - 10 nmol, i.c.v. ) and [F/G]NC(1-13)NH2 (0.01 - 1 nmol, i.c.v), 30 min after morphine (3 mg kg-1, s.c.) induced an immediate and short-lived reversal of morphine effects (2.6+/-0.3 vs 10.4+/-1.0 and 1.2+/-1.5 vs 9.3+/-1.1 s of morphine alone, respectively), therefore displaying anti-opioid activity. 5 In the Freund's adjuvant-induced rat model of arthritis, both NC and [F/G]NC(1-13)NH2 act as anti-opioid peptides. Furthermore, NCNH2 and [F/G]NC(1-13)NH2 induce hyperalgesia when given alone. Further investigations and the identification of a centrally acting ORL-1 antagonist are necessary to better understand the role of NC in pain mechanisms.

Striatal outflow of adenosine, excitatory amino acids, gamma-aminobutyric acid, and taurine in awake freely moving rats after middle cerebral artery occlusion: correlations with neurological deficit and histopathological damage.

BACKGROUND AND PURPOSE: While a number of studies have investigated transmitter outflow in anesthetized animals after middle cerebral artery occlusion (MCAO) performed by craniectomy, studies have never been performed after MCAO induced by intraluminal filament. In addition, it has been reported that after MCAO, infarct volume correlates with functional outcome and with transmitter outflow, although there are no studies that demonstrate a direct correlation between transmitter outflow and functional outcome. The purpose of the present study was to assess excitatory amino acids, gamma-aminobutyric acid, taurine, and adenosine outflow in awake rats after intraluminal MCAO and to determine whether, in the same animal, outflow was correlated with neurological outcome and histological damage. METHODS: Vertical microdialysis probes were placed in the striatum of male Wistar rats. After 24 hours, permanent MCAO was induced by the intraluminal suture technique. The transmitter concentrations in the dialysate were determined by high-performance liquid chromatography. Twenty-four hours after MCAO, neurological deficit and histological outcome were evaluated. RESULTS: All transmitters significantly increased after MCAO. Twenty-four hours after MCAO, the rats showed a severe sensorimotor deficit and massive ischemic damage in the striatum and in the cortex (9+/-2% and 25+/-6% of hemispheric volume, respectively). Significant correlations were found between the efflux of all transmitters, neurological score, and striatal infarct volume. CONCLUSIONS: In this study, for the first time, amino acid and adenosine extracellular concentrations during MCAO by the intraluminal suture technique were determined in awake and freely moving rats, and a significant correlation was found between transmitter outflow and neurological deficit. The evaluation of neurological deficit, histological damage, and transmitter outflow in the same animal may represent a useful approach for studying neuroprotective properties of new drugs/agents against focal ischemia.

Effects of adenosine receptor agonists and antagonists on audiogenic seizure-sensible DBA/2 mice.

We have studied the effects of selective and non-selective adenosine receptor agonists and antagonists in audiogenic-seizure-sensitive DBA/2 mice, an animal model of generalized reflex epilepsy. With the exception of the adenosine A3 receptor agonist, N6-(3-iodobenzyl)-5'-N-methylcarboxamidoadenosine (IB-MECA), all the agonists studied prevented the development of audiogenic seizures in a dose-dependent manner. The ED50 values against the clonic phase of the audiogenic seizures were low, that is: 0.06 mg/kg, i.p., for the adenosine A1 receptor agonist, 2-chloro-N6-cyclopentyladenosine (CCPA), 0.02 and 0.03 mg/kg, i.p., for the adenosine A2A receptor agonists, 2-(4-(2-carboxyethyl)-phenylamino)-5'-N-ethylcarboxamidoadenosine (CGS 21680) and 2-hexynyl-5'-N-ethyl-carboxamidoadenosine (2-HE-NECA), and 0.7 mg/kg, i.p., for the adenosine A1/A3 receptor agonist, N6-2-(4-aminophenyl)ethyladenosine (APNEA). Conversely, the non-selective agonist, N-ethyl-carboxamidoadenosine (NECA), was highly potent, the ED50 being 0.0005 mg/kg, i.p. In the absence of auditory stimulation, the adenosine receptor antagonists increased the incidence of both clonic and tonic seizures in DBA/2 mice. The ED50 values were: for caffeine, 207.5 mg/kg, i.p., for the adenosine A1 receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), 327.8 mg/kg i.p., for the adenosine A2A receptor antagonists, 3,7-dimethyl-1-propylxanthine (DPMX), 86.7 mg/kg i.p., for the (E,18%-Z,82%)7-methyl-8-(3,4-dimethoxystyryl)-1,3-dipropylxanthine (KF 17837), 69.1 mg/kg i.p., and 5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo-(4,3-c)1,2,4-triazolo(1,5 -c)-pyrimidine (SCH 58261), 321.8 mg/kg i.p. The rank order of convulsant potency in our epileptic model, following intracerebroventricular administration, was DPCPX > DMPX > 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC) > KF 17837 > Caffeine > SCH 58261 > 5-amino-9-chloro-2-(2-furyl)-1,2,4-triazolo(1,5-c)quinazoline (CGS 15943). Following a subconvulsant audiogenic stimulus of 83 dB, all adenosine receptor antagonists induced both tonic and clonic seizures. The ED50 values for such proconvulsant effects were: for caffeine 0.04 mg/kg, i.p., for the adenosine A receptor antagonist, DPCPX, 5.84 mg/kg, i.p., for the adenosine A2A receptor antagonists, DMPX, 0.02 mg/kg, i.p., CGS 15943, 0.29 mg/kg i.p., KF 17837, 0.57 mg/kg, i.p., CSC 0.12 mg/kg, i.p. and SCH 58261 0.07 mg/kg, i.p., respectively. These data suggest that stimulation of adenosine A1 and A2A receptors is involved in the suppression of seizures.

MK 801 and dexamethasone reduce both tumor necrosis factor levels and infarct volume after focal cerebral ischemia in the rat brain.

Focal cerebral ischemia in rats produces elevated levels of tumor necrosis factor (TNF)alpha in the ischemic brain region. To better understand the modulation of TNF during brain ischemia processes we carried out studies in a model of permanent middle cerebral artery occlusion (MCAo) in the rat. In non-treated ischemic animals, the maximum expression of TNF was observed at 12 h (246.1+/-33 U/g) in the ischemic cortex and declined reaching near zero levels 24 h after MCAo. Given 10 min after MCAo, MK 801 (3 mg/kg, i.p.), a non-competitive NMDA receptor antagonist, exerted significant neuroprotection as measured by 47% reduction of total volume of infarction (P < 0.01 vs. ischemic-control). At the high dose of 3 mg/kg i.p., dexamethasone (DEX), which is known to reduce brain edema, decreased infarct size by 50% (P < 0.01 vs. ischemic-control). Both MK 801 and DEX reduced TNF production in the ipsilateral cortex of ischemic animals by 61 and 73%, respectively (P < 0.01 vs. ischemic-control). The data indicate that TNF levels increase after brain infarction, whereas they are reduced by neuroprotective agents, such as MK 801 and DEX, which act on different cellular levels.

Adenosine A2A receptors and neuroprotection.

The adenosine A2A receptor subtype is one of the four adenosine receptors that have been identified in the mammalian organism. In addition to being found in blood vessels, platelets and polymorphonuclear leukocytes, the A2A receptors are abundant in the central nervous system, especially in the striatum. The recent development of selective A2A receptor ligands, in particular of receptor antagonists, makes it possible to elucidate the function of A2A receptors in normal and altered conditions. Pharmacological studies have shown that A2A receptor antagonists are potentially effective for treatment of neurodegenerative processes such as Parkinson's disease. Their activity is attributed to the close anatomical and functional links between A2A receptors and dopaminergic pathways in the basal ganglia. More recently, A2A receptor antagonists have proved to be active in models of cerebral ischemia. While the mechanisms underlying the role of A2A receptors in the hypoxia/ ischemia processes remains to be clarified, it is recognized that A2A receptor antagonists counteract the effects of excitatory aminoacids, which are massively released after cerebral ischemia. Another function of A2A receptors is related to protection from seizures, but further studies are needed to elucidate their specific interaction, if any, with neuronal excitability. Altogether, the great advance recently made with the discovery of selective A2A receptor ligands provides increasing information on the function of A2A receptors and opens new perspectives for treatment of neurological disorders.

Systemic interleukin 10 administration inhibits brain tumor necrosis factor production in mice.

Interleukin 10 is an antiinflammatory cytokine and inhibits the production of tumor necrosis factor. We have previously found that intracerebroventricular (i.c.v.) administration of recombinant human interleukin 10 inhibits brain tumor necrosis factor production induced by an i.c.v. injection of lipopolysaccharide in mice. In view of its possible pharmacological use, we have now studied whether interleukin 10 administered peripherally could inhibit brain tumor necrosis factor production. Mice were injected with recombinant human interleukin 10 (20 microg/mouse, i.v.) 10 min-24 h before lipopolysaccharide (2.5 microg, i.c.v.). Tumor necrosis factor was measured, using a bioassay, in brain homogenates 90 min after lipopolysaccharide. Recombinant human interleukin 10 administered i.v. between 10 min and 6 h before lipopolysaccharide markedly inhibited brain tumor necrosis factor production. We also measured the production of tumor necrosis factor by whole blood of these mice, and it was also markedly inhibited by recombinant human interleukin 10 treatment. In conclusion, systemic recombinant human interleukin 10 administration inhibits brain tumor necrosis factor production. suggesting its usefulness in tumor necrosis factor-mediated pathologies of the central nervous system.

Anticonvulsant activity of 5,7DCKA, NBQX, and felbamate against some chemoconvulsants in DBA/2 mice.

The anticonvulsant effects of felbamate (10-300 mg/kg, intraperitoneally, IP), and those of two representative antagonists of the excitatory amino acid receptors, 5-7 dichlorokynurenic acid (5-7DCKA; 0.6-30 nmol/mouse, intracerebroventricularly, ICV), and 2, 3-dihydroxy-6 nitro-7-sulfamoylbenzo (F) quinoxoline (NBQX; 1.1-33.6 mg/kg, IP) were studied in the DBA/2 mice. All drugs protected the animals from sound-induced seizures. The drugs were also effective against seizures induced by stimulation of the excitatory amino acid receptor complex using the agonists N-methyl-D-aspartate (NMDA) or alpha-amino-3-hydroxy-5 methyl-4-isoxazolepropionic acid (AMPA). In separate studies, felbamate protected mice from seizures induced by ICV administration of the activator of dihydropyridine-sensitive calcium channels, methyl-1, 4-dihydro-2, 6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl) pyridine-5-carboxylate (Bay k 8644), with ED50 values of 26 and 46.9 mg/kg for tonus and clonus, respectively. Using Bay k 8644, NBQX (1-40 mg/kg IP) was uneffective, while 5,7DCKA (5-90 nmol/mouse, ICV) protected mice against tonus. Moreover, felbamate prevented seizures induced by blocking voltage-dependent K+ channels using alpha-dendrotoxin, with ED50 values of 22.6 mg/kg for tonus and of 34.8 mg/kg for clonus. Conversely, 5,7DCKA or NBQX did not significantly antagonize seizures induced by alpha-dendrotoxin. The present data indicate that felbamate is an effective anticonvulsant drug in DBA/2 mice with a broader anticonvulsant spectrum than 5,7DCKA and NBQX.