Blockade of TRPA1 with HC-030031 attenuates visceral nociception by a mechanism independent of inflammatory resident cells, nitric oxide and the opioid system.

BACKGROUND: Some studies have shown a somatic nociceptive response due to the activation of transient receptor potential A1 channels (TRPA1), which is modulated by the TRPA1 antagonist HC-030031. However, a few studies report the role of TRPA1 in visceral pain. Therefore, we investigated the participation of TRPA1 in visceral nociception and the involvement of nitric oxide, the opioid system and resident cells in the modulation of these channels. METHODS: Mice were treated with vehicle or HC-030031 (18.75-300 mg/kg) before ifosfamide (400 mg/kg), 0.75% mustard oil (50 µL/colon), acetic acid 0.6% (10 mL/kg), zymosan (1 mg/cavity) or misoprostol (1 µg/cavity) injection. Visceral nociception was assessed through the electronic von Frey test or the writhing response. Ifosfamide-administered mice were euthanized for bladder analysis. The involvement of nitric oxide and the opioid system were investigated in mice injected with ifosfamide and mustard oil, respectively. The participation of resident peritoneal cells in acetic acid-, zymosan- or misoprostol-induced nociception was also evaluated. RESULTS: HC-030031 failed to protect animals against ifosfamide-induced bladder injury (p > 0.05). However, a marked antinociceptive effect against ifosfamide, mustard oil, acetic acid, zymosan and misoprostol was observed (p < 0.05). Neither L-arginine (600 mg/kg) nor naloxone (2 mg/kg) could reverse the antinociceptive effect of HC-030031. The reduction of the peritoneal cell population inhibited the acetic acid and zymosan-related writhes without interfering with the misoprostol effect. CONCLUSIONS: Our findings suggest that the blockade of TRPA1 attenuates visceral nociception by a mechanism independent of the modulation of resident cells, nitric oxide and opioid pathways.

Lippia sidoides and Myracrodruon urundeuva gel prevents alveolar bone resorption in experimental periodontitis in rats.

In Brazilian folk medicine, Lippia sidoides (Ls) and Myracrodruon urundeuva (Mu) have gained popularity and reputation as effective antimicrobial and anti-inflammatory agents. This work aimed to evaluate the effect of topical herbal gel from Ls 0.5% (v/w) and Mu 5% (w/w) in experimental periodontal disease (EPD) in rats. Wistar rats were subjected to ligature placement around the second upper left molars. Animals were treated topically with Ls and/or Mu-based gel, immediately after EPD induction and three times/day for 11 days until the rats were sacrificed (11th day). Saline-based gel was utilized as control for all experiments and doxycycline based gel 10% (w/w) was utilized as reference substance. Animals were weighed daily. Alveolar bone loss was measured as the difference (in millimeters) between the cusp tip and the alveolar bone. The periodontum and the surrounding gingivae were examined at histopathology, as well as the neutrophil influx into the gingivae was assayed using myeloperoxidase activity and cytokine production mainly tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) levels by ELISA method. The local bacterial flora was assessed through culture of the gingival tissue in standard aerobic and anaerobic media. Alveolar bone loss was significantly inhibited by Ls and Mu combined treatment compared to the saline control group. Ls and Mu combined treatment reduced tissue lesion at histopathology, with partial preservation of the periodontum, coupled to decreased myeloperoxidase activity as well as significantly inhibited TNF-alpha and IL-1beta production in gingival tissue compared to the saline control group. Ls and Mu combined treatment also prevented the growth of oral microorganisms and the weight loss. Ls and Mu combined based gel treatment preserved alveolar bone resorption and demonstrated anti-inflammatory and antibacterial activities in experimental periodontitis.

Anti-inflammatory effect of the latex from Calotropis procera in three different experimental models: peritonitis, paw edema and hemorrhagic cystitis.

Latex from Calotropis procera is widely used in folk medicine as a rich source of biologically active compounds capable of promoting diverse benefits such as control of dermal fungal infections, antimicrobial activities and pain relief among other useful properties. The aim of this work was to characterize the anti-inflammatory effect of a non-dialysable protein fraction recovered from the rubber-free latex using three different experimental models when administrated intravenously. In vivo neutrophil migration induced by carrageenin (500 microg) was severely inhibited by doses of latex proteins reaching maximum inhibition (80%) at 100 mg/kg. Paw edema exacerbated by the effect of carrageenin was almost completely suppressed after 4 hours and was controlled within the first hour following latex protein administration. However, the same latex fraction was completely unable to control the paw edema invoked with dextran stimulation (400 microg), suggesting that the inhibitory effect of the latex is likely to be cell-mediated. Iphosphamide-induced vesical edema in mice was also largely prevented by the latex protein fraction. These results indicate that an effect similar to that of mesna, the classical drug used for this purpose, is operative. Our findings suggest that the sample tested seems to act over a wide spectrum as a novel anti-inflammatory agent. The results also suggest that the active molecules are of a proteinaceous nature despite the presence of numerous secondary metabolites naturally occurring in the C. procera latex.

Ternatin, an anti-inflammatory flavonoid, inhibits thioglycolate-elicited rat peritoneal neutrophil accumulation and LPS-activated nitric oxide production in murine macrophages.

Ternatin, an anti-inflammatory flavonoid from Egletes viscosa Less., was examined for its possible influence on thioglycolate-elicited neutrophil influx into the rat peritoneal cavity in vivo and nitric oxide production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages ex vivo. The neutrophil influx induced by thioglycolate was found to be significantly lower in ternatin (25 and 50 mg/kg, s. c.) pre-treated rats with a similar magnitude of inhibition produced by dexamethasone (1 mg/kg, s. c.), a known anti-inflammatory agent. Also, peritoneal macrophages from ternatin (25 mg/kg)-treated mice that were exposed to LPS demonstrated significantly less production of nitric oxide (NO). These results suggest that ternatin exerts its anti-inflammatory action, at least in part, through inhibition of neutrophil migration and modulation of macrophage function.

Nantenine alkaloid presents anticonvulsant effect on two classical animal models.

The present study investigated the anticonvulsant and convulsant profiles of nantenine, an aporphine alkaloid found in several vegetal species. At lower doses (20-50 mg/kg, i.p.) the alkaloid proved to be effective in inhibiting pentylenotetrazol- (PTZ 100 mg/kg, s.c.) and maximal electroshock-induced seizures (80 mA, 50 pulses/s, 0.2 s), suggesting its potential as an anticonvulsant drug. However, at higher doses (> or = 75 mg/kg, i.p.) a convulsant activity was observed. Comparing the present in vivo nantenine effects on seizures with previous in vitro biphasic action on Na+, K+-ATPase activity, the convulsant effect appears to be related to inhibition of these phosphatase at high doses whereas anticonvulsant effect, observed at low doses, seems attributable to its stimulation and the resultant decrease of Ca2+-influx into the cell.

Anti-inflammatory and smooth muscle relaxant activities of the hydroalcoholic extract and chemical constituents from Amburana cearensis A C Smith.

Amburana cearensis A. C. Smith, Fagaceae, is a medicinal plant commonly known as 'cumaru' and used in Northeast Brazil for the treatment of respiratory tract diseases. In the present work, we investigated the anti-inflammatory and smooth muscle relaxant activities of the hydroalcoholic extract (HAE), coumarin (Coum) and fl avonoid fraction (FF) isolated from the trunk barks of Amburana cearensis A. C. Smith. It was shown that HAE (200 and 400 mg/kg), Coum (20 and 40 mg/kg) and FF (40 mg/kg), administered orally, significantly inhibited both leukocyte and neutrophil migrations, in the carrageenan or N-formyl-methyl-leucyl-phenylalanine (fMLP)-induced migration in rat peritoneal cavity. The increase in cutaneous vascular permeability induced by serotonin in rats was significantly blocked by HAE (150 mg/kg, i.p.), Coum (5 mg/kg, i.p.) and FF (20 mg/kg, i.p.). However, only HAE blocked the histamine effect on Evans blue extravasation. In the guinea-pig trachea precontracted with carbachol (0.3 microM), histamine (0.1 microM) or KCl (0.1 M), the HAE, Coum and FF evoked a concentration-dependent relaxation in the presence of the three agonists. HAE (100-800 microg/ml) and Coum (4-32 microg/ml) also caused significant relaxation of the rat vas deferens previously contracted with adrenaline, acetylcholine or barium chloride. In addition, HAE, Coum and FF inhibited the histamine and serotonin-induced increase of cutaneous vascular permeability in rats.

In vitro dose dependent inverse effect of nantenine on synaptosomal membrane K+-p-NPPase activity.

The effect of nantenine, an aporphine alkaloid, on ATPase K+-dependent dephosphorylation was evaluated using p-nitrophenylphosphate (p-NPP) as substrate. Basal K+-p-NPPase activity was significantly increased with 3 x 10(-4) M, remained unchanged with 3 x 10(-6) M, 3 x 10(-5) M but was reduced with 7.5 x 10(-4) M and 1 x 10(-3) M nantenine, whereas Mg2+-p-NPPase activity was not modified. Kinetic studies showed that K+-p-NPPase inhibition by nantenine is competitive to KCl but non-competitive to substrate p-NPP, whereas K+-p-NPPase stimulation by nantenine is non-competitive to KCl but competitive to p-NPP. These data suggest that there may be two acceptor sites for nantenine in p-NPPase, one eliciting stimulation and the other inhibition of K+-dependent p-NPP hydrolysis. Considering the biphasic action of nantenine on seizures and the correlation between decreased ATPase activity and seizure development, alkaloid anticonvulsant effect observed at low nantenine doses is attributable to the stimulation of phosphatase activity whereas the convulsant effect at high alkaloid doses seems related to Na+, K+-ATPase inhibition.

Nantenine and papaverine differentially modify synaptosomal membrane enzymes.

Papaverine (1-[(3,4-Dimethoxyphenyl) methyl]-6,7-dimethoxyisoquinoline) and nantenine (O-methyldomesticine) are chemically related isoquinoline alkaloids displaying similar dose-dependent sedative or convulsant effects, but seem to act differentially on synaptosomal membrane enzymes. Na+, K+-, Mg2+- and Ca2+-ATPase activities were inhibited by nantenine but not by papaverine, whereas acetylcholinesterase activity remained unchanged by nantenine but slightly enhanced by papaverine. Nantenine inhibited roughly both 20-50% Ca2+- and Mg2+-ATPase activities but 40-90% Na+, K+-ATPase activity. Kinetic analysis indicated that nantenine interacts with the substrate ATP for Ca2+-ATPase activity but that it competes with K+ for Na+, K+-ATPase activity. Given the roles of Na+, K+-ATPase and Ca2+-ATPase in cation transport and [Ca2+]i regulation, respectively, the inhibitory effect of nantenine upon these enzymes may explain its convulsant effect though not its sedative activity. The sedative action of both nantenine and papaverine is hardly attributable to an effect on the synaptosomal membrane enzymes assayed.

Leguminous lectins as tools for studying the role of sugar residues in leukocyte recruitment.

The natural physiological ligands for selectins are oligosaccharides found in glycoprotein or glycolipid molecules in cell membranes. In order to study the role of sugar residues in the in vivo lectin anti-inflammatory effect, we tested three leguminous lectins with different carbohydrate binding affinities in the peritonitis and paw oedema models induced by carrageenin in rats. L. sericeus lectin was more anti-inflammatory than D. virgata lectin, the effects being reversed by their specific binding sugars (N-acetylglucosamine and alpha-methylmannoside, respectively). However, V. macrocarpa, a galactose-specific lectin, was not anti-inflammatory. The proposed anti-inflammatory activity of lectins could be due to a blockage of neutrophil-selectin carbohydrate ligands. Thus, according to the present data, we suggest an important role for N-acetylglucosamine residue as the major ligand for selectins on rat neutrophil membranes.

Antinociceptive and antiedematogenic effects of the hydroalcoholic extract and coumarin from Torresea cearensis Fr. All.

This work studied the antinociceptive and antiedematogenic effects of the hydroalcoholic extract (HAE) and coumarin (Coum) from T. cearensis in experimental models of nociception in mice, and carrageenan- and dextran-induced paw edema in rats. HAE (100 and 200 mg/kg, p.o.) and Coum (5-20 mg/kg, p.o.) reduced in a dose - dependent manner the nociception produced by acetic acid and formalin. In the hot plate test, HAE (100-400 mg/kg, p.o.) and Coum (5 and 10 mg/kg, p.o.) increased the latency time to the thermal stimulus 90 min after administration. While naloxone partially reversed the antinociceptive effect of the HAE but not that of Coum, L-arginine reversed the antinociceptive effect of Coum in the formalin test. HAE (200 mg/kg, p.o.) and Coum (10 and 20 mg/kg, p.o.) significantly inhibited the carrageenan-induced edemas in rats but not the dextran-induced edema. This antiedematogenic effect on the carrageenan model was supported by histological studies performed in sections of the rat paw. In conclusion, the antinociceptive effects of HAE and Coum occur by a mechanism at least in part dependent on the opioid system. The nitric oxide system possibly has also a role in the Coum nociception. In addition, the antiedematogenic activity is manifested in inflammatory processes dependent on polimorphonuclear cells.

Efeito de uma mistura de valepotriatos na resposta de ansiedade induzida em voluntários submetidos a uma situaçäo de estresse psicológico / Effect of valepotriate in the response of induced anxiety in volunteers submitted to a psychological stressing situation

Três grupos de voluntários, após assinatura de um termo de consentimento de participaçäo em experimento, foram submetidos a minucioso exame clínico e complementar de laboratório, bem como a uma entrevista, para se determinar qualquer alteraçäo física ou psíquica que fosse impeditiva de participaçäo no experimento. Receberam, respectivamente, por via oral, placebo, diazepam (5mg) ou Valmane (50mg), em intervalos de 8 horas aproxidamente, iniciando-se o tratamento no dia anterior ao teste, sendo a última dose administrada duas horas antes do procedimento de eliciaçäo de ansiedade, o Stroop-Color Word Test filmado (VRSCWT). A resposta de ansiedade eliciada pela situaçäo foi avaliada pelo Inventário de Ansiedade Traço-Estado de Spielberger. Os valores de ansiedade durante e após a situaçäo de teste, no grupo tratado com Valmane, näo diferiram dos valores-controle ou dos do grupo tratado com diazepam. Os resultados sugerem que o Valmane, na dose utilizada, apresenta, na situaçäo do teste de eliciaçäo de ansiedade, tendência a uma açäo semelhante ao do diazepam, apesar de menos potente. Os resultados mostraram ainda que o diazepam foi eficaz em impedir o aumento de ansiedade eliciado pela situaçäo de teste