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Hot-plate Test (hot-plate + test)
Selected AbstractsRole of Cholecystokinin Receptors in Induction of Antinociception in Hot-Plate TestBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2000Mehdi Rezayat In the present study, the antinociceptive effect of cholecystokinin receptor agonists in the hot-plate test in mice has been evaluated. Subcutaneous administration of cholecystokinin octapeptide (cholecystokinin-8; 0.001, 0.005, 0.01, 0.05, and 0.1 mg/kg), unsulfated cholecystokinin octapeptide (cholecystokinin-8U; 0.1 mg/kg) or caerulein (0.25 mg/kg) produced antinociception. Administration of the cholecystokinin tetrapeptide (cholecystokinin-4; 0.25, 0.5 and 1.0 mg/kg) had no effect in the hot-plate test. Subcutaneous injection of the selective cholecystokinin receptor antagonists, MK-329 (0.125, 0.25 and 0.5 mg/kg) or L-365,260 (0.125, 0.25 and 0.5 mg/kg), produced no antinociceptive response. When the animals were pretreated with the cholecystokinin receptor antagonists or naloxone (0.5 and 1 mg/kg), a significant decrease in the antinociceptive response induced by cholecystokinin-8 and caerulein was obtained. The results indicate that single administration of cholecystokinin receptor agonists could produce an antinociceptive effect which is probably mediated via cholecystokinin receptors. With respect to the results obtained from morphine and naloxone administration, it is concluded that there may be an interaction between cholecystokinin and opiate mechanisms. [source] Inhibition of scratching behaviour caused by contact dermatitis in histidine decarboxylase gene knockout miceEXPERIMENTAL DERMATOLOGY, Issue 3 2005M. Seike Abstract:, A neuronal system dedicated to itch consists of primary afferent and spinothalamic projection neurons. Histamine is thought to be one of the main mediators for the transmission of itch sensation. However, there are little available information on the role of histamine in scratching behaviour and sensory transmission of atopic dermatitis and chronic eczema. In the present study, the role of histamine in scratching behaviour and neural conduction of sensation in the chronic eczema model was investigated by using l-histidine decarboxylase (HDC) gene knockout mice lacking histamine. The chronic contact dermatitis was induced with daily application of diphenylcyclopropenone (DCP) on a hind paw of HDC (+/+) and HDC (,/,) mice for 2 months. The observation of scratching behaviour and the hot-plate test were performed in both mice. Histological studies were performed in the skin and spinal cord tissues. Histological examination revealed that both HDC (+/+) and HDC (,/,) mice displayed the similar extent of inflammatory cell infiltration, hyperplastic epidermis and newly spreading of neuronal processes in the skin tissue. Scratching behaviour was exclusively induced in HDC (+/+) mice, whereas it was barely observed in HDC (,/,) mice. The expression of c-Fos was specifically upregulated in HDC (+/+) mice in lamina I of the spinal dorsal horn following repeated DCP application. Scratching behaviour in chronic contact dermatitis in mice was thought mainly mediated with histamine. The afferent pathway of sensation in chronic contact dermatitis model may connect with the central nervous system through lamina I of the spinal dorsal horn. [source] Hypoalgesia in mice lacking GABA transporter subtype 1JOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2008Yin Fang Xu Abstract ,-Aminobutyric acid (GABA) transporters play a key role in the regulation of GABA neurotransmission. We reported previously that overexpression of the GABA transporter subtype 1 (GAT1), the major form of the GABA transporter in the CNS, led to hyperalgesia in mice. In the present study, nociceptive responses of GAT1-knockout mice (GAT1,/,) were compared with those of heterozygous (GAT+/,) and wild-type (GAT+/+) mice by four conventional pain models (tail-immersion test, hot-plate test, acetic acid,induced abdominal constriction test, and formalin test). In addition, the analgesic effects of two GAT1-selective inhibitors, NO-711 and tiagabine, were examined in all three genotypes using the same four models. Our data demonstrated that GAT1 deficiency because of genetic knockout or acute blockade by selective inhibitors leads to hypoalgesia in mice. These results confirmed the crucial role of GAT1 in the regulation of nociceptive threshold and suggested that GAT1 inhibitors have the potential for clinical use in pain therapy. © 2007 Wiley-Liss, Inc. [source] Antinociceptive and anti-inflammatory effects of the essential oil from Eremanthus erythropappus leavesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2008Orlando V. Sousa The chemical composition of the essential oil from air-dried leaves of Eremanthus erythropappus was studied. The main compounds were ,-pinene (23.24%), ,-caryophyllene (22.92%), ,-myrcene (10.03%) and germacrene D (9.40%). The essential oil had an LD50 of 2.90 gkg,1 in mice. Doses of 200 and 400 mgkg,1 inhibited 10.69% and 27.06% of acetic-acid-induced writhing in mice, respectively. In the formalin-induced nociception test in mice, the essential oil inhibited the first phase of paw licking by 29.13% (400 mgkg,1) and the second phase by 32.74% (200 mgkg,1) and 37.55% (400 mgkg,1). In the hot-plate test in mice, doses of 200 mgkg,1 and 400 mgkg,1 significantly increased the reaction time after 30, 60 and 90 min of treatment. Doses of 200 and 400 mgkg,1 inhibited carrageenan-induced paw oedema in rats by 15.18% and 36.61%, respectively. Doses of 200 and 400 mgkg,1 administered 4 h before intra-pleural injection of carrageenan significantly reduced exudate volume (by 20.20% and 48.70%, respectively) and leucocyte mobilization (by 5.88% and 17.29%, respectively). These results demonstrate that E. erythropappus has analgesic and anti-inflammatory properties, supporting the use of this plant in folk medicine. [source] Anti-inflammatory and analgesic activities of the ethanolic extracts from Zanthoxylum riedelianum (Rutaceae) leaves and stem barkJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2007Leonardo Mandalho Lima We have evaluated the anti-inflammatory and analgesic properties of the leaves (LCE) and stem bark (BCE) crude extracts of Zanthoxylum riedelianum (Rutaceae). Different fractions of the stem bark extract (hexane, BCEH; dichloromethane, BCED; ethyl acetate, BCEE; and lyophilized aqueous residual, BCEW) were also investigated. We studied the effects of the extracts and fractions using the rat paw oedema test induced by carrageenan, dextran, histamine or nystatin; the mouse abdominal constriction test; the mouse hot-plate test (only for LCE and BCE); and the mouse formalin test. Both extracts and all BCE fractions displayed anti-inflammatory activity in the carrageenan-induced oedema model, but not for dextran, histamine or nystatin. Considering the analgesic models, both extracts showed antinociceptive activity, but BCE was more active than LCE in models of central pain. All BCE fractions showed significant inhibition in the abdominal constriction test and in both phases of the formalin test. When BCED was submitted to phytochemical procedures it led to the isolation of six lignans (sesamin, methylpluviatolide, dimethylmatairesinol, piperitol-4,-O-,,,-dimethylallyl ether, kaerophyllin and hinokinin), and a triterpene (lupeol). Inhibition of cyclooxygenase and its metabolites may have been involved in the mechanism of action of this plant, considering previous studies reporting the anti-inflammatory and analgesic activity for the identified lignans, as well as anti-inflammatory activity for lupeol. [source] GABA Mechanisms and Antinociception in Mice with Ligated Sciatic NerveBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2001Mohammad-Reza Zarrindast The response to morphine or GABA receptor agonists was examined 14 days after unilateral nerve ligation by hot-plate test. Intraperitoneal injection of different doses of morphine (3, 6 and 9 mg/kg), muscimol (0.5, 1 and 2 mg/kg) or baclofen (1, 2.5 and 5 mg/kg) induced a dose-related antinociception in both intact and ligated mice. The response of morphine but not that of muscimol or baclofen, in nerve-ligated mice was significantly less than that induced in the intact animals. The responses induced by muscimol or baclofen in nerve-ligated animals, were reduced by bicuculline or CGP35348 [P-(3-aminopropyl)-P-diethoxymethyl-phosphinic acid], respectively. However, morphine in combination with muscimol (2 mg/kg) tends to induce higher response; the combination of the GABA receptor agonists with morphine did not show potentiation, but additive effect. The opioid receptor antagonist naloxone reduced the response induced by muscimol in nerve-ligated animals. It was concluded that although ligation of the sciatic nerve clearly reduced the analgesic effect of morphine and not that of the GABA agonists, the results nevertheless indicated that morphine and the GABAA agonist shared the same mechanism of action. [source] Role of Cholecystokinin Receptors in Induction of Antinociception in Hot-Plate TestBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2000Mehdi Rezayat In the present study, the antinociceptive effect of cholecystokinin receptor agonists in the hot-plate test in mice has been evaluated. Subcutaneous administration of cholecystokinin octapeptide (cholecystokinin-8; 0.001, 0.005, 0.01, 0.05, and 0.1 mg/kg), unsulfated cholecystokinin octapeptide (cholecystokinin-8U; 0.1 mg/kg) or caerulein (0.25 mg/kg) produced antinociception. Administration of the cholecystokinin tetrapeptide (cholecystokinin-4; 0.25, 0.5 and 1.0 mg/kg) had no effect in the hot-plate test. Subcutaneous injection of the selective cholecystokinin receptor antagonists, MK-329 (0.125, 0.25 and 0.5 mg/kg) or L-365,260 (0.125, 0.25 and 0.5 mg/kg), produced no antinociceptive response. When the animals were pretreated with the cholecystokinin receptor antagonists or naloxone (0.5 and 1 mg/kg), a significant decrease in the antinociceptive response induced by cholecystokinin-8 and caerulein was obtained. The results indicate that single administration of cholecystokinin receptor agonists could produce an antinociceptive effect which is probably mediated via cholecystokinin receptors. With respect to the results obtained from morphine and naloxone administration, it is concluded that there may be an interaction between cholecystokinin and opiate mechanisms. [source] Antinociceptive efficacy of levetiracetam in a mice model for painful diabetic neuropathyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2008M. OZCAN Background and Objective: Despite important advances in available knowledge, management of neuropathic pain remains incomplete, and results from experimental and clinical studies indicate that some anticonvulsants show promise for treating neuropathic pain. The aim of this study was to assess the antinociceptive efficacy of levetiracetam (LEV, ucb L059) in a mice model for painful diabetic neuropathy using the in vivo nociceptive behavioral ,hot-plate test.' Methods: The hot-plate test consisted of placing individual mice (adult male Balb/C) on the hot plate at 50±0.1 °C and timing the delay for the first hind paw lift (nociceptive threshold). After obtaining control values, diabetes was induced by injection of streptozotocin [200 mg/kg intraperitoneally (i.p.)] and 2 weeks after induction of diabetes (serum glucose ,400 mg/dL) LEV was administered i.p. and hot-plate tests were repeated. Pain threshold values were determined and analyzed by Kruskal,Wallis one-way analysis of variance (ANOVA) followed by a pairwise comparison using a Dunnett's t -test on the ranked data. Results: LEV (60, 300 and 900 mg/kg) had no significant effect on the nociceptive threshold in normal mice (n=8 for each dose, P>0.05). There were significant decreases in pain threshold latency in diabetic mice compared with the normal healthy group and these were significantly and dose-dependently restored by much lower doses of LEV (20, 100 and 200 mg/kg) in a reversible manner. Conclusion: Results obtained from the in vivo behavioral test lend support to the validation of the promising therapeutic potential of the novel antiepileptic agent LEV in the treatment of neuropathic pain. [source] Antinociceptive Activity of a New Benzofuranone Derived from a ChalconeBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2009Pâmela Padaratz The aim of this work was the synthesis of a new benzofuranone compound and evaluation of its antinociceptive potential in mice. The new benzofuranone 4 was synthesized from chalcone 3. The antinociceptive activity of 4 was determined by writhing, formalin, capsaicin, and glutamate and hot-plate tests. Compound 4 caused potent and dose-related inhibition against the writhing test with ID50 6.1 (5.1,7.6) ,mol/kg, i.p., being about 15 times more active than the reference drugs, acetyl salicylic acid and acetaminophen. It was also effective in a dose-dependent manner in significantly reducing the painful stimulus in both phases of formalin, in the capsaicin and in the glutamate test with ID50 values of 27.3 (24.5,30.6) and 18.9 (18.5,19.4) ,mol/kg (first and second phase), 12.6 (9.8,16.2) and 24.5 (20.4,29.6) ,mol/kg respectively. The results showed that the studied compound exhibits both central and peripheral antinociceptive activities and might be further used as a model to obtain new and more potent analgesic drugs. [source] Morphologic, functional and behavioral effects of titanium dioxide exposure on nervesCLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2004An experimental study on rats Abstract Objectives: The purpose of this study was to explore morphologic, functional, and behavioral effects of titanium dioxide (TiO2) on nerves. Material and methods: A total of 17 albino rats were used for nerve conduction experiments, hot-plate tests, and histological evaluation. TiO2 was implanted unilaterally on the sciatic nerves of five rats. Ten days after surgery, test and control nerves were dissected and their signal transduction speeds were quantified by suction electrodes in a bath containing a Tyrode solution. Twelve rats were divided into three equal groups resulting in equal number of nerves (n=8) for TiO2 implantation, surgical exposure of the nerves, and for use as controls. One week after surgery, hot-plate tests were undertaken for 10 consecutive days to determine response latencies of the nerves. At the termination of the experiments, the nerves were harvested, processed, and examined under a microscope. Results: The signal transduction speeds of TiO2 -implanted nerves was similar to control specimens (P>0.05). The avoidance responses of TiO2 -implanted, surgically exposed, and control nerves were comparable (P>0.05). At the cellular level, TiO2 did not lead to any signs of adverse reactions on nerves. Conclusions: TiO2, the main oxide surrounding endosseous titanium implants, does not alter the structure and the function of myelinated nerves. Résumé Le but de cette étude a été d'explorer les effets morphologiques, du comportement, de la fonction du dioxide de titane (TiO2) sur les nerfs. Dix-sept rats albinos ont été utilisés pour ces expériences de comportement nerveux, des tests en culture et l'évaluation histologique. Le TiO2 a été implanté unilatéralement sur les nerfs sciatiques de cinq rats. Dix jours après la chirurgie, les nerfs tests et contrôles ont été disséqués et leur vitesse de transduction du signal ont été quantifiée par des électrodes de succion dans un bain contenant une solution de thyrode. Douze rats ont été répartis en trois groupes égaux résultant en un nombre égal de nerfs (n=8) pour l'implantation de TiO2, l'exposition chirurgicale des nerfs et pour l'utilisation comme contrôle. Une semaine après la chirurgie, des tests de culture ont été effectués durant dix jours d'affilée pour déterminer les temps de latence de réponse des nerfs. A la fin des expériences, les nerfs ont été prélevés et examinés sous microscope. Les vitesses de transduction du signal des nerfs où il y avait implantation de TiO2 étaient semblables aux contrôles (P>0.05). Les réponses de manquement des nerfs contrôles, chirurgicalement exposés et implantés TiO2 étaient semblables (P>0.05). Au niveau cellulaire, le TiO2 n'entraînait pas d'effets secondaires sur les nerfs. Le dioxyde de titane, l'oxyde principal entourant les implants titane endoosseux n'altère ni la structure ni la fonction des nerfs myélinisés. Zusammenfassung Ziel: Es war das Ziel dieser Studie, morphologische und funktionelle Verhaltensänderungen eines Nerven als direkte Reaktion auf Titandioxid (TiO2) zu untersuchen. Material und Methode: Man verwendete für Versuche bezüglich Reizleitung der Nerven, für den Kochplattentest und für histologische Untersuchungen insgesamt 17 Albinoratten. Zuerst implantierte man bei fünf Ratten einseitig TiO2 direkt auf den Ischiasnerven. 10 Tage nach der Chirurgie resezierte man die Test- und die Kontrollnerven, legte sie in ein Bad mit Tyrodelösung und mass mit Saugelektroden die Leitgeschwindigkeit eines Signals. Die 12 übrigen Ratten teilte man auf drei gleichgrosse Gruppen auf und erhielt somit je acht Nerven (n=8) für die Implantation von TiO2, die chirugische Entblössung oder für die Kontrollgruppe. Eine Woche nach der Chirurgie führte man an 10 aufeinanderfolgenden Tagen den Kochplattentest durch, um Verzögerungen der Nervenreaktion zu messen. Nach Abschluss dieser Untersuchung entnahm man die Nerven, bereitete sie histologisch auf und untersuchte sie anschliessend unter dem Mikroskop. Resultate: Die Leitgeschwindigkeit eines Signals beim Nerven mit implantiertem TiO2 war ganz ähnlich wie bei den Kontrollnerven (P>0.05). Die Abwehrreaktion von Nerven mit implantiertem TiO2, von chirurgisch entblössten Nerven und von Kontrollnerven war vergleichbar (P>0.05). Auf zellulärer Ebene führte TiO2 zu keiner Abwehrreaktion der Nerven. Zusammenfassung: Titandioxid, anteilsmässig das häufigste Oxid auf enossalen Implantaten, verändert weder Struktur noch Funktion von myelinisierten Nerven. Resumen Objetivos: El propósito de este estudio fue explorar los efectos morfológicos, funcionales y de comportamiento del dióxido de titanio (TiO2) sobre los nervios. Material y métodos: Se usaron un total de 17 ratas albinas para experimentos de conducción nerviosa, pruebas de plato caliente, y evaluación histológica. Se implantó TiO2 unilateralmente en los nervios ciáticos de cinco ratas. 10 días tras la cirugía, se disecaron los nervios de prueba y de control y se cuantificaron sus velocidades de transducción de señales por electrodos de succión en un baño conteniendo solución tiroidea. Se dividió a 12 ratas en tres grupos iguales resultando en igual numero de nervios (n=8) para implantación de TiO2, exposición quirúrgica de los nervios y para usarlos de control. Una semana tras la cirugía, se llevaron a cabo pruebas de plato caliente durante 10 días consecutivos para determinar las latencias de respuesta de los nervios. A la terminación de los experimentos, los nervios se recolectaron, se procesaron y se examinaron bajo el microscopio. Resultados: Las velocidades de transducción de señales de los nervios implantados de TiO2 fueron similares a las de los especímenes de control (P>0.05). Las respuestas de huida de los nervios implantados de TiO2, expuestos quirúrgicamente, y los nervios de control fueron comparables (P>0.05). A nivel celular, el TiO2 no condujo a ningún signo de reacciones adversas en los nervios. Conclusiones: El dióxido de titanio, el óxido principal que rodea a los implantes endoóseos de titanio, no altera la estructura ni la función de los nervios mielínicos. [source] | ||||||||||