Chez les vertébrés, la douleur est perçue par des neurones spécialisés, les nocicepteurs, dont le corps cellulaire est localisé dans les ganglions de la racine dorsale (DRG) et qui présentent une grande hétérogénéité. Nous cherchons donc à identifier de nouveaux marqueurs des sous populations de nocicepteurs afin de pouvoir comprendre cette diversité et d’attribuer des fonctions physiologiques précises à ces différentes sous-populations neuronales. Nous avons identifié le gène GINIP, spécifiquement exprimé dans une sous populations de nocicepteurs non peptidergiques et définissant deux classes particulières de neurones : les neurones MRGPRD+ et les C-Low Threshold MecanoReceptors (C-LTMRs). Durant ma thèse, j’ai cherché à savoir quelles modalités sensorielles sont détectées et transmises par la population GINIP+. Pour cela, j’ai tiré avantage d’un modèle murin ginip généré au laboratoire, permettant d’éliminer spécifiquement les neurones GINIP+ au sein des neurones du DRG. J’ai pu démontrer que l’ablation ciblée de ces neurones entraine une diminution de la douleur induite par l’injection de formaline, cela sans affecter la sensibilité thermique ou mécanique. Sachant que les neurones MRGPRD positifs ne sont pas impliqués dans la réponse douloureuse induite par l’injection de formaline, mais jouent un rôle primordial dans la mécano sensibilité en condition normale et pathologique, notre étude montre que la réponse douloureuse induite par l’injection de formaline est due à l’activation des C-LTMRs. En conclusion, notre étude révèle que les C-LTMRs agissent en tant que puissants modulateurs des douleurs chimiques et mécaniques. / Primary sensory neurons are heterogeneous by myriad of molecular criteria. However, the functional significance of this remarkable heterogeneity is just emerging. Here we used our recently generated ginip mouse model to selectively ablate the cutaneous free nerve endings MRGPRD+ neurons and the C-Low threshold mechanoreceptors (C-LTMRs). Ablation of GINIP-expressing neurons led to a significant decrease of formalin-evoked first pain and a complete absence of the second phase pain response, without affecting thermal or mechanical sensitivity. Knowing that MRGPRD+ neurons are dispensable for formalin-evoked pain and that these neurons play a critical role in acute and injury-induced mechanical pain, our data demonstrate that formalin-induced pain hypersensitivity is primarily transduced via C-LTMRs, and suggest that C-LTMRs and MRGPRD+ neurons play antagonistic roles in transduction of acute and injury-induced mechanical pain. Therefore, our results suggest that C-LTMRs act as strong modulators of chemical and mechanical pain signals.

The present study explored the antinociceptive effects of H3 (R-alpha-methylhistamine) and GABAB (baclofen) receptor ligands in an orofacial model of pain in rats. Orofacial pain was induced by subcutaneous injection of formalin (50 μl, 5 %) in the upper lip region, and the number of jumps and time spent face rubbing was recorded for 40 min. Formalin produced a marked biphasic pain response; first phase, 0-10 min (jumps), and second phase, 15-40 min, (rubbing). Baclofen (50 μg) injected into the rat wiskerpad 5 min before formalin administration suppressed both phases of pain whereas R-alpha-methylhistamine (12.5 μg) abolished the first phase only. Brains were taken immediately after behavioral testing was completed. HPLC/ED analysis showed that 5-hydroxytryptamine (5-HT) turnover was increased in hippocampus, thalamus, and brain stem of all formalin groups, excepting the baclofen group in which the balance of 5-HT metabolism was restored to control values. These findings demonstrate that GABAB receptors represent peripheral targets for analgesia. Consequently, locally administered baclofen may be a useful approach in treating inflammatory trigeminal pain.

The present study explored the antinociceptive effects of H3 (R-alpha-methylhistamine) and GABAB (baclofen) receptor ligands in an orofacial model of pain in rats. Orofacial pain was induced by subcutaneous injection of formalin (50 μl, 5 %) in the upper lip region, and the number of jumps and time spent face rubbing was recorded for 40 min. Formalin produced a marked biphasic pain response; first phase, 0-10 min (jumps), and second phase, 15-40 min, (rubbing). Baclofen (50 μg) injected into the rat wiskerpad 5 min before formalin administration suppressed both phases of pain whereas R-alpha-methylhistamine (12.5 μg) abolished the first phase only. Brains were taken immediately after behavioral testing was completed. HPLC/ED analysis showed that 5-hydroxytryptamine (5-HT) turnover was increased in hippocampus, thalamus, and brain stem of all formalin groups, excepting the baclofen group in which the balance of 5-HT metabolism was restored to control values. These findings demonstrate that GABAB receptors represent peripheral targets for analgesia. Consequently, locally administered baclofen may be a useful approach in treating inflammatory trigeminal pain.

An ultra-low dose of a drug is approximately 1000-fold lower than the dose range traditionally used to induce a therapeutic effect. The purpose of the present thesis was to broaden the knowledge of the ultra-low dose effect, that was previously identified in the opioid receptor system, by looking at whether opioids and cannabinoids interact at the ultra-low dose level, whether cannabinoid receptors themselves demonstrate the ultra-low dose antagonist effect, and whether the opioid ultra-low dose effect is maintained in a model of persistent, unavoidable pain. For experiment 1, separate groups of Long Evans rats were tested for antinociception following an injection of vehicle, the cannabinoid agonist WIN 55 212-2 (WIN), the opioid antagonist naltrexone (an ultra-low or a high dose), or a combination of WIN and naltrexone doses. Ultra-low dose naltrexone elevated WIN-induced tail flick thresholds without extending its duration of action. In experiment 2, antinociception was tested in rats following either acute or sub-chronic (7 days) injections of vehicle, WIN, ultra-low doses of the CB1 receptor antagonist rimonabant (SR 141716), or a combination of WIN and ultra-low dose rimonabant. Following the chronic experiment, striatal tissue was rapidly extracted and subjected to co-immunoprecipitation to analyse CB1 receptor coupling to G-protein subtypes. Ultra-low dose rimonabant extended the duration of WIN-induced antinociception, and attenuated the development of WIN-induced tolerance. Animals chronically treated with WIN alone had CB1 receptors predominately coupling to Gs proteins, whereas all other groups had CB1 receptors predominately coupling to Gi proteins. For experiment 3, all animals were subjected to the formalin test following either acute or sub-chronic injections of vehicle, the opiate morphine, ultra-low doses naltrexone, or a combination of morphine and ultra-low dose naltrexone. Ultra-low dose naltrexone had no significant effect on morphine-induced pain ratings in either the acute, or sub-chronic drug treatments. This thesis provides evidence that the ultra-low dose effect, including the agonist-induced G-protein coupling switch, extends to another receptor type. This effect may, therefore, be part of a generalized principle that applies to many G-protein coupled receptors. / Thesis (Ph.D, Psychology) -- Queen's University, 2007-11-05 09:31:30.162 / A portion of this research was supported by a Canadian Institutes of Health Research (CIHR) Proof of Principle Grant to M.C. Olmstead and J.J. Paquette.

Orientadores: Claudia Herrera Tambeli, Maria Cecilia F. A. Veiga / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-03T22:56:59Z (GMT). No. of bitstreams: 1 Clemente-Napimoga_JulianaTrindade_M.pdf: 904782 bytes, checksum: 55d51f81e2ba465f145751f287246951 (MD5) Previous issue date: 2004 / Resumo: Este estudo avaliou as diferenças sexuais na resposta nociceptiva induzida pela administração de formalina na articulação temporomandibular (ATM) com ou sem a co-administração do U50,488 (agonista do receptor opióide capa). As fases do ciclo estral das fêmeas foram citologicamente determinadas e apenas aquelas que apresentavam-se na fase diestro ou proestro, e machos foram incluídos. A formalina induziu um comportamento nociceptivo maior nas fêmeas em diestro do que nas fêmeas em proestro ou machos. O U50,488 reduziu significativamente as respostas nociceptivas induzidas pela formalina, e esta redução foi maior nas fêmeas, especialmente nas fêmeas da fase diestro do ciclo estral. A injeção do U50,488 na ATM contralateral não afetou na magnitude do comportamento induzido pela formalina, e o pré-tratamento com o antagonista seletivo do receptor opióide capa nor-binaltorphimine (norBNI) na ATM ipsilateral reduziu os efeitos antinociceptivos do U50,488. Estes resultados demonstram a ação dos receptores opióides capa periféricos na modulação da dor inflamatória. Além disso, considerando que os níveis plasmáticos dos hormônios ovarianos são baixos durante a fase diestro, estes resultados são consistentes com a hipótese de que os hormônios sexuais femininos podem ter uma ação analgésica na redução da dor inflamatória induzida pela formalina, assim como, também ter uma ação anti-analgésica nos efeitos mediados pelos receptores opióides capa / Abstract: This study examined sex differences in nociceptive responses induced by intra-temporomandibular joint (TMJ) formalin with and without co-administration of the ?-opioid receptor agonist U50,488. The estrous phase of females was cytologically determined; only those in either proestrus or diestrus, and males, were included. Formalin elicited significantly greater nociceptive behavior in diestrus females than in either proestrus females or males. U50,488 significantly reduced formalin nociceptive responses, and this reduction was significantly greater in females, especially in the diestrus phase of the estrous cycle. U50,488 injection into the contralateral TMJ failed to affect the magnitude of formalininduced behavior, and preinjection of the selective kappa-opioid receptor antagonist nor-binaltorphimine (nor-BNI) into the ipsilateral TMJ significantly reduced the antinociceptive effect of U50,488. These findings support a role for peripheral kappa-opioid receptors in the modulation of inflammatory pain. Furthermore, since plasma levels of ovarian hormones are lowest during diestrus, these findings are consistent with the suggestion that female sex hormones may play an analgesic role in reducing formalin-induced inflammatory pain, and may also play an anti-analgesic role, at least in ?-mediated effects / Mestrado / Fisiologia Oral / Mestre em Odontologia

Um estudo prévio de nosso grupo de pesquisa demonstrou que uma fração eriquecida em valepotriatos obtida a partir de partes aéreas e subterrâneas de V. glechomifolia submetida à extração com CO2 supercrítico (VAL) possui efeito antidepressivo e prevenção do comportamento de doente (sickness behavior) induzido por LPS. Além disso, alguns estudos revelaram propriedades antiinflamatórias de V.wallichii e de V.amurensis. Estes dados da literatura sugerem que os valepotriatos podem ser utilizados no desenvolvimento de novos farmácos. Entretanto, dados sobre toxicidade, segurança e atividade anti-inflamatória de valepotriatos ainda são escassos. Considerando isso, o objetivo deste estudo foi investigar a atividade anti-inflamatória periférica e a toxicidade oral aguda e de doses repetidas de VAL. A atividade anti-inflamatória foi avaliada por meio do teste de formalina em camundongos CF1 e o ensaio de migração de leucócitos em ratos Wistar. Além disso, os estudos de toxicidade seguiram as normativas 423 e 407 da Organização para a Cooperação e Desenvolvimento Econômico (OECD). Diferentes grupos de camundongos foram tratados com VAL (1, 10 e 30 mg/kg), diclofenaco 50 mg/kg (controle positivo) ou saline (controle negativo) 1 h antes da injeção de formalina. No ensaio de quimiotaxia, os leucócitos foram tratados com concentrações de 0,1-1,0 μg/mL de VAL, indometacina ou diclofenaco (1 μg/mL). No estudo de toxicidade aguda, três camundongos CF1 machos foram tratados com uma dose única de VAL (2000 mg/kg, v.o.) e observados durante 14 dias. Já para o estudo de toxicidade de doses repetidas, diferentes grupos de animais (n = 10) receberam doses únicas diárias de VAL (30, 150 e 300 mg/kg, v.o.) ou veículo durante 28 dias. No teste de formalina, VAL inibiu o comportamento do tipo nociceptivo na segunda fase do teste de forma dose-dependente. O efeito da dose mais elevada de VAL foi comparável com o diclofenaco na dose de 50 mg/kg (v.o.). VAL (0,1-1 μg/mL) também inibiu a migração de leucócitos induzida por LPS (65 μg/mL) de modo dependente da concentração. Este efeito foi comparável ao efeito de indometacina (0,1 - 1 μg/mL) e superior ao efeito do diclofenaco (1 μg/mL). No estudo de toxicidade aguda apenas uma morte foi detectada, o que classifica VAL como segura (categoria 5), de acordo com a OECD-normativa 423. O estudo toxicidade de doses repetidas demonstrou que VAL na dose de 300 mg/kg retardou o ganho de peso e reduziu o consumo de ração dos animais deste grupo na primeira semana de tratamento, provavelmente devido aos efeitos sedativos da mesma. As outras doses não alteraram o ganho de peso e ingesta de ração. Nenhuma das doses de VAL alterou qualquer parâmetro comportamental, urinário, bioquímico, hematológico, anatômico ou histológico. Em conclusão, estes resultados demonstram pela primeira vez que valepotriatos, uma classe especial de terpenos que ocorrem apenas no gênero Valeriana, apresentam atividade anti-inflamatória periférica e são seguros em doses pré-clínicas eficazes, por via oral. / A previous study by our research group demonstrated that an enriched fraction obtained from the aerial and subterranean parts of V. glechomifolia submitted to supercritical CO2 extraction (VAL) shows antidepressant-like effect and prevented LPS-induced sickness behavior. Also, some studies revealed anti-inflammatory properties of V.wallichii and V.amurensis. Altogether, these findings suggest that the valepotriates scaffold might be useful to develop new antidepressant and antiinflammatory drugs. However, data about the toxicity, safety and anti-inflammatory activity of valepotriates from V. gelchomifolia are still scarce. Considering this, the aim of this study was to investigate the peripheral anti-inflammatory activity and the oral acute and repeated toxicity of VAL. The anti-inflammatory activity was assessed by using the formalin test in CF1 mice and Wistar rat’s leukocytes migration assay. Besides, the toxicity studies followed the Organization for Economic Cooperation and Development (OECD) toxicity studies guidelines 423 and 407. Different groups of mice were treated with VAL (1, 10 and 30 mg/kg), diclofenac 50 mg/kg (positive control) or saline (negative control) 1 h before the formalin injection. In the chemotaxis assay, the leukocytes were treated with a range of 0.1-1.0 μg/mL of VAL, indomethacin or diclofenac (1 μg/mL). In the acute toxicity, three CF1 mice were treated with a single dose of VAL (2000 mg/kg, p.o.) and observed for 14 days. To perform the repeated toxicity study, separated group of animals (n=10) received single daily doses of VAL (30, 150 and 300 mg/kg, p.o.) or vehicle during 28 days. In the formalin test, VAL inhibited the nociceptive behavior in the late phase in a dose dependent manner at 30mg/kg dose. The effect of the VAL highest dose was comparable to diclofenac 50 mg /kg (p.o.). VAL (0.1 - 1 μg/mL) inhibited the leukocyte migration induced by LPS (65 μg/mL) in a concentration dependent manner. This antichemotatic effect was comparable to indomethacin (0.1 – 1μg/mL) and better than diclofenac (1 μg/mL) effect. In the acute toxicity study only one death was detected, which classify VAL as safe (category 5), according to OECD-guideline 423. The repeated dose toxicity study demonstrated that VAL 300 mg/kg delayed the weight gain and reduced the food consumption in the first week, probably due to sedative effects. The other doses had no effect on weight gain and food consumption. None of doses altered any behavioral, urinary, biochemical, hematological, anatomic or histological parameters. In conclusion, these results demonstrate for the first time that valepotriates, a special class of terpenes occurring only in Valeriana genus, present peripheral anti-inflammatory activity and are safe at effective pre-clinical doses, by oral route.

In this thesis, rodent models of chronic pain were used to explore analgesic mechanisms that may potentially be engaged in spinal and peripheral compartments by systemically-administered amitriptyline, a tricyclic antidepressant. The first project (Chapter 2) identified the roles of spinal adenosine A1 and serotonin 5-HT7 receptors, as well as of peripheral adenosine A1 receptors, in the acute antinociceptive effects of amitriptyline in mice. The second project (Chapter 3) examined the potential utility of amitriptyline as a preventive analgesic against persistent post-surgical pain, and involved perioperative administration of amitriptyline after peripheral nerve injury in rats. Changes in post-injury behavioural outcomes, as well as spinal noradrenergic sprouting, were assessed. Overall, spinal serotonergic pathways linked to adenosine A1 receptors, as well as peripheral adenosine A1 receptors, appear to be important in antinociception by amitriptyline. Preventive analgesia by this drug does not appear to result from anatomical changes in spinal noradrenergic pathways.

Um estudo prévio de nosso grupo de pesquisa demonstrou que uma fração eriquecida em valepotriatos obtida a partir de partes aéreas e subterrâneas de V. glechomifolia submetida à extração com CO2 supercrítico (VAL) possui efeito antidepressivo e prevenção do comportamento de doente (sickness behavior) induzido por LPS. Além disso, alguns estudos revelaram propriedades antiinflamatórias de V.wallichii e de V.amurensis. Estes dados da literatura sugerem que os valepotriatos podem ser utilizados no desenvolvimento de novos farmácos. Entretanto, dados sobre toxicidade, segurança e atividade anti-inflamatória de valepotriatos ainda são escassos. Considerando isso, o objetivo deste estudo foi investigar a atividade anti-inflamatória periférica e a toxicidade oral aguda e de doses repetidas de VAL. A atividade anti-inflamatória foi avaliada por meio do teste de formalina em camundongos CF1 e o ensaio de migração de leucócitos em ratos Wistar. Além disso, os estudos de toxicidade seguiram as normativas 423 e 407 da Organização para a Cooperação e Desenvolvimento Econômico (OECD). Diferentes grupos de camundongos foram tratados com VAL (1, 10 e 30 mg/kg), diclofenaco 50 mg/kg (controle positivo) ou saline (controle negativo) 1 h antes da injeção de formalina. No ensaio de quimiotaxia, os leucócitos foram tratados com concentrações de 0,1-1,0 μg/mL de VAL, indometacina ou diclofenaco (1 μg/mL). No estudo de toxicidade aguda, três camundongos CF1 machos foram tratados com uma dose única de VAL (2000 mg/kg, v.o.) e observados durante 14 dias. Já para o estudo de toxicidade de doses repetidas, diferentes grupos de animais (n = 10) receberam doses únicas diárias de VAL (30, 150 e 300 mg/kg, v.o.) ou veículo durante 28 dias. No teste de formalina, VAL inibiu o comportamento do tipo nociceptivo na segunda fase do teste de forma dose-dependente. O efeito da dose mais elevada de VAL foi comparável com o diclofenaco na dose de 50 mg/kg (v.o.). VAL (0,1-1 μg/mL) também inibiu a migração de leucócitos induzida por LPS (65 μg/mL) de modo dependente da concentração. Este efeito foi comparável ao efeito de indometacina (0,1 - 1 μg/mL) e superior ao efeito do diclofenaco (1 μg/mL). No estudo de toxicidade aguda apenas uma morte foi detectada, o que classifica VAL como segura (categoria 5), de acordo com a OECD-normativa 423. O estudo toxicidade de doses repetidas demonstrou que VAL na dose de 300 mg/kg retardou o ganho de peso e reduziu o consumo de ração dos animais deste grupo na primeira semana de tratamento, provavelmente devido aos efeitos sedativos da mesma. As outras doses não alteraram o ganho de peso e ingesta de ração. Nenhuma das doses de VAL alterou qualquer parâmetro comportamental, urinário, bioquímico, hematológico, anatômico ou histológico. Em conclusão, estes resultados demonstram pela primeira vez que valepotriatos, uma classe especial de terpenos que ocorrem apenas no gênero Valeriana, apresentam atividade anti-inflamatória periférica e são seguros em doses pré-clínicas eficazes, por via oral. / A previous study by our research group demonstrated that an enriched fraction obtained from the aerial and subterranean parts of V. glechomifolia submitted to supercritical CO2 extraction (VAL) shows antidepressant-like effect and prevented LPS-induced sickness behavior. Also, some studies revealed anti-inflammatory properties of V.wallichii and V.amurensis. Altogether, these findings suggest that the valepotriates scaffold might be useful to develop new antidepressant and antiinflammatory drugs. However, data about the toxicity, safety and anti-inflammatory activity of valepotriates from V. gelchomifolia are still scarce. Considering this, the aim of this study was to investigate the peripheral anti-inflammatory activity and the oral acute and repeated toxicity of VAL. The anti-inflammatory activity was assessed by using the formalin test in CF1 mice and Wistar rat’s leukocytes migration assay. Besides, the toxicity studies followed the Organization for Economic Cooperation and Development (OECD) toxicity studies guidelines 423 and 407. Different groups of mice were treated with VAL (1, 10 and 30 mg/kg), diclofenac 50 mg/kg (positive control) or saline (negative control) 1 h before the formalin injection. In the chemotaxis assay, the leukocytes were treated with a range of 0.1-1.0 μg/mL of VAL, indomethacin or diclofenac (1 μg/mL). In the acute toxicity, three CF1 mice were treated with a single dose of VAL (2000 mg/kg, p.o.) and observed for 14 days. To perform the repeated toxicity study, separated group of animals (n=10) received single daily doses of VAL (30, 150 and 300 mg/kg, p.o.) or vehicle during 28 days. In the formalin test, VAL inhibited the nociceptive behavior in the late phase in a dose dependent manner at 30mg/kg dose. The effect of the VAL highest dose was comparable to diclofenac 50 mg /kg (p.o.). VAL (0.1 - 1 μg/mL) inhibited the leukocyte migration induced by LPS (65 μg/mL) in a concentration dependent manner. This antichemotatic effect was comparable to indomethacin (0.1 – 1μg/mL) and better than diclofenac (1 μg/mL) effect. In the acute toxicity study only one death was detected, which classify VAL as safe (category 5), according to OECD-guideline 423. The repeated dose toxicity study demonstrated that VAL 300 mg/kg delayed the weight gain and reduced the food consumption in the first week, probably due to sedative effects. The other doses had no effect on weight gain and food consumption. None of doses altered any behavioral, urinary, biochemical, hematological, anatomic or histological parameters. In conclusion, these results demonstrate for the first time that valepotriates, a special class of terpenes occurring only in Valeriana genus, present peripheral anti-inflammatory activity and are safe at effective pre-clinical doses, by oral route.

Um estudo prévio de nosso grupo de pesquisa demonstrou que uma fração eriquecida em valepotriatos obtida a partir de partes aéreas e subterrâneas de V. glechomifolia submetida à extração com CO2 supercrítico (VAL) possui efeito antidepressivo e prevenção do comportamento de doente (sickness behavior) induzido por LPS. Além disso, alguns estudos revelaram propriedades antiinflamatórias de V.wallichii e de V.amurensis. Estes dados da literatura sugerem que os valepotriatos podem ser utilizados no desenvolvimento de novos farmácos. Entretanto, dados sobre toxicidade, segurança e atividade anti-inflamatória de valepotriatos ainda são escassos. Considerando isso, o objetivo deste estudo foi investigar a atividade anti-inflamatória periférica e a toxicidade oral aguda e de doses repetidas de VAL. A atividade anti-inflamatória foi avaliada por meio do teste de formalina em camundongos CF1 e o ensaio de migração de leucócitos em ratos Wistar. Além disso, os estudos de toxicidade seguiram as normativas 423 e 407 da Organização para a Cooperação e Desenvolvimento Econômico (OECD). Diferentes grupos de camundongos foram tratados com VAL (1, 10 e 30 mg/kg), diclofenaco 50 mg/kg (controle positivo) ou saline (controle negativo) 1 h antes da injeção de formalina. No ensaio de quimiotaxia, os leucócitos foram tratados com concentrações de 0,1-1,0 μg/mL de VAL, indometacina ou diclofenaco (1 μg/mL). No estudo de toxicidade aguda, três camundongos CF1 machos foram tratados com uma dose única de VAL (2000 mg/kg, v.o.) e observados durante 14 dias. Já para o estudo de toxicidade de doses repetidas, diferentes grupos de animais (n = 10) receberam doses únicas diárias de VAL (30, 150 e 300 mg/kg, v.o.) ou veículo durante 28 dias. No teste de formalina, VAL inibiu o comportamento do tipo nociceptivo na segunda fase do teste de forma dose-dependente. O efeito da dose mais elevada de VAL foi comparável com o diclofenaco na dose de 50 mg/kg (v.o.). VAL (0,1-1 μg/mL) também inibiu a migração de leucócitos induzida por LPS (65 μg/mL) de modo dependente da concentração. Este efeito foi comparável ao efeito de indometacina (0,1 - 1 μg/mL) e superior ao efeito do diclofenaco (1 μg/mL). No estudo de toxicidade aguda apenas uma morte foi detectada, o que classifica VAL como segura (categoria 5), de acordo com a OECD-normativa 423. O estudo toxicidade de doses repetidas demonstrou que VAL na dose de 300 mg/kg retardou o ganho de peso e reduziu o consumo de ração dos animais deste grupo na primeira semana de tratamento, provavelmente devido aos efeitos sedativos da mesma. As outras doses não alteraram o ganho de peso e ingesta de ração. Nenhuma das doses de VAL alterou qualquer parâmetro comportamental, urinário, bioquímico, hematológico, anatômico ou histológico. Em conclusão, estes resultados demonstram pela primeira vez que valepotriatos, uma classe especial de terpenos que ocorrem apenas no gênero Valeriana, apresentam atividade anti-inflamatória periférica e são seguros em doses pré-clínicas eficazes, por via oral. / A previous study by our research group demonstrated that an enriched fraction obtained from the aerial and subterranean parts of V. glechomifolia submitted to supercritical CO2 extraction (VAL) shows antidepressant-like effect and prevented LPS-induced sickness behavior. Also, some studies revealed anti-inflammatory properties of V.wallichii and V.amurensis. Altogether, these findings suggest that the valepotriates scaffold might be useful to develop new antidepressant and antiinflammatory drugs. However, data about the toxicity, safety and anti-inflammatory activity of valepotriates from V. gelchomifolia are still scarce. Considering this, the aim of this study was to investigate the peripheral anti-inflammatory activity and the oral acute and repeated toxicity of VAL. The anti-inflammatory activity was assessed by using the formalin test in CF1 mice and Wistar rat’s leukocytes migration assay. Besides, the toxicity studies followed the Organization for Economic Cooperation and Development (OECD) toxicity studies guidelines 423 and 407. Different groups of mice were treated with VAL (1, 10 and 30 mg/kg), diclofenac 50 mg/kg (positive control) or saline (negative control) 1 h before the formalin injection. In the chemotaxis assay, the leukocytes were treated with a range of 0.1-1.0 μg/mL of VAL, indomethacin or diclofenac (1 μg/mL). In the acute toxicity, three CF1 mice were treated with a single dose of VAL (2000 mg/kg, p.o.) and observed for 14 days. To perform the repeated toxicity study, separated group of animals (n=10) received single daily doses of VAL (30, 150 and 300 mg/kg, p.o.) or vehicle during 28 days. In the formalin test, VAL inhibited the nociceptive behavior in the late phase in a dose dependent manner at 30mg/kg dose. The effect of the VAL highest dose was comparable to diclofenac 50 mg /kg (p.o.). VAL (0.1 - 1 μg/mL) inhibited the leukocyte migration induced by LPS (65 μg/mL) in a concentration dependent manner. This antichemotatic effect was comparable to indomethacin (0.1 – 1μg/mL) and better than diclofenac (1 μg/mL) effect. In the acute toxicity study only one death was detected, which classify VAL as safe (category 5), according to OECD-guideline 423. The repeated dose toxicity study demonstrated that VAL 300 mg/kg delayed the weight gain and reduced the food consumption in the first week, probably due to sedative effects. The other doses had no effect on weight gain and food consumption. None of doses altered any behavioral, urinary, biochemical, hematological, anatomic or histological parameters. In conclusion, these results demonstrate for the first time that valepotriates, a special class of terpenes occurring only in Valeriana genus, present peripheral anti-inflammatory activity and are safe at effective pre-clinical doses, by oral route.

Made available in DSpace on 2016-06-02T19:22:05Z (GMT). No. of bitstreams: 1 3116.pdf: 11974848 bytes, checksum: d69698c04f669985473e9e441c532444 (MD5) Previous issue date: 2009-12-11 / Universidade Federal de Sao Carlos / In innate or learned threatening situations, animals display a set of defensive behaviors specie-specific such as autonomic alterations, flight, fight and antinociception. Exposure of mice to open elevated plus-maze (oEPM: four open arms), an aversive situation, elicits antinociception of high magnitude. However, mechanisms involved in this kind of antinociception are not clear yet. This study investigated whether antinociception induced by exposure to an oEPM shows cross-tolerance with morphine (Exp. I and II); is attenuated by repetead exposure to the oEPM (Exp. III); is blocked by systemic treatment with naltrexone (Exp. IV); is prevented by adrenalectomy (Exp. V); persists after animal removal from the oEPM and if there are sex-related differences in this factor (Exp. VI); is mediated by CB1 cannabinoid receptor (Exp. VII). Rats were daily treated with morphine (M, 5 mg/kg, i.p.) or distilled water (DW) for 5 consecutive days (antinociceptive tolerance assessed by the tailflick test). Next day, rats received formalin 2.5% injection (50 μL) into the right hind paw and, after first phase of formalin test, they were treated with M or DW. 25 minutes after formalin injection into the paw, time spent licking the injected paw was recorded for 10 minutes (Exp. 1). Similar procedure was followed in the Experiment II, except that time spent licking the paw was recorded during exposure to the oEPM or enclosed EPM (eEPM: four arms enclosed) in undrugged rats. In Experiment III, nociception was evaluated in rats submitted to 1, 2, 3, 4 or 6 exposures to either eEPM or oEPM (formalin was injected only during the last exposure). Experiment IV investigated the effects of naltrexone (0 and 2.5 mg/kg; s.c.) on nociception during eEPM or oEPM exposure. Nociception was also assessed during the eEPM or oEPM exposure in sham and adrenalectomized rats (exp. V). In experiment VII, rats were treated with vehicle (DMSO 60%) or AM251 (1 mg/kg, i.p., CB1 receptor antagonist). Fifteen minutes later, animals received formalin injection into the paw and, 25 minutes after, they were exposed to the eEPM or oEPM. In experiment VI, male and female rats were exposed to eEPM or oEPM (with no noxious stimulus during exposure) and imediately after they were tested on the hot plate test (52.4 °C). Results showed that antinociception induced by oEPM does not display cross-tolerance to morphine; was not altered for at least 6 exposures to the maze; failed to be reversed by naltrexone; was not prevented by adrenalectomy and was not blocked by AM251. In addition, this antinociception does not persist after animal removal of the apparatus, by contrast, it occurs a hyperalgesia (as assessed by hot plate test), a response that does not depend on sex-related differences. Results suggest that antinociception induced by oEPM: is not mediated by opioid system or CB1 cannabinoid receptors and it is not sensitive to corticosterone. Furthermore, animal removal of aversive environment alters nociceptive response from antinociception to hyperalgesia, a phenomenon that is independent of the gender. / Em situações ameaçadoras de natureza inata ou aprendida, animais exibem um conjunto de comportamentos defensivos espécie-específicos, tais como alterações autonômicas, fuga, luta e antinocicepção. A exposição de camundongos ao labirinto em cruz elevado aberto (LCEa: quatro braços abertos), uma situação aversiva, induz antinocicepção de alta magnitude. Todavia, os mecansimos envolvidos em tal antinocicepção ainda não estão elucidados. O presente estudo investigou se a antinocicepção induzida por exposição ao LCEa: mostra tolerância cruzada a morfina (experimentos I e II); é atenuada por exposição repetida ao LCEa (experimento III); é revertida por tratamento sistêmico com naltrexona (experimento IV); é impedida por adrenalectomia (experimento V); persiste após remoção do animal do LCEa e se há diferenças relacionadas ao sexo neste fator (experimento VI); é mediada pelo receptor canabinóide, CB1 (experimento VII). Ratos foram diariamente tratados com morfina (M, 5 mg/Kg, i.p.) ou água destilada (AD) por 5 dias consecutivos (tolerância antinociceptiva avaliada pelo teste de retirada da cauda). No dia seguinte, os ratos receberam injeção de formalina 2,5% (50L) na pata traseira direita e, após a primeira fase do teste de formalina, foram tratados com M ou AD. Vinte e cinco minutos após injeção de formalina na pata, o tempo de lambidas na pata foi registrado por 10 minutos (experimento I). Procedimento semelhante foi utilizado no experimento II, exceto que o tempo de lambidas na pata foi registrado durante exposição ao LCEa ou LCE fechado (LCEf: quatro braços fechados). No experimento III, nocicepção foi avaliada em ratos submetidos a 1, 2, 3, 4 ou 6 exposições ao LCEf ou LCEa (formalina injetada somente durante a última exposição). O experimento IV investigou os efeitos de naltrexona (2,5 mg/kg; s.c.) sobre a nocicepção durante exposição ao LCEf ou LCEa. A nocicepção também foi avaliada durante exposição ao LCEf ou LCEa em ratos sham operados e adrenalectomizados (experimento V). No experimento VII, os ratos foram tratados com veículo (DMSO 60%) ou AM251 (1 mg/kg, i.p., antagonista CB1). Quinze minutos após, os animais receberam formalina na pata e, após 25 minutos, foram expostos ao LCEf ou LCEa. Já no experimento VI, ratos machos e fêmeas foram expostos ao LCEf ou LCEa, sem nenhum estímulo nociceptivo aplicado durante exposição e, imediatamente após, foram testados no teste da placa quente (52,4 °C). Os resultados mostraram que a antinocicepção induzida pelo LCEa não exibe tolerância cruzada a morfina; não foi alterada por ao menos 6 exposições ao labirinto; mostrou-se insensível à naltrexona; não foi impedida por adrenalectomia e não foi bloqueada por AM251. Ainda, tal antinocicepção não perdura após remoção dos animais do aparelho, pelo contrário, ocorre uma hiperalgesia (conforme avaliado pelo teste de placa quente), uma resposta que independe de diferenças relacionadas ao sexo. Os resultados sugerem que a antinocicepção induzida pelo LCEa: não é mediada por sistema opióide ou receptores canabinóides CB1 e não é sensível a corticosterona. Além disso, a retirada dos animais do ambiente aversivo altera a resposta nociceptiva de antinocicepção para hiperalgesia, um fenômeno que independe do gênero.