ENZYMATIC REGULATION OF OPIOID ANTINOCICEPTION AND TOLERANCE By Lynn C. Hull, Ph.D. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Virginia Commonwealth University, 2009 Director: William L. Dewey, Ph.D. Department of Pharmacology and Toxicology The involvement of kinases in opioid actions has long been established. The acute actions of opioids, through the Gi/Go G-proteins, cause the inhibition of adenylyl cyclase and therefore a decrease in protein kinase A (PKA) activation. Additionally, acute opioid administration may cause the G-protein to activate the phospholipase C (PLC)-mediated cascade leading to the activation of protein kinase C (PKC). The phosphorylation of the MOR which can lead to both desensitization by uncoupling of the G-protein coupled receptors (GPCRs) from the G-proteins and to internalization by recruitment of β-arrestins has long been identified as a key process in tolerance. Phosphorylation by PKA and PKC leads primarily to uncoupling of the receptor from the G-proteins. Phosphorylation of the receptor by G-protein coupled receptor kinase (GRK) leads to the recruitment of β-arrestins and internalization of the receptor. Many in vitro studies have come to the conclusion that GRK induced internalization plays a more central role in the tolerance to high efficacy opioids and a lesser role in low- and moderate-efficacy opioid tolerance. In fact it has been hypothesized that morphine, a moderate-efficacy opioid, causes no internalization at all, while the desensitization of the receptor via phosphorylation by PKA and PKC plays a more central role in low- and moderate-efficacy opioid tolerance. We sought to test these in vitro findings in an in vivo model of opioid tolerance. Animals were made tolerant to one of a number of opioids of varying efficacy (low-efficacy meperidine, moderate-efficacy morphine and fentanyl, and high-efficacy [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO)) over an 8 hour period and then were administered one of the kinases’ inhibitors. Tolerance reversal was determined by challenging these mice with the same opioids to which they were tolerant. Calcium is known to play an important role in the acute antinociceptive actions of opioids as well as in opioid tolerance. Therefore it is important to determine how opioids are affecting the regulation of intracellular calcium. Our laboratory has previously shown that Calcium Induced Calcium Release (CICR), the ryanodine receptor and intracellular microsomal Ca2+ pools all play a role in opioids’ actions. It is also well known that mammalian ADP-ribosyl cyclase, CD38’s, product cADPR acts on the ryanodine receptor to cause Ca2+ release into the intracellular space. We chemically and genetically altered CD38 and then tested the acute effect of morphine as well as what effect these treatments had on morphine tolerance to determine what role if any, that CD38 may play in the acute actions of morphine antinociception as well as in morphine tolerance. Together, studies focusing on the role of an ADP-ribosyl cyclase, CD38, and 3 separate kinases, PKA, PKC and GRK, in opioids’ actions were performed in order to better understand the roles of these enzymes’ pathways in the actions of opioid-induced antinociception and subsequent development of tolerance. It is hoped that the results herein add useful knowledge to the general understanding of this drug class, and will one day be of use in the development of future analgesics and in the clinical treatment of pain and reduction in tolerance.

Cannabinoids produce antinociception in many preclinical models of acute and chronic pain. In contrast, cannabinoids produce inconsistent analgesia in humans, showing little or no efficacy in treating acute pain, with modest efficacy in treating chronic inflammatory pain. This discrepancy may reflect an overreliance on preclinical assays of pain-stimulated behaviors, defined as behaviors that increase in rate or intensity following delivery of a noxious stimulus. In these assays, antinociception is indicated by a reduction in pain-stimulated behaviors, and antinociception is produced either by a reduction in sensory sensitivity to the noxious stimulus (i.e. true analgesia) or by false positive motor impairment. This dissertation addresses this weakness by complementing cannabinoid effects in conventional assays of pain-stimulated behavior with their effects in novel assays of pain-depressed behavior. Pain-depressed behaviors are defined as behaviors that decrease in rate or intensity following presentation of a noxious stimulus. Motor impairment does not produce false positive antinociception in assays of pain-depressed behavior, because antinociception is indicated by a blockade or reversal of pain-induced behavioral depression. In this dissertation, an intraperitoneal (IP) injection of lactic acid served as an acute noxious stimulus to stimulate stretching (pain-stimulated behavior) or depress intracranial self-stimulation (ICSS) (pain-depressed behavior), whereas, IP injection(s) of lipopolysaccharide (LPS) served as a chronic/acute inflammatory-related noxious stimulus to stimulate mechanical allodynia (pain-stimulated behavior) or depress ICSS (pain-depressed behavior). Cannabinoids tested in the assays of acid-stimulated stretching and acid-depressed ICSS included: mixed CB1R/CB2R agonists THC and CP55940, drugs that modulate levels of the endogenous cannabinoid agonist anandamide (URB597 and PF3845), and a selective CB2R agonist, GW405833. THC was also tested in assays of LPS-stimulated mechanical allodynia and LPS-depressed ICSS. In general, mixed CB1R/CB2R agonists were ineffective or exacerbated pain-depressed behavior regardless of noxious stimulus. Contrastingly, URB597 and GW405833 produced antinociception in the assay of acid-depressed ICSS; however their effects were not mediated by CBRs. All compounds produced antinociception in the assay of pain-stimulated behavior, except for PF3845. These results suggest that assays of pain-depressed behavior may be useful for development of cannabinoid analgesic medications, but that further research is needed to determine mechanisms underlying cannabinoid-mediated antinociception in these assays.

Currently, there is an increasing need for novel analgesics that are potent but lack undesired side effects. Recent studies have shown that both 5-HT3 receptors and α2B- adrenoceptors play a role in antinociception. MD-354, N-(3-chlorophenyl)guanidine, has a high-affinity both for 5-HT3 and α2B- adrenoceptors and could be viewed as the first example of a rather selective 5-HT3/α2B- adrenoceptor ligand. MD-354, inactive by itself, potentiates the antinociceptive effects of an inactive dose of clonidine in the mouse tail- flick assay. An attempt to determine the underlying mechanism of this potentiating effect was the purpose of the present investigation. The studies focused on an examination of: i) MD-354 in the mouse hot-plate assay, ii) a more lipophilic analog of MD-354 in the tail-flick assay, iii) various analogs of MD-354 with different binding profiles in both mouse tail-flick and hot-plate assays. The present investigation suggests that both 5-HT3 and α2B- adrenoceptors are playing a role in the potentiation of clonidine analgesia by arylguanidines such as MD-354. Arylguanidines might represent a unique class of analgesia-enhancing agents with a dual (5-HT3/α2- adrenoceptor) mechanism of action.

Quando confrontado com situações de medo os roedores apresentam respostas comportamentais (ex., luta, fuga, imobilidade e vocalização) e neurovegetativas (taquicardia, hipertensão e defecação) que caracterizam a reação de defesa. Em geral essas respostas são acompanhadas de antinocicepção. Estudos demonstram um papel do óxido nítrico (NO) e de receptores NMDA (N-metil-D-aspartato) na mediação de respostas nociceptivas no corno dorsal da medula espinal. Resultados do nosso laboratório demonstraram que a exposição a uma situação ameaçadora, como o labirinto em cruz elevado aberto ou sem paredes (LCEa), provoca antinocicepção de alta magnitude em ratos e camundongos. Assim, o presente estudo teve por objetivo investigar o papel do complexo receptor glutamato/NMDA e NO no corno dorsal da medula espinal na resposta antinociceptiva induzida pela exposição ao LCEa. Camundongos receberam injeção por via intratecal (i.t.) de NMDA (0; 0,4 ou 0,8 nmol/5,0 l) para avaliar seus efeitos intrínsecos sobre a nocicepção. Enquanto a dose de 0,8 nmol de NMDA provocou efeitos nociceptivos, a dose de 0,4 nmol se mostrou desprovida de efeitos. Em seguida, nosso estudo avaliou os efeitos do NMDA (0; 0,1; 0,2 ou 0,4 nmol, i.t.) na nocicepção induzida pela injeção de formalina 2,5% na pata traseira direita do camundongo. Nenhuma dose de NMDA aumentou o tempo de lambidas na pata durante os 10 minutos do teste. Assim, investigamos os efeitos da injeção i.t. de NMDA (0; 0,1; 0,2 ou 0,4 nmol) na antinocicepção induzida pela exposição ao ambiente aversivo (LCEa) ou não aversivo (LCE fechado: quatro braços com paredes; LCEf) em camundongos pré-tratados com formalina a 2,5% na pata traseira direita, durante 10 minutos. O tratamento com NMDA (0,4 nmol) reverteu parcialmente a antinocicepção induzida pela exposição ao LCEa, sem afetar a resposta dos animais expostos ao LCEf. Para avaliar se os efeitos anti-antinociceptivos do NMDA (0,4 nmol) dependem da síntese de NO, camundongos receberam injeção i.t. combinada de L-NAME (N-nitro-L-arginina-metil-éster), um inibidor da NOS, e NMDA. O pré-tratamento com L-NAME (40 nmoles/5,0 l i.t.) bloqueou seletivamente os efeitos anti-antinociceptivos do NMDA. Tomados em conjunto, nossos resultados sugerem que a antinocicepção induzida pela exposição ao LCEa pode ser parcialmente revertida pela ativação de receptores NMDA e indicam que esse efeito depende da síntese de NO no corno dorsal da medula espinal de camundongos. / Rodents exposed to threatening situations (e.g., prey-predator interactions) usually display defensive behaviors (e.g., fight, flight, freezing, vocalization), and neurovegetative (e.g., tachycardia, hypertension, defecation) responses characterized as a fear reaction. Commonly, these responses are accompanied by antinociception. Evidence showing that the glutamate NMDA (N-methyl-d-aspartate) receptor and nitric oxide (NO) complex located within the dorsal horn of the spinal cord in the mediation of the nociceptive response have instigated researchers to investigate the role of the NMDA/NO on some types of fear-induced antinociception. This study investigated the role of the glutamate-NMDA receptor complex and NO in the dorsal horn of the spinal cord of mice in the antinociception induced by a potentially aversive situation, i.e., an exposure to an open elevated plus maze (oEPM: four open arms). Mice were intrathecally (i.t.) injected with N-methyl-D-aspartic acid (NMDA: 0, 0.4 or 0.8 nmol/5.0 l) to assess its intrinsic effects upon nociception. Results showed that NMDA at 0.8 nmol, but not at 0.4 nmol, was able to induce intrinsic nociceptive effect. When injected in animals pre-treated with formalin 2.5% into the right hind paw (nociceptive test), NMDA (0, 0.1, 0.2 or 0.4 nmol, i.t.) did not change time spent licking the formalin injected paw. Then, we investigated the effects of NMDA injection (0, 0.1, 0.2 or 0.4 nmol, i.t.) on nociceptive response induced by formalin test in mice exposed to the oEPM (aversive situation) or enclosed EPM (eEPM: four enclosed arms; control situation) for 10 minutes. NMDA treatment (0.4 nmol) partially reversed the antinociception induced by oEPM exposure without affect nociception in mice exposed to the eEPM. Finally, we investigated whether the anti-antinociceptive effect of NMDA would be dependent on NO synthesis by injecting L-NAME (N-nitro-L-arginine-methyl-ester) i.t., a inhibitor of NOS (nitric oxide synthase), 10 minutes before NMDA injection. L-NAME pretreatment (40 nmol/5.0 l; i.t.) selectivelly blocked anti-antinociceptive effect of NMDA 0.4 nmol. Taken together, our results suggest that antinociception induced by oEPM exposure (i) is, at least in part, reversed by NMDA receptors activation and (ii) this NMDA effect seems to be dependent on NO synthesis within the dorsal horn of the spinal cord in mice.

O tramadol é um analgésico de ação central amplamente utilizado em répteis. Seu efeito ocorre por meio da ativação de receptores opioides e do bloqueio da recaptação de serotonina e norepinefrina. Este estudo objetivou avaliar a atividade antinociceptiva e a farmacocinética do tramadol em jabutis-piranga. Oito jabutis receberam quatro tratamentos, com intervalo mínimo de 21 dias: solução salina (grupo controle), tramadol nas doses de 5 mg/kg (TIM5) e 10 mg/kg (TIM10) por via intramuscular e 5 mg/kg (TIV5) por via intravenosa. Um estímulo nociceptivo térmico foi aplicado na superfície plantar dos animais e a avaliação da latência do reflexo de retirada do membro foi realizada nos tempos 0, 30 minutos, 1, 2, 4, 6, 8, 10, 24, 48, 72 e 96 horas. Foi realizada também colheita de sangue e análise do plasma por meio de cromatografia gasosa acoplada à espectrometria de massas triplo quadrupolo. A farmacocinética do tramadol foi calculada por abordagem não-compartimental. A concentração máxima para TIM5 e TIM 10 foi de 128,98 ± 59,46 ng/mL e 613,87 ± 524,26 ng/mL, respectivamente. A meia-vida de eliminação foi de 21,22 ± 8,74 horas para TIV5, 32,84 ± 6,41 horas para TIM5 e 22,5 ± 8,02 horas para TIM10. As doses de tramadol 10 mg/kg por via intramuscular e 5 mg/kg por via intravenosa não apresentaram alteração do tempo de latência para o reflexo de retirada do membro. O grupo que recebeu 5 mg/kg por via intramuscular apresentou diferença nos tempos 1 hora e 24 horas após a administração. O tramadol não apresentou efeito antinociceptivo consistente por via intramuscular nas doses de 5 e 10 mg/kg e por via intravenosa na dose de 5 mg/kg em jabutis-piranga. Independente da via de administração, o tramadol apresentou meia-vida de eliminação longa. / Tramadol is a centrally acting analgesic widely used in reptiles. It promotes activation of opioid receptors and inhibits serotonin and norepinephrine reuptake. This study aimed to evaluate the antinociceptive effects and pharmacokinetics of tramadol in red-footed tortoises. Eight animals were treated with four different protocols, with a 3-week washout period: saline IM (control group), tramadol 5 mg/kg IM (TIM5) and 10 mg/ kg IM (TIM10) and 5 mg/kg IV (TIV5). Infrared heat stimuli was applied to the plantar surface of the animals and thermal withdrawal latencies were measured at 0 and 30 minutes, 1, 2, 4, 6, 8, 10, 24, 48, 72 and 96 hours after drug treatment. Blood samples were obtained and plasma analysis performed by gas chromatography - triple quadrupole tandem mass spectrometry. Pharmacokinetics parameters were determined using non-compartimental equations. The average peak drug concentration was 128.98 ± 59.46 ng/mL (TIM5) and 613.87 ± 524.26 ng/mL (TIM10). The elimination half-life was 21.22 ± 8.74 hours (TIV5), 32.84 ± 6.41 hours (TIM5) and 22.5 ± 8.02 hours (TIM10). TIM10 and TIV5 showed no changes in thermal withdrawal latencies. TIM5 showed a significant increase in thermal withdrawal latencies at 1 hour and 24 hours after administration. Tramadol did not induce a consistent antinociceptive effect at 5 mg/kg and 10 mg/kg IM and ar 5 mg/kg IV in red-footed tortoises. Regardless of the route of administration, tramadol had a long half-life and plasma concentrations close to those reported in other species.

A atribuição da percepção da dor pelos peixes é um assunto controverso no meio científico. Alguns autores associam a percepção da dor a estruturas neocorticais que estão ausentes em peixes. Entretanto, estudos recentes têm demonstrado que os peixes são capazes de perceber e responder a estímulos nocivos de maneira semelhante ao que é observado em mamíferos, sendo estas respostas sensíveis à administração de morfina. Além disso, estudos pioneiros de nosso laboratório demonstraram a existência de um sistema analgésico endógeno em peixes. O objetivo deste estudo foi avaliar se este sistema analgésico endógeno pode ser ativado pelo estresse. A natureza neuroquímica deste sistema e a participação de uma região telencefálica, o telencéfalo dorsomedial (Dm), na modulação da antinocicepção também foram investigados. Nossos dados demonstram que o estresse de restrição de 3 e 5 minutos de duração inibe a resposta comportamental à injeção subcutânea de formalina a 3% na região da nadadeira adiposa no peixe Leporinus macrocephalus, sugerindo que este procedimento é capaz de ativar um sistema antinociceptivo endógeno. Além disso, a antinocicepção induzida pelo estresse de restrição de 3 e 5 min é de curta duração, sendo observada apenas por 5 min após o término da restrição. A análise da natureza neuroquímica da antinocicepção induzida pelo estresse de restrição revelou participação do sistema opióde e canabinoide na modulação desta resposta. O tratamento prévio com injeção intraperitoneal de naloxona (30 mg.kg-1), um antagonista opioide não seletivo, bloqueou a antinocicepção induzida pela restrição de 3 min de duração, mas não foi capaz de inibir a antinocicepção induzida pela restrição de 5 min de duração. Já o tratamento prévio com injeção intraperitoneal de AM251 (3 mg.kg-1), um antagonista de receptores canabinoides tipo 1, bloqueou a antinocicepção induzida pelo estresse de restrição de 3 e 5 min de duração, sugerindo que o sistema canabinoide desempenha um papel fundamental na antinocicepção induzida por esta modalidade de estresse na espécie estudada. Nosso estudo também demonstrou que a região do telencéfalo dorsomedial está envolvida na modulação da antinocicepção induzida pelo estresse de restrição no peixe L. macrocephalus. A microinjeção de midazolan (40 e 80 nmol), um agonista de receptores benzodiazepínicos, no telencéfalo Dm bloqueou a antinocicepção induzida pela restrição de 3 e 5 min de duração. Além disso, o tratamento prévio com flumazenil (80 e 160 nmol), um antagonista específico de receptores benzodiazepínicos, inibiu os efeitos do tratamento com midazolan, demonstrando que o bloqueio da antinocicepção promovido pelo midazolan ocorre pela ativação específica dos receptores benzodiazepínicos. Juntos estes resultados trazem novas perspectivas acerca do entendimento sobre a percepção nociceptiva em peixes. Este é o primeiro trabalho que traz evidências acerca da existência de um sistema de modulação da dor ativado pelo estresse e demonstra a participação de uma região encefálica específica na modulação desta antinocicepção. Estes resultados indicam que as vias analgésicas endógenas em peixes são ativadas de maneira semelhante aos mamíferos, sugerindo que estes animais possuem um processamento complexo da informação nociceptiva. / The assignment of pain perception by fish is controversial among scientists. Some authors associate the pain perception to neocortical structures that are absent in fish. However, recent studies have shown that fish are able to perceive and respond to noxious stimuli, similar to observed in mammals, and this responses are sensitive to morphine administration. Furthermore, pioneering studies from our laboratory have demonstrated the existence of an endogenous analgesic system in fish. This study aimed to evaluate if this endogenous analgesic system can be activated by stress, the neurochemical nature of this system and involvement of a telencephalic region, the dorsomedial (Dm) telencephalon, in the antinociception modulation. Our data demonstrate that 3 and 5 min of restraint stress inhibits the behavioral response to subcutaneous injection of formalin 3 % in the adipose fin in the fish Leporinus macrocephalus, suggesting that this procedure can activate an endogenous antinociceptive system. Furthermore, stress-induced antinociception induced by 3 and 5 min of restraint is short, with the antinociceptive effects being observed only for 5 min after the restriction. The analysis of the neurocheamical nature of antinociception induced by restraint stress revealed the involvement of opioid and cannabinoid systems in the modulation of this response. The pre-treatment with intraperitoneal injection of naloxone (30 mg.kg-1), a non-selective opioid receptors antagonist, blocked the antinociception induced by 3 min of restraint, but was not able to inhibit the antinociception induced by 5 min of restraint. The pre-treatment with intraperitoneal injection of AM251 ( 3 mg.kg-1), a type 1 cannabinoid receptors antagonist, blocked the stress-induced antinociception promoted by 3 and 5 min of restraint, suggesting that the cannabinoid system plays a critical role in this type of stress-induced antinociception in the studied species. Our study also showed that the dorsomedial telencephalon is involved in the modulation of stress-induced antinociception in fish L. macrocephalus. The microinjection of midazolan (40 and 80 nmol), a benzodiazepine receptors agonist, in the Dm blocked the stress-induced antinociception promoted by 3 and 5 min of restraint. Furthermore, pre-treatment with flumazenil (80 and 160 nmol), a benzodiazepine receptors selective antagonist, inhibited the effects of the midazolan treatment, demonstrating that the antinociception blockade by midazolan is promoted by specific activation of benzodiazepine receptors. Together these results provide new insights on the understanding of nociceptive perception in fish. This is the first study that demonstrates evidence for the existence of a pain modulation system activated by stress in fish and demonstrates the involvement of a specific brain region in the modulation of this antinociception. These results indicate that the endogenous analgesic pathways in fish are activated in a similar manner to mammals, suggesting that these animals have a complex processing of nociceptive information.

A popularização dos répteis no mercado pet e no meio científico amplia a necessidade por conhecimentos clínicos e fisiológicos mais adequados a classe o que, consequentemente, irá melhorar a qualidade dos atendimentos e do manejo desses animais. Destaca-se que, como cada espécie de réptil apresenta um comportamento metabólico e fisiológico distinto é necessário a realização de estudos com cada espécie em particular. Assim, buscou-se caracterizar os receptores opioides no sistema nervoso central (SNC) e os efeito sedativo e analgésico da morfina e do butorfanol em Iguana iguana. Na 1ª etapa três iguanas jovens (101 ± 6g) e saudáveis foram submetidas à eutanásia para colheita do SNC. Os tecidos de dois animais foram submetidos à técnica do RNAseq para formação de um transcriptoma de novo, para então obter-se as sequências de nucleotídeos dos receptores opioides. Já o tecido de um animal foi submetido à técnica de imuno-histoquímica (IH). Na 2ª etapa, 10 iguanas jovens (160 ± 46g) receberam cinco tratamentos, por via intramuscular e com intervalo de duas semanas entre eles: solução salina (0,3mL, CON), morfina 5 mg/kg (MOR5) e 10 mg/kg (MOR10), butorfanol 5 mg/kg (BUT5) e 10 mg/kg (BUT10). A sedação foi avaliada por meio da escala comportamental específica para iguanas e pelo teste de natação forçada, sendo este por 120 segundos. A latência do reflexo de retirada do membro (LRRM) frente ao estímulo térmico foi utilizada para avaliação antinociceptiva promovida pelos opioides. Todos os testes foram avaliados antes do tratamento (0) e com 30 minutos, 1, 2, 3, 4, 6, 12 e 24 horas pós-tratamento. Utilizou-se ANOVA e Dunnett para a comparação com o momento basal (0 minuto) e ANOVA de dois fatores e Tukey entre os grupos. As sequências gênicas compatíveis com os receptores μ (mu), κ (kappa) e δ (delta) foram identificadas, porém o teste de IH não revelou resultados confiáveis para as marcações dos receptores no SNC. Na escala comportamental apesar dos escores de sedação terem sido baixos, foi observado aumento significativo na pontuação entre 30 minutos e 2 horas em MOR5 e entre 30 minutos e 3 horas em MOR10, BUT5 e BUT10. O tempo de natação foi reduzido em MOR10 e BUT5 entre 30 minutos e 2 horas e em BUT10 a redução ocorreu entre 30 minutos e 12 horas. Todos os tratamentos proporcionaram sedação pelos dois testes com 12 horas de avaliação. Por outro lado no teste de termoalgimetria só foi observado aumento no tempo de LRRM em MOR10, entre 2 horas e 4 horas de avaliação. Conclui-se que os receptores opioides estão presentes no SNC, porém apenas κ e δ foram evidenciados na IH. Ademais, as duas doses de butorfanol e a maior dose de morfina promovem sedação, sendo que apenas 10 mg/kg de morfina promoveu antinocicepção em iguanas no presente estudo. / The increasing popularity of reptiles in the pet market and in the scientific studies requires appropriate clinical and physiological knowledge, which will consequently improve the quality of care and management of this classe. It is necessary to have studies with each species in particular because of every specie of reptile has different metabolic and physiological behavior. Therefore, it was aimed localization of opioid receptor in the central nervous system (CNS) and evaluated the sedative and analgesic effect of morphine and butorphanol in Iguana iguana. At the first stage three young (101 ± 6g) and healthy green iguanas were submitted to euthanasia for harvesting the CNS, then the tissues of two animals were submitted to the RNAseq technique for the formation of de Novo transcriptome, so we could get the nucleotide sequences of the opioid receptors obtained. The immunohistochemistry (IH) technique was use to locate the distribution of these receptors in the CNS. In the second stage, 10 young green iguanas (160 ± 46 g) received five treatments, intramuscularly and with an interval of two weeks between them: saline solution (0.3 mL, CON), morphine 5 mg/kg (MOR5) and 10 mg/kg (MOR10), butorphanol 5 mg/kg (BUT5) and 10 mg/kg (BUT10). The sedation was estimate by behavioral scale for iguanas and forced swing test, during 120 seconds. The latency of hind limb withdrawal reflex (LWR) in front of the thermal stimulus was use for antinociceptive evaluation promoted by opioids. All the tests were evaluate before treatment (0) and at 30 minutes, 1, 2, 3, 4, 6, 12 and 24 hours post-treatment. ANOVA and Dunnett were used for comparison with the baseline (0 minute) and two-way ANOVA and Tukey between the groups. We identified sequences compatible with μ (mu), κ (kappa) and δ (delta), but only κ and δ were marked in the IH of the CNS. In the behavior scale despite of low scores of sedation, it was observe a significant increase in the score between 30 minutes and 2 hour MOR5 and between 30 minutes and 3 hours in MOR10, BUT5 and BUT10. The time of swimming test was reduced in MOR10 and BUT5 between 30 minutes and 2 hours and in BUT10 the reduction occurred between 30 minutes and 12 hours. All treatment provided sedation for both tests in 12 hours of evaluation. Otherwise, the thermoalgymetry test showed increased time in LWR in MOR10 between 2 hours and 4 hours of evaluation. It concluded that the opioid receptors are present in the CNS. In addition, the two doses of butorphanol and the highest dose of morphine further sedation and only 10 mg/kg of morphine promoted antinociception in iguanas in this study.

Submitted by Verena Bastos (verena@uefs.br) on 2015-07-24T13:45:42Z No. of bitstreams: 1 ?UDER REIS DIAS -DISSERTA??O MESTRADO 2013 -RGV.pdf: 1805178 bytes, checksum: fa9b0a71b8366540b825499da5adb0f8 (MD5) / Made available in DSpace on 2015-07-24T13:45:42Z (GMT). No. of bitstreams: 1 ?UDER REIS DIAS -DISSERTA??O MESTRADO 2013 -RGV.pdf: 1805178 bytes, checksum: fa9b0a71b8366540b825499da5adb0f8 (MD5) Previous issue date: 2013-10-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The Melastomataceae family comprises 4,570 species in approximately 180 genera present in all tropical and subtropical regions of the planet. This family, in Brazil, is the sixth largest family of Angiosperms, with over 1500 species. The genus Tibouchina presents, approximately, 350 species, however, are poorly studied. The Tibouchina pereirae Aubl., a shrub, is popularly used for the treatment of kidney diseases. In this study, we show the antioxidant and antinociceptive effects of T. pereirae. The hexane (EHTP), ethanol (EETP) and aqueous (EATP) extracts were obtained by maceration from the aerial parts of T. pereirae. The flavonoid rich fraction (FFTP) was obtained from fractionation of EHTP. The analysis of FFTP by HPLC-DAD and HPLC-MS/MS led to characterization of these flavonoids. The antioxidant activity of extracts was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay system and the in vivo experiments were conducted on Swiss mice using the acetic acid-induced writhing test and the formalin-induced pain test. Results showed that extracts (EHTP, EETP and EATP) and FFTP present antioxidant activity, when compared to standard butylated hydroxytoluene (BHT) and ascorbic acid (AA). The EHTP and FFTP (i.p., 100mg/Kg) reduced the nociception produced by acetic acid by 90,36% and 94,74%, respectively. The FFTP reduced the formalin effects in both phases by 54, 35% and 92,05%, while the EHTP only protected the second phase by 83,39%. / A fam?lia Melastomataceae apresenta cerca de 4.570 esp?cies, distribu?das em, aproximadamente, 180 g?neros presentes em todas as regi?es tropicais e subtropicais do planeta, sendo que no Brasil ? a sexta maior fam?lia de angiospermas, com mais de 1500 esp?cies. O g?nero Tibouchina possui aproximadamente 350 esp?cies, por?m s?o muito pouco estudadas, sendo que a esp?cie Tibouchina pereirae Aubl. ? popularmente utilizada para o tratamento de problemas renais. Nesse estudo, foram avaliadas as atividades antioxidante e antinociceptiva de T. pereirae. Foram obtidos os extratos hex?nico (EHTP), etan?lico (EETP) e aquoso (EATP) a partir da macera??o das partes a?reas de T. pereirae. A fra??o rica em flavonoides (FFTP) foi obtida a partir do fracionamento do EHTP. A an?lise por CLAE-DAD e CLAE-EM/EM desta fra??o possibilitou caracterizar estes flavonoides. A atividade antioxidante dos extratos foi avaliada utilizando o sistema de ensaio 2,2-difenil-1-picrilhidrazil (DPPH) e os experimentos in vivo foram realizados em camundongos Swiss utilizando os testes de contor??o abdominal induzida por ?cido ac?tico e da formalina. Os resultados obtidos demonstraram que o EHTP, EETP e EATP, assim como a fra??o FFTP apresentaram atividade seq?estradora radicalar, quando comparados aos padr?es butilhidroxitolueno (BHT) e ?cido asc?rbico (AA). O EHTP e a FFTP reduziram a nocicep??o induzida pelo ?cido ac?tico em 90,6% e 94,74%, respectivamente. A FFTP reduziu os efeitos da formalina em ambas fases em 54,35% e 92,05%, respectivamente, enquanto que o EHTP foi ativo somente na segunda fase do teste, com uma redu??o no tempo de lambida de 83,39%.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Lectinas de algas marinhas tÃm-se mostrado importantes ferramentas biotecnolÃgicas. Objetivou-se estudar as atividades antinociceptivas e antiinflamatÃrias da lectina da alga marinha vermelha Pterocladiella capillacea (Pc). A Pc, apresentando atividade hemaglutinante contra eritrÃcitos tripsinizados de coelho, foi obtida a partir da aplicaÃÃo do extrato protÃico total em cromatografia de troca iÃnica em coluna de DEAE-celulose seguida da cromatografia de afinidade em coluna de goma de guar. A seguir, foi utilizada nos ensaios de nocicepÃÃo e inflamaÃÃo, utilizando camundongos machos Swiss e ratos machos Wistar, respectivamente. Pc (0,9; 8,1 ou 72,9 mg/kg; i.v) foi administrada 30 min antes de cada estÃmulo nocigÃnico, ou seja, antes da injeÃÃo i.p de Ãcido acÃtico a 0,8% (10 &#956;L/mL), da injeÃÃo intraplantar de formalina a 1% (20 &#956;L/pata) ou do teste da Placa quente (51Â1 ÂC), e comparada a animais nÃo tratados ou prÃ-tratados com Indometacina ou Morfina, ambas a 5 mg/kg; s.c. Observou-se que a Pc (0,9; 8,1 ou 72,9 mg/kg) reduziu significantemente o nÃmero de contorÃÃes abdominais induzidas pelo Ãcido acÃtico em 29,2%; 39,3%, e 51,9%, respectivamente. Pc (72,9 mg/kg) tambÃm reduziu (p<0,05) a fase 1 (neurogÃnica) e a fase 2 (inflamatÃria) observadas apÃs administraÃÃo da formalina, em 58% e 87%, respectivamente. Entretanto, a Pc (72,9 mg/kg) nÃo foi capaz de reduzir a nocicepÃÃo observada no teste da Placa Quente, quando comparada à morfina. Os efeitos antinociceptivos da Pc foram abolidos quando a Pc foi prÃ-incubada com a glicoproteÃna mucina (1,25 mg/mL), inibidora de sua atividade hemaglutinante. Sugere-se, portanto, que a atividade antinociceptiva da Pc possa ser predominante via inibiÃÃo de mecanismos perifÃricos. Assim, seguiram-se os ensaios de induÃÃo da migraÃÃo neutrofÃlica para cavidade peritoneal ou do edema de pata de ratos por Carragenana (Cg-tipo l; 500 g/cavidade ou pata), onde observou-se que a administraÃÃo da Pc (8,1 mg/kg; i.v) 30 min antes da Cg reduziu significativamente a contagem do nÃmero de neutrÃfilos em 84%. No entanto, a Pc nÃo foi capaz de prevenir o edema de pata induzido pela Cg. Desta forma, sugere-se que esta proteÃna foi capaz de reduzir o mecanismo de migraÃÃo de neutrÃfilos, possivelmente ligando-se à molÃculas especÃficas celulares, como por exemplo, selectinas. Para confirmar sua seguranÃa, a PC (8,1 mg/kg) foi administrada em camundongos diariamente e no 7 dia foram coletadas amostras sanguÃneas para dosagens de urÃia e transaminases (TGO e TGP), e pesados rins e fÃgado. Observou-se que a Pc nÃo causou alteraÃÃes significativas, sugerindo portanto, ser segura no perÃodo de administraÃÃo avaliado. Dessa forma, considerando os dados em conjunto, conclui-se que a Pc possui propriedades antinociceptiva e antiinflamatÃria com aÃÃo perifÃrica. / Marine algae lectins had been showing important biotechnical tools. Our objectives were to study the antinociceptive and anti-inflammatory activities of the lectin from the marine red alga Pterocladiella capillacea (Pc). The Pc, presenting haemagglutinating activity against trypsin-treated erytrocytes from rabbit, was purified by application of crude extract (0.025 M Tris-HCl buffer, pH 7.5) on ion exchange chromatography on DEAE-cellulose followed by affinity chromatography on guar-gum column. To proceed, it was used in the nocicepÃÃo and inflammation assays, using male Swiss mice and male Wistar rats, respectively. Pc (0.9; 8.1 or 72.9 mg/kg; i.v) it was administered 30 min before each challenge, that is, before the injection i.p of acetic acid 0.8% (10 &#956;l/mL), of the intraplantar injection of 1% formalin (20 &#956;L/paw) or of the Hot Plate test (52Â1 ÂC), and compared to non treated animals or to pre-treated by Indomethacin or Morphine, both at 5 mg/kg; s.c. It was observed that the Pc (0.9; 8.1 or 72.9 mg/kg) reduced significantly the number of writhes induced by acetic acid (29.2%; 39.3%, and 51.9%, respectively). Pc (72.9 mg/kg) also reduced (p<0.05) the 1st phase (neurogenic) and the 2nd phase (inflammatory) observed after administration of the formalin (58% and 87%, respectively). However, the Pc (72.9 mg/kg) was not capable to reduce the nociception evaluated by Hot Plate test, compared to morphine. These antinociceptive effects were abolished when the Pc was pre-incubated with mucin (1.25 mg/mL), inhibitory glycoprotein of its haemagglutinating activity. Therefore, it is suggested that the antinociceptive activity of the Pc can be predominant by inhibition of peripheric mechanisms. After this, was realized the assays of neutrophil migration for peritoneal cavity or of the paw edema of mice by Carragenan (Cg-type l; 500 g/cavity or paw), where was observed that the administration of the Pc (8,1 mg/kg) 30 min before Cg reduced the neutrophil counts significantly by 84%. However, Pc was not capable to prevent the paw edema induced by Cg. This way, it is suggested that this protein was capable to reduce neutrophil migration by previous mechanism to migration, possibly linking to cellular specific molecules as, for example, selectins. Then, to confirm its safety, the Pc (8.1 mg/kg) was administered daily in mice and observed their behaviors, and at the 7th day, sanguine samples were collected for urea and transaminases (TGO and TGP) dosages, and heavy kidneys and liver. It was observed that Pc did not cause significant alterations, suggesting be safety for the administration period. Considering the data together, it is ended that the Pc possesses antinociceptive and anti-inflammatory properties with peripheral action.

<p>Impulses coming from peripheries are modified in the spinal cord and transmitted to the brain. Several neurotransmitters have been involved in the processing of impulses in the spinal dorsal horn. Acetylcholine (ACh) is one of many neurotransmitters involved in the regulation of nociception in the spinal cord. In this study we investigated the role of nicotinic, muscarinic, serotonergic and GABA receptors in the regulation of spinal ACh release since these receptors are reported to be involved in spinal nociceptive processes.</p><p>Different receptor ligands were infused intraspinally via microdialysis and the spinal ACh release was measured by on-line HPLC. Receptor-ligand binding studies were performed with spinal cord homogenates as well as receptors expressed in cells.</p><p>In the first study, we found that nicotine and some of the nicotinic antagonists used increased ACh release suggesting that spinal ACh release is regulated by different nAChRs. Nicotine and nicotinic agonists may act on different types of receptors with different affinity to produce the observed net effect of increased ACh release. We propose the possibility of an involvement of three different nicotinic receptor subtypes in the regulation of spinal ACh release. </p><p>The effect of epibatidine, which is regarded as a nicotinic agonist, on muscarinic receptors was investigated in the second study. We propose that epibatidine, in μM concentrations, is a partial muscarinic receptor agonist that may interact with spinal muscarinic receptors to increase ACh release. The dual action on both nAChRs and mAChRs may explain the potent analgesic effect observed after intra-spinal epibatidine administration.</p><p>In the third study, we investigated the role of serotonin receptor involvement in ACh release control. The results suggest that only 5-HT_1A and 5-HT_2A receptors are involved in spinal ACh release. Considering current knowledge, the most probable location of 5-HT_2A receptors is on cholinergic neurones. On activation of the 5-HT_2A receptors the cellular excitability of cholinergic neurones is increased which results in an increasing ACh release. The 5-HT_1A receptors might be located on cell bodies of GABA neurones which inhibit the firing rate of the GABA neurones when activated by serotonin. </p><p>In the fourth study, we investigated the GABA receptor involvement in the regulation in spinal ACh release. We found that GABA_A receptors are tonically inhibiting spinal ACh release. The results further suggest that GABA_B receptors also are involved in the regulation of spinal ACh release. However, unlike GABA_A antagonists, GABA_B antagonists do not increase ACh release. This suggests that GABA_B receptors are not tonically regulating the spinal ACh release. </p>