La lodopyridone est un alcaloïde isolé par William Fenical en 2009 à partir de l’actinomycète marin Saccharomonospora sp. CNQ490 présent dans les sédiments du cayon sous-marin de La Jolla aux États-Unis. Cette structure polyhétérocyclique, plutôt surprenante de prime abord pour une substance naturelle, est en fait un tétrapeptide modifié. Pour réaliser la synthèse totale de la molécule et nous démarquer des synthèses antérieures, nous avons imaginé une approche basée sur la construction de la pyridone centrale en faisant intervenir une réaction d’électrocyclisation originale et d’inspiration biomimétique. Les fragments nécessaires pour la réalisation de l’étape clé ont été préparés par des méthodes courtes et originales développées au laboratoire. Intrigués par l’histoire récente du « tramadol naturel », nous nous sommes aussi penchés sur les hypothèses de biosynthèse proposées en essayant, au laboratoire, de mimer les cascades de condensation des précurseurs proposés. En parallèle, une étude phytochimique du lycopode Lycopodiella cernua et de la plante Nitraria retusa a été réalisée. / Lodopyridone is an alkaloid isolated by William Fenical in 2009 from the marine actinomycete Saccharomonospora sp. CNQ490 found in the sediments of the submarine cayon of La Jolla (United States). This polyheterocyclic structure, rather surprising at first for a natural substance, is actually a modified tetrapeptide. To achieve the total synthesis of the molecule and differentiate us from the previous syntheses, we imagined an approach based on the construction of the central pyridone ring by an original pericyclic reaction inspired from the biosynthetic route. The two fragments necessary for the key step were prepared by short and original methods developed in our laboratory. Intrigued by the recent “natural tramadol” story, we also envisaged its synthesis exploiting the proposed biosynthetic pathway. In parallel a phytochemical study of the moss Lycopodiella cernua and the plant Nitraria retusa were performed.

Master of Science / Department of Clinical Sciences / James K. Roush / Hydrocodone and tramadol are opioid analgesics. No studies have been performed to evaluate the clinical efficacy or pharmacokinetics of hydrocodone/acetaminophen and tramadol in a heterogenous population of dogs. The efficacy of tramadol in dogs has been questioned based on previous pharmacokinetic data. The objectives of this study were to evaluate the analgesic effects of hydrocodone/acetaminophen and tramadol measured by a success/failure model and to determine the pharmacokinetic profile of each drug following the second oral drug dose administration. Fifty client-owned dogs presenting for routine tibial plateau leveling osteotomy were randomized to receive either oral hydrocodone/acetaminophen or tramadol in the postoperative period. A blinded investigator using a modified Glasgow Composite Measure Pain Scale scored each animal. Treatment failures were recorded and compared statistically for differences between the two groups. Blood sampling for pharmacokinetic analysis was initiated after the second oral dose. Mean [plus or minus] SE dose of hydrocodone/acetaminophen administered was 0.5 [plus or minus] 0.04 mg/kg and 16.6 [plus or minus] 1.41 mg/kg for hydrocodone and acetaminophen, respectively. Mean [plus or minus] SE dose of tramadol administered was 5.91[plus or minus] 0.61 mg/kg. The terminal half life, maximal serum concentration (Cmax) and time to maximal serum concentration (Tmax) for tramadol were approximately 1.56 hours, 155.6 ng/mL and 3.90 hours, respectively. Plasma concentrations of the active metabolite O-desmethyltramadol (M1) were low. For hydrocodone, the Cmax and Tmax were approximately 7.90 ng/mL and 3.47 hours, respectively. Plasma concentrations of hydromorphone were low after oral hydrocodone administration. Eighteen of 48 (37.5%) dogs required additional rescue analgesic therapy. This included 10 dogs in hydrocodone group and 8 dogs in the tramadol group (p=0.628). In a group of postoperative patients, no difference in pain scoring could be detected in hydrocodone/acetaminophen and tramadol groups. The pharmacokinetics of tramadol and metabolites were similar to previous studies. Wide variations existed in tramadol drug concentrations and the effects of tramadol are likely independent of the μ-opioid receptor. There is poor metabolism of hydrocodone to hydromorphone in dogs, however, efficacy may be achieved through hydrocodone. The analgesic efficacy of tramadol, 5-7 mg/kg PO q 8 h, and hydrocodone, 0.5 mg/kg PO q 8 h, should be assessed further prior to widespread use in canine postoperative patients.

Objectives To compare the anaesthetic, analgesic and cardiorespiratory effects of intramuscular medetomidine and ketamine administered alone or combined with morphine or tramadol for orchiectomy in cats. Study design Randomised, blinded, prospective clinical study. Animals Thirty client owned healthy cats. Materials and methods Cats received a combination of medetomidine (60 μg kg-1) and ketamine (10 mg kg-1) alone (MedK) or combined with morphine (0.2 mg kg-1) (MedKM) or tramadol (2 mg kg-1) (MedKT) intramuscularly. Time of different events and physiological parameters were recorded by a blinded researcher. Pre-surgery arterial and venous blood gases were measured. Heart rate (HR), respiration rate (fR), systolic arterial blood pressure (SABP), peripheral haemoglobin saturation (SpO2) and end-tidal carbon dioxide tension (PETCO2) were recorded every 5 minutes of general anaesthesia and at each surgical stage. Post-operative analgesia was evaluated with a visual analogue scale, a multidimensional composite scoring system and a rigid tip von Frey mechanical threshold device every hour from 3 to 8 hours post-injection of the initial combination of drugs. Data were analysed with a linear mixed model, Kruskal Wallis or Chi-square tests (p < 0.05). Results Median (range) induction and recovery times (minutes) were not significantly (P = 0.125) different among the three combinations: 5.6 (2.7, 8.0), 7.4 (5.1, 9.6) and 8 (5.8, 14.9) for induction and 128 (95, 143), 166 (123, 210) and 143 (123, 180) for recovery, with MedK, MedKT and MedKM, respectively. All three combinations caused similar low partial pressure of arterial oxygen (PaO2) values (mean ± SD: 66.2 ± 1.7 mmHg). Surgery had a significant effect on SABP (p < 0.001), SpO2 (p < 0.001), fR (p = 0.003) and HR (p = 0.002), which increased; and PETCO2 (p = 0.003), which decreased, with all combinations. Non-significant differences were found in pain scores and von Frey results among treatments; however, the von Frey changes over time did vary by treatment (p < 0.001) with the MedK group returning to baseline values more rapidly than MedKM and MedKT. None of the cats required rescue analgesics. Conclusion and clinical relevance All three protocols provide adequate anaesthesia and analgesia for orchiectomy in cats. However, rescue intervention to maintain surgical anaesthesia such as isoflurane may be required in some cats. Oxygen should be supplemented. / Dissertation (MMedVet)--University of Pretoria, 2013 / gm2014 / Companion Animal Clinical Studies / unrestricted

Foi estudado o efeito analgésico e anestésico adjuvante do cloridrato de tramadol aplicado localmente, após extração do terceiro molar inferior impactado. Um total de 52 pacientes foi submetido à exodontia sob anestesia local (mepivacaína 2% 1:20 000 corbadrina), em estudo duplo-cego, dose única, cruzado, controlado por placebo. Pacientes e os lados dos procedimentos foram distribuídos aleatoriamente para receberem 2 ml de tramadol (100%) (grupo T) ou 2 ml de solução salina 0,9% (grupo P). Ambas as soluções foram injetadas na submucosa gengival e alvéolo, imediatamente após as cirurgias realizadas por um mesmo cirurgião. Impacção dental e quantidade anestésica foram pareadas. Dados do consumo e a hora de uso de analgésico de resgate (dipirona 500 mg) foram utilizados para avaliar o efeito analgésico de tramadol. Uma Escala Analógica Visual (EAV) de dor foi aplicada após término da anestesia, 4, 8, 24, 48 e 72 horas após cirurgia, com os dados submetidos ao teste de Wilcoxon (p < 0,05). Não houve diferença no bloqueio anestésico e efeitos adversos entre os grupos. O grupo T requisitou um número significativamente menor (p = 0,008) de comprimidos de dipirona durante o período de avaliação (3,37 ± 4,65) do que o grupo P (4,4 ± 3,71). O grupo T levou mais minutos para usar a dipirona após a primeira cirurgia (303,72 ± 416,01) do que o grupo P (185,4 ± 59,4) (p = 0,006). O grupo T apresentou menor média de dor na EAV após término da anestesia (3,55 ± 2,27) do que no grupo P (5,26 ± 2,49) (p = 0,001). O tramadol administrado localmente após exodontia de terceiros molares inferiores melhora a qualidade da analgesia pós-operatória, porém não prolonga a duração da anestesia local com mepivacaína. / The present study sought to assess the analgesic and adjuvant anesthetic effects of surgical site administration of tramadol hydrochloride immediately after extraction of impacted mandibular third molars. In this double-blind, placebo-controlled, singledose, crossover investigation, 52 patients underwent bilateral extraction of impacted mandibular third molars under local anesthesia (mepivacaine 2% with levonordefrin 1:20 000). Patients and procedures, by side of intervention, were randomly assigned to receive either 2 mL of tramadol (100%) (Group T, n = 52) or 2 mL of normal saline, 0.9% (Group P, n = 52). Medications were administered by submucosal injection at the level of the third molar immediately after surgery. All patients were operated on by the same surgeon; patients were paired for technical difficulty and amount of anesthetic solution. Use of supplementary analgesics (500 mg metamizole) and time to first postoperative use of a rescue drug were used to assess the analgesic effect of tramadol. Pain level on both sides (Group T and P) was recorded on a visual analog scale (VAS 010 cm) immediately after cessation of anesthetic effect and at 4, 8, 24, 48, and 72 hours postoperatively. Data were compared using the Wilcoxon test (p < 0.05). There was no difference in anesthetic blockade between groups. There were no differences in reported adverse effects. In the 72 hours following surgery, patients in group T took significantly fewer (p = 0.008) metamizole tablets (3.37 ± 4.65) than did those in group P (4.4 ± 3.71). Time to first dose of a rescue drug (in minutes) was longer in Group T (303.72 ± 416.01) than in Group P (185.4 ± 59.4) (p = 0.006). Tramadol reduced pain intensity values (VAS) significantly in Group T (3.55 ± 2.27) as compared to Group P (5.26 ± 2.49) after anesthetic effect had worn off (p = 0.001). Local administration of tramadol after oral surgery improves the quality of postoperative analgesia, but does not extend the duration of anesthetic action.

O cloridrato de tramadol é um analgésico de ação central, análogo sintético da codeína e morfina, o qual vem sendo amplamente estudado em equinos, sendo avaliado sua farmacocinética e farmacodinâmica. Em humanos, há relato de que o tramadol é substrato para a Gp-P, o que pode ser fator limitante na absorção do tramadol. A Gp-P funciona como uma bomba de efluxo celular, de maneira que, transporta ativamente xenobióticos do meio intracelular para o extracelular, atuando como um mecanismo de proteção contra xenobióticos. O estudo teve como objetivo a detecção do Gene MDR1 a partir do cDNA, e avaliar as alterações fisiológicas e efeito analgésico do tramadol em equinos submetidos a inibição da Gp-P entérica pela ivermectina. Seis equinos, machos e fêmeas, pesando 448±68Kg, foram distribuídos em três grupos autocontrole, recebendo tramadol por sonda nasogástrica na dose 1 mg/kg (GT1), 4 mg/kg (GT4) e recebendo tramadol 1mg/kg associada a ivermectina 0,2mg/kg VO. Foram avaliados FC, f, motilidade intestinal, temperatura corpórea aos 30 min antes, imediatamente antes da administração de qualquer substância para determinação dos valores basais e aos 30min, 60 min, 90 min, 120 min e a cada 60 min até 360 min após o tratamento. A claudicação foi avaliada aos 30 min, 60 min e a cada 60 min até os 360 min. Os parâmetros hemogasométricos foram avaliados no momento 0, 60 min e 120 min. Para as variáveis paramétricas utilizou-se análise de variância (ANOVA) para amostras pareadas, com posterior teste de Dunnett. Para comparações entre os grupos, realizou-se análise de variância, seguido de teste de Tukey. Para a variável não-paramétrica, motilidade intestinal, utilizou-se teste de Wilcoxon para amostras pareadas. As diferenças foram consideradas significantes quando P<0,05. Não foram observadas diferenças na FC e na avaliação analgésica. Houve hipomotilidade no GT1 e GT4 apenas ao final das avaliações e aumento da f em todos os grupos. Houve aumento do HCO3+ e redução do K+ e Ca++. Conclui-se que a inibição da Gp-P entérica pela ivermectina não alterou os efeitos do tramadol nas doses estudadas, sugerindo que o mesmo não é substrato para Gp-P, mas estudos futuros devem ser realizados a fim de avaliar a interação da ivermectina como inibidor da Gp-P na farmacocinética do tramadol. / Tramadol hydrochloride is a centrally acting analgesic, synthetic analogue of codeine and morphine, which has been widely studied in horses, being evaluated its pharmacokinetics and pharmacodynamics. In humans, there is a report that tramadol is a substrate for P-gp, which can be a limiting factor in the absorption of tramadol. P-gp acts as an efflux pump cell, that actively transports xenobiotics from the intracellular to the extracellular environment, acting as a protective mechanism against xenobiotic. The study aimed the detection of MDR1 Gene from cDNA, and the evaluation of physiological parameters and analgesic effect of tramadol in horses submitted to inhibition of enteric P-gp by ivermectin. Six horses, control of themselves, male and female, weighing 448 ± 68kg, were distributed into three groups, receiving tramadol by nasogastric tube in dose of 1 mg/kg (GT1), 4 mg/kg (GT4) and tramadol 1 mg/kg associated with ivermectin 0.2 mg/kg orally. Were evaluated HR, RR, intestinal motility, body temperature 30 min before, and immediately before the administration of any substance for determination of baseline and posterior at 30 min, 60 min, 90 min, 120 min and every 60 min up to 360 min after treatment. The analgesic evaluation occurred at 30 min, 60 min and every 60 min to 360 min. Blood gas parameters were evaluated at 0, 60 min and 120 min. For parametric variables were used analysis of variance (ANOVA) for paired samples, followed by Dunnett's test. For comparisons between groups, ANOVA followed by Tukey test were used. The non-parametric variable, intestinal motility, we used the Wilcoxon test for paired samples. Differences were considered significant when P <0.05. Differences in HR and analgesic evaluation were not observed. Hypomotility occurs in GT1 and GT4 only at the end of evaluation and RR increased in all groups. There was an increase of HCO3- and reduction of K+ and Ca++. We conclude that inhibition of enteric P-gp by ivermectin did not alter the effects of tramadol in the studied doses, suggesting that tramadol it is not a substrate for P-gp, but future studies should be conducted to assess the interaction of ivermectin as inhibitor of P-gp on the pharmacokinetics of tramadol.

O cloridrato de tramadol é um analgésico de ação central, análogo sintético da codeína e morfina, o qual vem sendo amplamente estudado em equinos, sendo avaliado sua farmacocinética e farmacodinâmica. Em humanos, há relato de que o tramadol é substrato para a Gp-P, o que pode ser fator limitante na absorção do tramadol. A Gp-P funciona como uma bomba de efluxo celular, de maneira que, transporta ativamente xenobióticos do meio intracelular para o extracelular, atuando como um mecanismo de proteção contra xenobióticos. O estudo teve como objetivo a detecção do Gene MDR1 a partir do cDNA, e avaliar as alterações fisiológicas e efeito analgésico do tramadol em equinos submetidos a inibição da Gp-P entérica pela ivermectina. Seis equinos, machos e fêmeas, pesando 448±68Kg, foram distribuídos em três grupos autocontrole, recebendo tramadol por sonda nasogástrica na dose 1 mg/kg (GT1), 4 mg/kg (GT4) e recebendo tramadol 1mg/kg associada a ivermectina 0,2mg/kg VO. Foram avaliados FC, f, motilidade intestinal, temperatura corpórea aos 30 min antes, imediatamente antes da administração de qualquer substância para determinação dos valores basais e aos 30min, 60 min, 90 min, 120 min e a cada 60 min até 360 min após o tratamento. A claudicação foi avaliada aos 30 min, 60 min e a cada 60 min até os 360 min. Os parâmetros hemogasométricos foram avaliados no momento 0, 60 min e 120 min. Para as variáveis paramétricas utilizou-se análise de variância (ANOVA) para amostras pareadas, com posterior teste de Dunnett. Para comparações entre os grupos, realizou-se análise de variância, seguido de teste de Tukey. Para a variável não-paramétrica, motilidade intestinal, utilizou-se teste de Wilcoxon para amostras pareadas. As diferenças foram consideradas significantes quando P<0,05. Não foram observadas diferenças na FC e na avaliação analgésica. Houve hipomotilidade no GT1 e GT4 apenas ao final das avaliações e aumento da f em todos os grupos. Houve aumento do HCO3+ e redução do K+ e Ca++. Conclui-se que a inibição da Gp-P entérica pela ivermectina não alterou os efeitos do tramadol nas doses estudadas, sugerindo que o mesmo não é substrato para Gp-P, mas estudos futuros devem ser realizados a fim de avaliar a interação da ivermectina como inibidor da Gp-P na farmacocinética do tramadol. / Tramadol hydrochloride is a centrally acting analgesic, synthetic analogue of codeine and morphine, which has been widely studied in horses, being evaluated its pharmacokinetics and pharmacodynamics. In humans, there is a report that tramadol is a substrate for P-gp, which can be a limiting factor in the absorption of tramadol. P-gp acts as an efflux pump cell, that actively transports xenobiotics from the intracellular to the extracellular environment, acting as a protective mechanism against xenobiotic. The study aimed the detection of MDR1 Gene from cDNA, and the evaluation of physiological parameters and analgesic effect of tramadol in horses submitted to inhibition of enteric P-gp by ivermectin. Six horses, control of themselves, male and female, weighing 448 ± 68kg, were distributed into three groups, receiving tramadol by nasogastric tube in dose of 1 mg/kg (GT1), 4 mg/kg (GT4) and tramadol 1 mg/kg associated with ivermectin 0.2 mg/kg orally. Were evaluated HR, RR, intestinal motility, body temperature 30 min before, and immediately before the administration of any substance for determination of baseline and posterior at 30 min, 60 min, 90 min, 120 min and every 60 min up to 360 min after treatment. The analgesic evaluation occurred at 30 min, 60 min and every 60 min to 360 min. Blood gas parameters were evaluated at 0, 60 min and 120 min. For parametric variables were used analysis of variance (ANOVA) for paired samples, followed by Dunnett's test. For comparisons between groups, ANOVA followed by Tukey test were used. The non-parametric variable, intestinal motility, we used the Wilcoxon test for paired samples. Differences were considered significant when P <0.05. Differences in HR and analgesic evaluation were not observed. Hypomotility occurs in GT1 and GT4 only at the end of evaluation and RR increased in all groups. There was an increase of HCO3- and reduction of K+ and Ca++. We conclude that inhibition of enteric P-gp by ivermectin did not alter the effects of tramadol in the studied doses, suggesting that tramadol it is not a substrate for P-gp, but future studies should be conducted to assess the interaction of ivermectin as inhibitor of P-gp on the pharmacokinetics of tramadol.

Foi estudado o efeito analgésico e anestésico adjuvante do cloridrato de tramadol aplicado localmente, após extração do terceiro molar inferior impactado. Um total de 52 pacientes foi submetido à exodontia sob anestesia local (mepivacaína 2% 1:20 000 corbadrina), em estudo duplo-cego, dose única, cruzado, controlado por placebo. Pacientes e os lados dos procedimentos foram distribuídos aleatoriamente para receberem 2 ml de tramadol (100%) (grupo T) ou 2 ml de solução salina 0,9% (grupo P). Ambas as soluções foram injetadas na submucosa gengival e alvéolo, imediatamente após as cirurgias realizadas por um mesmo cirurgião. Impacção dental e quantidade anestésica foram pareadas. Dados do consumo e a hora de uso de analgésico de resgate (dipirona 500 mg) foram utilizados para avaliar o efeito analgésico de tramadol. Uma Escala Analógica Visual (EAV) de dor foi aplicada após término da anestesia, 4, 8, 24, 48 e 72 horas após cirurgia, com os dados submetidos ao teste de Wilcoxon (p < 0,05). Não houve diferença no bloqueio anestésico e efeitos adversos entre os grupos. O grupo T requisitou um número significativamente menor (p = 0,008) de comprimidos de dipirona durante o período de avaliação (3,37 ± 4,65) do que o grupo P (4,4 ± 3,71). O grupo T levou mais minutos para usar a dipirona após a primeira cirurgia (303,72 ± 416,01) do que o grupo P (185,4 ± 59,4) (p = 0,006). O grupo T apresentou menor média de dor na EAV após término da anestesia (3,55 ± 2,27) do que no grupo P (5,26 ± 2,49) (p = 0,001). O tramadol administrado localmente após exodontia de terceiros molares inferiores melhora a qualidade da analgesia pós-operatória, porém não prolonga a duração da anestesia local com mepivacaína. / The present study sought to assess the analgesic and adjuvant anesthetic effects of surgical site administration of tramadol hydrochloride immediately after extraction of impacted mandibular third molars. In this double-blind, placebo-controlled, singledose, crossover investigation, 52 patients underwent bilateral extraction of impacted mandibular third molars under local anesthesia (mepivacaine 2% with levonordefrin 1:20 000). Patients and procedures, by side of intervention, were randomly assigned to receive either 2 mL of tramadol (100%) (Group T, n = 52) or 2 mL of normal saline, 0.9% (Group P, n = 52). Medications were administered by submucosal injection at the level of the third molar immediately after surgery. All patients were operated on by the same surgeon; patients were paired for technical difficulty and amount of anesthetic solution. Use of supplementary analgesics (500 mg metamizole) and time to first postoperative use of a rescue drug were used to assess the analgesic effect of tramadol. Pain level on both sides (Group T and P) was recorded on a visual analog scale (VAS 010 cm) immediately after cessation of anesthetic effect and at 4, 8, 24, 48, and 72 hours postoperatively. Data were compared using the Wilcoxon test (p < 0.05). There was no difference in anesthetic blockade between groups. There were no differences in reported adverse effects. In the 72 hours following surgery, patients in group T took significantly fewer (p = 0.008) metamizole tablets (3.37 ± 4.65) than did those in group P (4.4 ± 3.71). Time to first dose of a rescue drug (in minutes) was longer in Group T (303.72 ± 416.01) than in Group P (185.4 ± 59.4) (p = 0.006). Tramadol reduced pain intensity values (VAS) significantly in Group T (3.55 ± 2.27) as compared to Group P (5.26 ± 2.49) after anesthetic effect had worn off (p = 0.001). Local administration of tramadol after oral surgery improves the quality of postoperative analgesia, but does not extend the duration of anesthetic action.

O cloridrato de tramadol é um analgésico de ação central, análogo sintético da codeína e morfina, o qual vem sendo amplamente estudado em equinos, sendo avaliado sua farmacocinética e farmacodinâmica. Em humanos, há relato de que o tramadol é substrato para a Gp-P, o que pode ser fator limitante na absorção do tramadol. A Gp-P funciona como uma bomba de efluxo celular, de maneira que, transporta ativamente xenobióticos do meio intracelular para o extracelular, atuando como um mecanismo de proteção contra xenobióticos. O estudo teve como objetivo a detecção do Gene MDR1 a partir do cDNA, e avaliar as alterações fisiológicas e efeito analgésico do tramadol em equinos submetidos a inibição da Gp-P entérica pela ivermectina. Seis equinos, machos e fêmeas, pesando 448±68Kg, foram distribuídos em três grupos autocontrole, recebendo tramadol por sonda nasogástrica na dose 1 mg/kg (GT1), 4 mg/kg (GT4) e recebendo tramadol 1mg/kg associada a ivermectina 0,2mg/kg VO. Foram avaliados FC, f, motilidade intestinal, temperatura corpórea aos 30 min antes, imediatamente antes da administração de qualquer substância para determinação dos valores basais e aos 30min, 60 min, 90 min, 120 min e a cada 60 min até 360 min após o tratamento. A claudicação foi avaliada aos 30 min, 60 min e a cada 60 min até os 360 min. Os parâmetros hemogasométricos foram avaliados no momento 0, 60 min e 120 min. Para as variáveis paramétricas utilizou-se análise de variância (ANOVA) para amostras pareadas, com posterior teste de Dunnett. Para comparações entre os grupos, realizou-se análise de variância, seguido de teste de Tukey. Para a variável não-paramétrica, motilidade intestinal, utilizou-se teste de Wilcoxon para amostras pareadas. As diferenças foram consideradas significantes quando P<0,05. Não foram observadas diferenças na FC e na avaliação analgésica. Houve hipomotilidade no GT1 e GT4 apenas ao final das avaliações e aumento da f em todos os grupos. Houve aumento do HCO3+ e redução do K+ e Ca++. Conclui-se que a inibição da Gp-P entérica pela ivermectina não alterou os efeitos do tramadol nas doses estudadas, sugerindo que o mesmo não é substrato para Gp-P, mas estudos futuros devem ser realizados a fim de avaliar a interação da ivermectina como inibidor da Gp-P na farmacocinética do tramadol. / Tramadol hydrochloride is a centrally acting analgesic, synthetic analogue of codeine and morphine, which has been widely studied in horses, being evaluated its pharmacokinetics and pharmacodynamics. In humans, there is a report that tramadol is a substrate for P-gp, which can be a limiting factor in the absorption of tramadol. P-gp acts as an efflux pump cell, that actively transports xenobiotics from the intracellular to the extracellular environment, acting as a protective mechanism against xenobiotic. The study aimed the detection of MDR1 Gene from cDNA, and the evaluation of physiological parameters and analgesic effect of tramadol in horses submitted to inhibition of enteric P-gp by ivermectin. Six horses, control of themselves, male and female, weighing 448 ± 68kg, were distributed into three groups, receiving tramadol by nasogastric tube in dose of 1 mg/kg (GT1), 4 mg/kg (GT4) and tramadol 1 mg/kg associated with ivermectin 0.2 mg/kg orally. Were evaluated HR, RR, intestinal motility, body temperature 30 min before, and immediately before the administration of any substance for determination of baseline and posterior at 30 min, 60 min, 90 min, 120 min and every 60 min up to 360 min after treatment. The analgesic evaluation occurred at 30 min, 60 min and every 60 min to 360 min. Blood gas parameters were evaluated at 0, 60 min and 120 min. For parametric variables were used analysis of variance (ANOVA) for paired samples, followed by Dunnett's test. For comparisons between groups, ANOVA followed by Tukey test were used. The non-parametric variable, intestinal motility, we used the Wilcoxon test for paired samples. Differences were considered significant when P <0.05. Differences in HR and analgesic evaluation were not observed. Hypomotility occurs in GT1 and GT4 only at the end of evaluation and RR increased in all groups. There was an increase of HCO3- and reduction of K+ and Ca++. We conclude that inhibition of enteric P-gp by ivermectin did not alter the effects of tramadol in the studied doses, suggesting that tramadol it is not a substrate for P-gp, but future studies should be conducted to assess the interaction of ivermectin as inhibitor of P-gp on the pharmacokinetics of tramadol.

INTRODUÇÃO: Tramadol é conhecido como um fármaco analgésico de ação central utilizado no tratamento de dores de intensidades moderada a forte. Efeito analgésico local já foi demonstrado. É, em parte, semelhante ao efeito anestésico local, mas outros mecanismos permanecem desconhecidos. O papel de receptores opioides periféricos na analgesia do tramadol na dor pós-operatória não é conhecido. Neste estudo, foi estudado o papel dos receptores opioides no efeito analgésico local do tramadol em modelo de dor por incisão plantar. MÉTODOS: Ratos machos jovens foram submetidos à incisão plantar e no primeiro dia pós-incisão foram divididos em quatro grupos: Grupo IP I-SF/SF - 50 uL de solução de NaCl 0,9% foram injetados na região plantar da pata posterior homolateral à incisão e, 15 minutos depois, novamente injetada a mesma quantidade de solução; Grupo IP II-SF/T_homo - 50 uL de NaCl 0,9% foram injetados na região plantar da pata homolateral e, 15 minutos depois, injetados 50 µL solução contendo 5 mg tramadol; Grupo IP III-SF/T_contra -50 uL de NaCl 0,9% foram injetados na região plantar da pata contralateral e, 15 minutos depois, 50 uL de solução contendo 5 mg de tramadol; Grupo IP IV-Nal/T_homo - 50 uL de solução contendo 200 ug de naloxona foram injetados na pata homolateral e, 15 minutos depois, 50 uL de solução contendo 5mg de tramadol foi injetada. Antes de receberem as injeções, os limiares de retirada da pata por estímulo mecânico produzido por analgesímetro eletrônico de von Frey foram medidos, e, depois da administração dos fármacos, os limiares de retirada foram avaliados nos tempos 15, 30, 45 e 60 minutos após a administração dos fármacos. O mesmo procedimento foi utilizado no segundo dia pós-incisão. As expressões proteicas dos receptores opioide ? (DOR) e µ (MOR) foram avaliadas usando técnica de immunoblotting de gânglios de raízes dorsais homolaterais (L3, L4, L5 e L6) de grupos de animais sem incisão e após 1, 2, 3 e 7 dias de animais submetidos à incisão plantar. RESULTADOS: A incisão plantar gerou marcada hiperalgesia mecânica que foi revertida por tramadol intraplantar nos dois dias. O tramadol intraplantar em pata contralateral não antagonizou a hiperalgesia mecânica, a naloxona antagonizou parcialmente o efeito analgésico do tramadol no primeiro dia pós-incisão, e antagonizou completamente no segundo dia pós-incisão. A expressão proteica de DOR aumentou no 2º, 3º e 7º dias pós-incisão, a expressão de MOR não se modificou. CONCLUSÕES: O tramadol apresentou efeito analgésico local após estímulo mecânico e esse efeito foi antagonizado por naloxona no segundo dia pós-incisão. A expressão de DOR aumentou após a incisão plantar / BACKGROUND: Tramadol is known as a central acting analgesic drugused for the treatment of moderate to severe pain. Local analgesic effect was already demonstrated. It is in part due to local anesthetic-like effect, but other mechanisms remain unclear. The role of peripheral opioid receptors in the local analgesic effect in postoperative pain is not known. In this study, we examined the role of peripheral opioid receptors in the local analgesic effect of tramadol in the plantar incision pain model. METHODS: Young male Wistar rats were submitted to plantar incision and in the first postoperative day (POD1) were divided into four groups:IP I-SF/SF,50 uL of 0.9% NaCl solution were injected in the plantar aspect of the homolateral hindpaw and again after 15 minutes; IP II-SF/T_homo, 50 uL of 0.9% NaCl solution were injected in the plantar aspect of the homolateral hindpaw and, 15 minutes later, 50 µL of solution containing 5 mg tramadol were injected in the same hindpaw; IP III-SF/T_contra, 50 uL of 0.9% NaCl were injected in the plantar aspect of the contralateral hindpaw and, 15 minutes later, 50 uL of solution containing 5 mg tramadol were injected in the same hindpaw; IP IVNal/T_homo, 50 uL of naloxone (200 ug) solution were injected in the homolateral hindpaw and 15 minutes later 50 µL of solution containing 5 mg tramadol were injected. Before receiving the assigned drugs, baseline withdrawal thresholds for mechanical hyperalgesia using electronic von Frey were measured, then, after receiving the assigned drugs, withdrawal thresholds were measured at 15, 30, 45 and 60 min after drug injection. The same procedure was repeated in POD2. u opioid receptor (MOR) and opioid receptor (DOR) protein expressions were evaluated using immunoblotting after removal of ipsilateral dorsal root ganglia (L3, L4, L5 and L6) in groups of rats non submitted to plantar incision and 1, 2, 3 and 7 days after incision. RESULTS: Plantar incision led to marked mechanical hyperalgesia that was reversed with intraplantar tramadol in both days. Contralateral tramadol did not affect mechanical hyperalgesia and naloxone antagonized partially intraplantar tramadol in POD1, and antagonized completely in POD2. DOR expression in DRGs increased in POD2, POD3 and POD7, MOR expression did not change. CONCLUSIONS: Tramadol presented local analgesic effect after mechanical stimuli and this effect was antagonized by naloxone in the second post incision day. DOR increased expression after plantar incision

INTRODUÇÃO: Tramadol é conhecido como um fármaco analgésico de ação central utilizado no tratamento de dores de intensidades moderada a forte. Efeito analgésico local já foi demonstrado. É, em parte, semelhante ao efeito anestésico local, mas outros mecanismos permanecem desconhecidos. O papel de receptores opioides periféricos na analgesia do tramadol na dor pós-operatória não é conhecido. Neste estudo, foi estudado o papel dos receptores opioides no efeito analgésico local do tramadol em modelo de dor por incisão plantar. MÉTODOS: Ratos machos jovens foram submetidos à incisão plantar e no primeiro dia pós-incisão foram divididos em quatro grupos: Grupo IP I-SF/SF - 50 uL de solução de NaCl 0,9% foram injetados na região plantar da pata posterior homolateral à incisão e, 15 minutos depois, novamente injetada a mesma quantidade de solução; Grupo IP II-SF/T_homo - 50 uL de NaCl 0,9% foram injetados na região plantar da pata homolateral e, 15 minutos depois, injetados 50 µL solução contendo 5 mg tramadol; Grupo IP III-SF/T_contra -50 uL de NaCl 0,9% foram injetados na região plantar da pata contralateral e, 15 minutos depois, 50 uL de solução contendo 5 mg de tramadol; Grupo IP IV-Nal/T_homo - 50 uL de solução contendo 200 ug de naloxona foram injetados na pata homolateral e, 15 minutos depois, 50 uL de solução contendo 5mg de tramadol foi injetada. Antes de receberem as injeções, os limiares de retirada da pata por estímulo mecânico produzido por analgesímetro eletrônico de von Frey foram medidos, e, depois da administração dos fármacos, os limiares de retirada foram avaliados nos tempos 15, 30, 45 e 60 minutos após a administração dos fármacos. O mesmo procedimento foi utilizado no segundo dia pós-incisão. As expressões proteicas dos receptores opioide ? (DOR) e µ (MOR) foram avaliadas usando técnica de immunoblotting de gânglios de raízes dorsais homolaterais (L3, L4, L5 e L6) de grupos de animais sem incisão e após 1, 2, 3 e 7 dias de animais submetidos à incisão plantar. RESULTADOS: A incisão plantar gerou marcada hiperalgesia mecânica que foi revertida por tramadol intraplantar nos dois dias. O tramadol intraplantar em pata contralateral não antagonizou a hiperalgesia mecânica, a naloxona antagonizou parcialmente o efeito analgésico do tramadol no primeiro dia pós-incisão, e antagonizou completamente no segundo dia pós-incisão. A expressão proteica de DOR aumentou no 2º, 3º e 7º dias pós-incisão, a expressão de MOR não se modificou. CONCLUSÕES: O tramadol apresentou efeito analgésico local após estímulo mecânico e esse efeito foi antagonizado por naloxona no segundo dia pós-incisão. A expressão de DOR aumentou após a incisão plantar / BACKGROUND: Tramadol is known as a central acting analgesic drugused for the treatment of moderate to severe pain. Local analgesic effect was already demonstrated. It is in part due to local anesthetic-like effect, but other mechanisms remain unclear. The role of peripheral opioid receptors in the local analgesic effect in postoperative pain is not known. In this study, we examined the role of peripheral opioid receptors in the local analgesic effect of tramadol in the plantar incision pain model. METHODS: Young male Wistar rats were submitted to plantar incision and in the first postoperative day (POD1) were divided into four groups:IP I-SF/SF,50 uL of 0.9% NaCl solution were injected in the plantar aspect of the homolateral hindpaw and again after 15 minutes; IP II-SF/T_homo, 50 uL of 0.9% NaCl solution were injected in the plantar aspect of the homolateral hindpaw and, 15 minutes later, 50 µL of solution containing 5 mg tramadol were injected in the same hindpaw; IP III-SF/T_contra, 50 uL of 0.9% NaCl were injected in the plantar aspect of the contralateral hindpaw and, 15 minutes later, 50 uL of solution containing 5 mg tramadol were injected in the same hindpaw; IP IVNal/T_homo, 50 uL of naloxone (200 ug) solution were injected in the homolateral hindpaw and 15 minutes later 50 µL of solution containing 5 mg tramadol were injected. Before receiving the assigned drugs, baseline withdrawal thresholds for mechanical hyperalgesia using electronic von Frey were measured, then, after receiving the assigned drugs, withdrawal thresholds were measured at 15, 30, 45 and 60 min after drug injection. The same procedure was repeated in POD2. u opioid receptor (MOR) and opioid receptor (DOR) protein expressions were evaluated using immunoblotting after removal of ipsilateral dorsal root ganglia (L3, L4, L5 and L6) in groups of rats non submitted to plantar incision and 1, 2, 3 and 7 days after incision. RESULTS: Plantar incision led to marked mechanical hyperalgesia that was reversed with intraplantar tramadol in both days. Contralateral tramadol did not affect mechanical hyperalgesia and naloxone antagonized partially intraplantar tramadol in POD1, and antagonized completely in POD2. DOR expression in DRGs increased in POD2, POD3 and POD7, MOR expression did not change. CONCLUSIONS: Tramadol presented local analgesic effect after mechanical stimuli and this effect was antagonized by naloxone in the second post incision day. DOR increased expression after plantar incision