Localization of opioid receptors in the central nervous system and assessment of morphine and butorphanol analgesic and sedative effects in green iguanas (Iguana iguana)

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

Concentração alveolar mínima do isoflurano em cães tratados com duas doses de morfina

This study aimed to evaluate the effects of intramuscular 0.5mg kg-1 (MOR0.5) and 1.0mg kg-1 (MOR1.0) morphine premedication on the minimum alveolar concentration of isoflurane (ISOMAC) in dogs. Eighteen client-owned female dogs were scheduled for elective ovariohysterectomy. Dogs received intramuscular MOR0.5 or MOR1.0 as premedication and propofol IV for induction of anesthesia. Isoflurane was delivered for maintenance of anesthesia and dogs were maintained under normocapnia and normothermia. Determinations of the ISOMAC were conducted by use of the “up-and-down” method. Noxious stimulus (placement of Backhaus towel clamps, a midline skin incision and subcutaneous tissue dissection) was delivered approximately 50 minutes after premedication with MOR0.5 or MOR1.0. The calculated ISOMAC was 0.98±0.15% in MOR0.5 and 0.80±0.08% in MOR1.0. The ISOMAC was significantly lower in MOR1.0 compared with MOR0.5 (P=0.010). Results of this study suggested that intramuscular premedication with morphine 0.5 and 1.0mg kg-1 decreases the ISOMAC in a dose-related manner in dogs.O presente estudo objetivou avaliar os efeitos da administração intramuscular de 0,5mg kg-1 (MOR0,5) ou 1,0mg kg-1 (MOR1,0) de morfina sobre a concentração alveolar mínima do isoflurano (CAMISO) em cães. Dezoito cadelas de proprietários foram agendadas para ovário-histerectomia eletiva. As cadelas receberam MOR0,5 ou MOR1,0, como medicação pré-anestésica, e propofol IV para indução da anestesia. A manutenção da anestesia foi realizada com isoflurano em condições de normocapnia a normotermia. A determinação da CAMISO foi conduzida de acordo com o método “up-and-down”. O estímulo nociceptivo (colocação de pinças Backhaus, incisão da pele na linha média e dissecção de tecido subcutâneo) foi realizado aproximadamente 50 minutos após a administração de MOR0,5 ou MOR1,0. A CAMISO calculada foi 0,98±0,15% em MOR0,5 e 0,80±0,08% em MOR1,0. A CAMISO foi significativamente menor em MOR1,0 do que em MOR0,5 (P=0,010). Os resultados do estudo sugerem que a medicação pré-anestésica com morfina nas doses de 0,5 e 1,0mg kg-1, pela via intramuscular, resulta em redução dose-dependente na CAMISO em cães

Intracoelomic pressure and coelomic perfusion pressure in healthy tegus (Salvator merianae)

<div><p>ABSTRACT: The evaluation of intracoelomic pressure is very important, as many diseases can culminate with an increase in intracoelomic pressure and a consequent reduction in perfusion of the abdominal organs. The aim of this study was to measure the intracoelomic pressure and coelomic perfusion pressure in tegus (Salvator merianae). Twelve healthy tegus without sexual distinctions, weighing 1.64±0.39kg, were enrolled in this study. Intracoelomic pressure was measured using two methods: a handmade water column system and a pressure transducer connected to a multiparameter monitor. Coelomic perfusion pressure was determined by subtracting the intracoelomic pressure from the mean arterial pressure, which was measured using an oscillometric method. Intracoelomic pressure was 0mmHg (range, 0 - 0.5) according to the water column method and 2mmHg (range, 0 - 2.0) according to the pressure transducer. Coelomic perfusion pressure was 76mmHg (range, 62 - 105) according to the water column system and 82mmHg (range, 57 - 93) according to the pressure transducer. No significant difference was observed between the values obtained by the different measurement methods. Intracoelomic pressure value reported in this study might be useful in tegus, but the coelomic perfusion pressure should be used with caution, considering the blood pressure method that was used.</p></div

Minimum alveolar concentration of isoflurane in dogs administered a single intramuscular injection of racemic or S (+)-ketamine after premedication with acepromazine-morphine

ABSTRACT: The present study evaluated the minimum alveolar concentration of isoflurane (ISOMAC) in twenty three dogs premedicated with acepromazine (0.02mgkg-1) and morphine (0.5mgkg-1) and administered racemic (RK) or S(+)-ketamine (SK). Dogs randomly received a single dose (3mgkg-1, IM) of either RK or SK 15minutes after anesthetic induction with propofol. The ISOMAC was determined by the up-and-down method. Approximately 20 minutes after administration of RK or SK, a surgical noxious stimulus was applied and the response evaluated. The ISOMAC was 0.50±0.01% in the RK group (n=10) and 0.31±0.04% in the SK group (n=13). The ISOMAC was 38% lower in the SK group compared to the RK group. Results of the present study revealed that in dogs premedicated with acepromazine and morphine, IM administration of 3mgkg-1 ketamine approximately 20 minutes before the noxious stimulus produced clinically important reduction in the ISOMAC and the MAC-sparing effect was significantly greater with SK compared to RK

Minimum alveolar concentration of isoflurane in dogs administered two morphine doses

ABSTRACT: This study aimed to evaluate the effects of intramuscular 0.5mg kg-1 (MOR0.5) and 1.0mg kg-1 (MOR1.0) morphine premedication on the minimum alveolar concentration of isoflurane (ISOMAC) in dogs. Eighteen client-owned female dogs were scheduled for elective ovariohysterectomy. Dogs received intramuscular MOR0.5 or MOR1.0 as premedication and propofol IV for induction of anesthesia. Isoflurane was delivered for maintenance of anesthesia and dogs were maintained under normocapnia and normothermia. Determinations of the ISOMAC were conducted by use of the “up-and-down” method. Noxious stimulus (placement of Backhaus towel clamps, a midline skin incision and subcutaneous tissue dissection) was delivered approximately 50 minutes after premedication with MOR0.5 or MOR1.0. The calculated ISOMAC was 0.98±0.15% in MOR0.5 and 0.80±0.08% in MOR1.0. The ISOMAC was significantly lower in MOR1.0 compared with MOR0.5 (P=0.010). Results of this study suggested that intramuscular premedication with morphine 0.5 and 1.0mg kg-1 decreases the ISOMAC in a dose-related manner in dogs

Concentração alveolar mínima do isoflurano em cães tratados com duas doses de morfina

This study aimed to evaluate the effects of intramuscular 0.5mg kg-1 (MOR0.5) and 1.0mg kg-1 (MOR1.0) morphine premedication on the minimum alveolar concentration of isoflurane (ISOMAC) in dogs. Eighteen client-owned female dogs were scheduled for elective ovariohysterectomy. Dogs received intramuscular MOR0.5 or MOR1.0 as premedication and propofol IV for induction of anesthesia. Isoflurane was delivered for maintenance of anesthesia and dogs were maintained under normocapnia and normothermia. Determinations of the ISOMAC were conducted by use of the “up-and-down” method. Noxious stimulus (placement of Backhaus towel clamps, a midline skin incision and subcutaneous tissue dissection) was delivered approximately 50 minutes after premedication with MOR0.5 or MOR1.0. The calculated ISOMAC was 0.98±0.15% in MOR0.5 and 0.80±0.08% in MOR1.0. The ISOMAC was significantly lower in MOR1.0 compared with MOR0.5 (P=0.010). Results of this study suggested that intramuscular premedication with morphine 0.5 and 1.0mg kg-1 decreases the ISOMAC in a dose-related manner in dogs.O presente estudo objetivou avaliar os efeitos da administração intramuscular de 0,5mg kg-1 (MOR0,5) ou 1,0mg kg-1 (MOR1,0) de morfina sobre a concentração alveolar mínima do isoflurano (CAMISO) em cães. Dezoito cadelas de proprietários foram agendadas para ovário-histerectomia eletiva. As cadelas receberam MOR0,5 ou MOR1,0, como medicação pré-anestésica, e propofol IV para indução da anestesia. A manutenção da anestesia foi realizada com isoflurano em condições de normocapnia a normotermia. A determinação da CAMISO foi conduzida de acordo com o método “up-and-down”. O estímulo nociceptivo (colocação de pinças Backhaus, incisão da pele na linha média e dissecção de tecido subcutâneo) foi realizado aproximadamente 50 minutos após a administração de MOR0,5 ou MOR1,0. A CAMISO calculada foi 0,98±0,15% em MOR0,5 e 0,80±0,08% em MOR1,0. A CAMISO foi significativamente menor em MOR1,0 do que em MOR0,5 (P=0,010). Os resultados do estudo sugerem que a medicação pré-anestésica com morfina nas doses de 0,5 e 1,0mg kg-1, pela via intramuscular, resulta em redução dose-dependente na CAMISO em cães

Efeitos hemodinâmicos da anestesia em plano profundo com infusão intravenosa contínua de propofol ou propofol associado à lidocaína em cães

The hemodynamic effects of total intravenous anesthesia with propofol or propofol in combination with lidocaine were investigated in 12 dogs. In the P group (n=6), the dogs received a loading dose (LD) of 6mg kg-1 of propofol followed by a constant rate infusion (CRI) of 1.25mg kg-1 min-1. In the PL group (n=6), dogs received a LD of 6mg kg-1 of propofol and 1.5mg kg-1 of lidocaine followed by CRIs of 1.0mg kg-1 min-1 and 0.25mg kg-1 min-1 of propofol and lidocaine, respectively. The animals were instrumented for measurement of hemodynamic variables and bispectral index (BIS), recorded at 75, 90, 105 and 120 minutes during anesthesia. Cardiac index, stroke index, systolic, diastolic and mean arterial blood pressures were lower in the P group compared to the PL group (P<0.05). There were no significant differences between groups in heart rate, systemic vascular resistance index and BIS. Plasma concentrations of propofol were lower in group PL than in group P (medians of 5.7 to 6.1mg mL-1 in the P group versus 3.1 to 3.7mg mL-1 in the PL group). Measured lidocaine plasma concentrations (medians of 2.27 to 2.51mg mL-1) were in the range that result in analgesia and were below values that result in toxicity in dogs. The BIS values observed in the two groups of dogs were compatible with deep anesthesia (mean values of 43-46 and 45-49 in groups P and PL, respectively). Maintenance of deep anesthesia with lidocaine-propofol causes less cardiovascular depression than equipotent doses of propofol alone.Os efeitos hemodinâmicos da anestesia total intravenosa com propofol ou propofol associado à lidocaína foram estudados em 12 cães. No grupo P (n=6), os animais receberam bolus de 6mg kg-1 de propofol e infusão contínua de 1,25mg kg-1 min-1. No grupo PL (n=6), os animais receberam bolus de 6mg kg-1 de propofol e 1,5mg kg-1 de lidocaína, seguido de infusão de 1,0mg kg-1 min-1 e 0,25mg kg-1 min-1, dos mesmos fármacos, respectivamente. Os animais foram instrumentados para mensuração das variáveis hemodinâmicas e do índice bispectral (BIS), aos 75, 90, 105 e 120 minutos de anestesia. Foram observados valores menores de índice cardíaco, índice sistólico, pressões arteriais sistólica, diastólica e média no grupo P do que no grupo PL (P<0,05). Não foram observadas diferenças entre os grupos na frequência cardíaca, índice de resistência vascular sistêmica e BIS. As concentrações plasmáticas de propofol foram menores no grupo PL do que no grupo P (medianas de 5,7 a 6,1µg mL-1 no grupo P versus 3,1 a 3,7µg mL-1 no grupo PL). As concentrações plasmáticas de lidocaína (medianas de 2,27 a 2,51µg mL-1) mensuradas encontram-se na faixa que resulta em analgesia e abaixo de valores que resultam em toxicidade em cães. Os valores de BIS obtidos nos dois grupos foram compatíveis com plano profundo de anestesia (médias de 43 a 46 e 45 a 49 nos grupos P e PL, respectivamente). A manutenção da anestesia em plano profundo com lidocaína-propofol causa menor depressão cardiovascular do que a anestesia com dose equipotente de propofol isoladamente