Exposição crônica ao cloridrato de metformina e à glibenclamida causa alterações comportamentais, glicêmicas e de mortalidade em Hemigrammus caudovittatus e Danio rerio / Chronic exposure to metformin chloridrate and glibenclamide causes behavioral, blood glucose and mortality changes of Hemigrammus caudovittatus and Danio rerio

Hemigrammus caudovittatus e Danio rerio foram expostos aos hipoglicemiantes orais (HOs) cloridrato de metformina a 40µg/L e 120µg/L e glibenclamida a 0,13µg/L e 0,39µg/L durante 100 dias. Foram avaliados os efeitos tóxicos dos fármacos em relação ao peso, ao comportamento animal, à glicemia e à mortalidade. H. caudovittatus expostos à menor concentração dos fármacos apresentaram aumento significativo (P<0,05) no evento Respiração Aérea. Ainda, foi observado aumento no comportamento Descansar quando os animais foram expostos à glibenclamida a 0,39µg/L. Em D. rerio expostos ao cloridrato de metformina a 120µg/L, foi observado aumento (P<0,05) no comportamento Descansar. A glibenclamida provocou redução (P<0,05) na glicemia de H. caudovittatus. Ambos os fármacos causaram efeito letal na espécie D. rerio, contudo a glibenclamida foi mais tóxica, causando 100% de mortalidade em 30 dias de exposição. Os animais que vieram a óbito apresentaram congestão nos arcos branquiais e hemorragia. Os HOs foram desenvolvidos para apresentarem efeitos fisiológicos em mamíferos, entretanto efeitos tóxicos foram encontrados nas duas espécies de peixe estudadas. Isso levanta a preocupação sobre possíveis efeitos tóxicos de HOs e sobre quais métodos serão utilizados para a sua degradação no ambiente aquático.(AU)

Hemigrammus caudovittatus and Danio rerio were exposed to oral hypoglycemic drugs (HOs) metformin hydrochloride at 40µg/L and 120µg/L and to glibenclamide at 0.13µg/L and 0.39µg/L during 100 days. Toxic effects of the drugs were evaluated based on weight, animal behavior, blood glucose and mortality. H. caudovittatus exposed to lowest concentration of the drugs showed significant increase (P< 0.05) in the Air breathing event. Furthermore, increase in Rest event was observed when animals were exposed to glibenclamide at 0.39µg/L. An increase (P< 0.05) in the frequency of Rest behavior in the D. rerio exposed to metformin hydrochloride at 120µg/L was observed. Glibenclamide caused decrease (P< 0.05) in the blood glucose of H. caudovittatus. Both drugs caused lethal effect against D. rerio. Nevertheless, glibenclamide was more toxic causing 100% of mortality after 30 days of exposure. The animals that died showed congestion on the branchial arches and hemorrhage. The HOs were developed to have physiological effects in mammals. However, toxic effects were found in both species of fish studied. This raises concerns about possible toxic effects of HOs and what methods will be used for their degradation in the aquatic environment.(AU)

Pharmacological characterization of venoms from three theraphosid spiders: Poecilotheria regalis, Ceratogyrus darlingi and Brachypelma epicureanum

Background Tarantulas (Theraphosidae) represent an important source of novel biologically active compounds that target a variety of ion channels and cell receptors in both insects and mammals. In this study, we evaluate and compare the pharmacological activity of venoms from three taxonomically different theraphosid spiders bred in captivity: Poecilotheria regalis, an aggressive arboreal tarantula from southeastern India; Ceratogyrus darlingi, an aggressive tarantula from southern Africa; and Brachypelma epicureanum, a docile tarantula from the Yucatan dry forest of Mexico. Prior to this study, no research had been conducted with regard to the composition and pharmacological activity of these venoms. Methods The pharmacological characterization of the venoms was described for the first time by the assessment of their toxicity in crickets (LD50) along with their nociceptive (by using the formalin test), hyaluronidase, phospholipase A2, edematogenic and caseinolytic activity. Results P. regalis and B. epicureanum venoms induced a similar lethal effect on crickets (LD50 = 5.23 ± 3.1 and 14.4 ± 5.0 μg protein/g 48 h post-injection, respectively), whereas C. darlingi venom (119.4 ± 29.5 μg protein/g 48 h post-injection) was significantly less lethal than the other two venoms. All three venoms induced similar edematogenic activity on rats but did not induce nociceptive behavior. The assessment of enzymatic activity indicated that P. regalis venom induces significantly higher hyaluronidase activity (27.6 ± 0.9 TRU/mg) than both C. darlingi (99.7 ± 1.9 TRU/mg) and B. epicureanum (99.6 ± 1.6 TRU/mg); these latter venoms did not display phospholipase A2or caseinolytic activity. Conclusions This study demonstrates that these theraphosid spiders of different habitats produce venoms with different activities. P. regalis venom displays a high level of hyaluronidase activity, which may be associated with its potentially medically significant bite.

Exposure to 50 Hz electromagnetic field changes the efficiency of the scorpion alpha toxin

Background Extremely low-frequency (50 Hz) electromagnetic field (ELF-EMF) is produced by electric power transmission lines and electronic devices of everyday use. Some phenomena are proposed as first effects of ELF-EMF: the discrete changes in the membrane potential and the increase of the calcium channel activity as well as the intracellular concentration of Ca 2+ . Interaction of the scorpion alpha toxin with the sodium channel depends on the orientation of the charges and may be perturbed by changes in the membrane polarization. The toxin induces overexcitability in the nervous system and an increase in the neurotransmitters released with different consequences, mainly the paralysis of muscles. We assumed that the exposure to ELF-EMF 0.7 mT will change the effects of the insect selective scorpion alpha toxin (recombinant LqhIT from Leiurus quinquestriatus hebraeus) at the level of the cercal nerve function, the synaptic transmission and on the level of entire insect organism. Taking into account the compensatory mechanisms in organisms, we tested in addition ten times higher ELF-EMF on whole insects.Methods Experiments were performed in vivo on cockroaches (Periplaneta americana) and in vitro on isolated cockroach abdominal nerve cord with cerci. In biotests, the effects of LqhIT (10 8 M) were estimated on the basis of the insect ability to turn back from dorsal to ventral side. Three groups were compared: the control one and the two exposed to ELF-EMF 0.7 and 7 mT. Bioelectrical activity of the cercal nerve and of the connective nerve that leaves the terminal abdominal ganglion was recorded using extracellular electrodes. LqhIT (5 × 10 8 M) induced modifications of neuronal activity that were observed in the control cockroach preparations and in the ones exposed to ELF-EMF (0.7 mT). The exposure to ELF-EMF was carried out using coils with a size appropriate to the examined objects.Results The exposure to ELF-EMF (0.7 mT) modified the effects of LqhIT (5 × 108 M) on activity of the cercal nerve and of the connective nerve. We observed a decrease of the toxin effect on the cercal nerve activity, but the toxic effect of LqhIT on the connective nerve was increased. Biotests showed that toxicity of LqhIT (10 8 M) on cockroaches was reduced by the exposure to ELF-EMF (0.7 and 7 mT).Conclusions The exposure to 50 Hz ELF-EMF modified the mode of action of the anti-insect scorpion alpha toxin LqhIT at cellular level of the cockroach nervous system and in biotests. Toxin appeared as a usefull tool in distinguishing between the primary and the secondary effects of ELF-EMF.

Allosteric interactions between receptor site 3 and 4 of voltage-gated sodium channels: a novel perspective for the underlying mechanism of scorpion sting-induced pain

Background BmK I, a site-3-specific modulator of voltage-gated sodium channels (VGSCs), causes pain and hyperalgesia in rats, while BmK IT2, a site-4-specific modulator of VGSCs, suppresses pain-related responses. A stronger pain-related effect has been previously attributed to Buthus martensi Karsch (BmK) venom, which points out the joint pharmacological effect in the crude venom.Methods In order to detect the joint effect of BmK I and BmK IT2 on ND7-23 cells, the membrane current was measured by whole cell recording. BmK I and BmK IT2 were applied successively and jointly, and the synergistic modulations of VGSCs on ND7-23 cells were detected.Results Larger peak I Na and more negative half-activation voltage were elicited by joint application of BmK I and BmK IT2 than by application of BmK I or BmK IT2 alone. Compared to the control, co-applied BmK I and BmK IT2 also significantly prolonged the time constant of inactivation.Conclusions Our results indicated that site-4 toxin (BmK IT2) could enhance the pharmacological effect induced by site-3 toxin (BmK I), suggesting a stronger effect elicited by both toxins that alone usually exhibit opposite pharmacological effects, which is related to the allosteric interaction between receptor site 3 and site 4. Meanwhile, these results may bring a novel perspective for exploring the underlying mechanisms of scorpion sting-induced pain.

Evaluation of the acute and subchronic oral toxicity of ethanol extract from Valeriana pavonii species in Wistar rats / Evaluación de la toxicidad oral aguda y sub-crónica del extracto etanólico de la especie Valeriana pavonii en ratas Wistar

Introduction: One of the most frequent problems found in medicinal plants is the absence of clinical, toxicological, and pharmacological studies. Valeriana pavonii is one of the species used in Colombia as an anxiolytic. Further study of this specie is rendered to add information in the toxicological area. Objective: The acute and subchronic oral toxicity of V. pavonii ethanolic extract was evaluated in Wistar rats of both sexes. Materials and methods: The rats were distributed into four groups: the control group received the vehicle (0.5 mL/100 g of corporal weight) and the other three groups received increasing levels of the dosage for 90 days to evaluate characteristics like physical exam, laboratory test (blood chemistry and haematology), and anatomopathological findings. Results: This study reveals that there were no signs of toxicity, mortality, or significant alterations attributable to the ethanolic extract of V. pavonii. Conclusions: The Not Observed Adverse Effect Levels (NOAEL) of V. pavonii ethanolic extract were 2000 and 1000 mg/kg of body weight for the acute and subchronic toxicity studies, respectively.

Introducción: Uno de los problemas más frecuentes asociados con el uso de plantas medicinales es la ausencia de evidencias farmacológicas, toxicológicas y clínicas. Valeriana pavonii es una de las especies más utilizadas popularmente en Colombia con fines ansiolíticos. Es necesario avanzar en el estudio de esta especie para aportar información en el campo toxicológico. Objetivos: Evaluar la toxicidad oral aguda y sub-crónica del extracto etanólico de V. pavonii en ratas Wistar de ambos sexos. Materiales y métodos: En cada uno de los estudios se distribuyeron ratas en cuatro grupos; un grupo control que recibió únicamente vehículo (0.5 ml/100 g de peso corporal) y tres grupos correspondientes a niveles crecientes de dosis, así: para el estudio de toxicidad aguda se administraron en dosis única 20, 200 y 2000 mg/kg con un período de observación de 14 días y para el de toxicidad sub-crónica, dosis diarias de 250, 500 y 1000 mg/kg durante 90 días. Se evaluaron los parámetros de examen físico, los exámenes de laboratorio (química sanguínea y hematología) y el estudio anatomopatológico. Resultados: No se presentaron signos de toxicidad, letalidad ni alteraciones significativas atribuibles al consumo del extracto etanólico de V. pavonii, según el examen físico, el examen anatomopatológico y el análisis de las pruebas de química sanguínea y hematología. Conclusiones: Los valores de nivel sin efectos adversos observados (NOAEL) del extracto etanólico de V. pavonii, fueron 2000 y 1000 mg/kg de peso corporal para los estudios de toxicidad aguda y sub-crónica, respectivamente. No se encontraron valores de nivel más bajo de efecto adverso observado (LOAEL).

Aspectos clínicos da intoxicação experimental pelas favas de Stryphnodendron fissuratum (Leg. Mimosoideae) em caprinos / Clinical aspects of the experimental poisoning by the pods of Stryphnodendron fissuratum (Leg. Mimosoideae) in goats

Com o objetivo de caracterizar o quadro clínico da intoxicação por Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) em caprinos, administraram-se as favas dessa planta a oito caprinos, por via oral forçada em doses únicas e a outros dois caprinos, em doses fracionadas. A menor dose que causou sinais clínicos e morte foi a de 10g/kg. Doses de 20g/kg e 40g/kg causaram sinais acentuados e doses únicas de 5g/kg não provocaram sinais. Doses fracionadas de 5g/kg durante quatro dias, totalizando 20g/kg provocaram sinais acentuados e morte. Em ambos os grupos, os primeiros sinais de intoxicação foram observados a partir do primeiro dia de experimento e a evolução variou de 4-25 dias. A doença caracterizou-se principalmente por alterações digestórias e nervosas que consistiram em anorexia, desidratação, hipomotilidade e atonia ruminal, timpanismo, gemidos constantes, dor à percussão abdominal, fezes com muco, ranger de dentes, apatia, ataxia, dismetria, tremores de cabeça, tremores musculares, fraqueza com o andar cambaleante e trôpego, acentuada depressão e decúbito esternal ou lateral prolongado e morte. Alguns animais apresentaram acentuada queda de pêlos na região dorsal; apenas um caprino apresentou fezes líquidas, marrom-escuras e fétidas. Outros sinais incluíram perda de fluido ruminal durante a ruminação, sialorréia, exsudato nasal seroso e lacrimejamento. As provas de função hepática e renal revelaram alterações discretas. As concentrações séricas de aspartato aminotransferase encontraram-se levemente aumentadas e as de creatinofosfocinase muito aumentadas.

In order to confirm the susceptibility of goats to the poisoning by Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) and to characterize the clinical disease, the pods of the plant were given orally to each of eight young goats and in fractioned doses to other two. The lowest lethal dose was 10g/kg. The same dose was the lowest that induced disease. Doses of 20g/kg and 40g/kg caused pronounced clinical signs and doses of 5g/kg did not caused signs. Fractioned doses of 5g/kg during four days also caused pronounced signs. In each groups the first signs of poisoning were observed from the first day of experiments and the changes ranged from 4-25 days. The disease was characterized mainly by digestive and nervous disorders. Clinical signs were partial to complete anorexia, dehydration, decrease in ruminal activity up to atonia, tympanism, constant vocalizations, grinding of the teeth pain up on abdominal palpation, apathy, ataxia, depression, dysmetria, head and muscle tremors, weakness, difficulty in rising, sternal or lateral recumbency and death. Some goats presented extense hair loss in the skin of the dorsum; one goat presented liquid and black fetid feces. Other signs included loss of ruminal fluid during rumination, drooling, serous nasal and ocular discharges. Liver and kidney function tests had resulted in slight changes. AST serum levels were slightly increased and creatine phosphokinase levels were highly increased. These changes can associated to the effects of triterpenic saponins contained in the S. fissuratum pods.

Aspectos clínicos da intoxicação experimental pelas favas de Stryphnodendron fissuratum (Leg. Mimosoideae) em caprinos / Clinical aspects of the experimental poisoning by the pods of Stryphnodendron fissuratum (Leg. Mimosoideae) in goats

Com o objetivo de caracterizar o quadro clínico da intoxicação por Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) em caprinos, administraram-se as favas dessa planta a oito caprinos, por via oral forçada em doses únicas e a outros dois caprinos, em doses fracionadas. A menor dose que causou sinais clínicos e morte foi a de 10g/kg. Doses de 20g/kg e 40g/kg causaram sinais acentuados e doses únicas de 5g/kg não provocaram sinais. Doses fracionadas de 5g/kg durante quatro dias, totalizando 20g/kg provocaram sinais acentuados e morte. Em ambos os grupos, os primeiros sinais de intoxicação foram observados a partir do primeiro dia de experimento e a evolução variou de 4-25 dias. A doença caracterizou-se principalmente por alterações digestórias e nervosas que consistiram em anorexia, desidratação, hipomotilidade e atonia ruminal, timpanismo, gemidos constantes, dor à percussão abdominal, fezes com muco, ranger de dentes, apatia, ataxia, dismetria, tremores de cabeça, tremores musculares, fraqueza com o andar cambaleante e trôpego, acentuada depressão e decúbito esternal ou lateral prolongado e morte. Alguns animais apresentaram acentuada queda de pêlos na região dorsal; apenas um caprino apresentou fezes líquidas, marrom-escuras e fétidas. Outros sinais incluíram perda de fluido ruminal durante a ruminação, sialorréia, exsudato nasal seroso e lacrimejamento. As provas de função hepática e renal revelaram alterações discretas. As concentrações séricas de aspartato aminotransferase encontraram-se levemente aumentadas e as de creatinofosfocinase muito aumentadas.

In order to confirm the susceptibility of goats to the poisoning by Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) and to characterize the clinical disease, the pods of the plant were given orally to each of eight young goats and in fractioned doses to other two. The lowest lethal dose was 10g/kg. The same dose was the lowest that induced disease. Doses of 20g/kg and 40g/kg caused pronounced clinical signs and doses of 5g/kg did not caused signs. Fractioned doses of 5g/kg during four days also caused pronounced signs. In each groups the first signs of poisoning were observed from the first day of experiments and the changes ranged from 4-25 days. The disease was characterized mainly by digestive and nervous disorders. Clinical signs were partial to complete anorexia, dehydration, decrease in ruminal activity up to atonia, tympanism, constant vocalizations, grinding of the teeth pain up on abdominal palpation, apathy, ataxia, depression, dysmetria, head and muscle tremors, weakness, difficulty in rising, sternal or lateral recumbency and death. Some goats presented extense hair loss in the skin of the dorsum; one goat presented liquid and black fetid feces. Other signs included loss of ruminal fluid during rumination, drooling, serous nasal and ocular discharges. Liver and kidney function tests had resulted in slight changes. AST serum levels were slightly increased and creatine phosphokinase levels were highly increased. These changes can associated to the effects of triterpenic saponins contained in the S. fissuratum pods.

Teste de toxicidade e criopreservação de folículos pré-antrais ovinos isolados utilizando Glicerol, Etilenoglicol, Dimetilsulfóxido e Propanodiol / Toxicity test and cryopreservation of sheep isolated preantral follicles using glycerol, ethylen glycol, dimethil sulfoxyde and propanediol

O objetivo deste estudo foi avaliar foliculos pré-antrais (FOPA) ovinos isolados após sua exposição e criopreservação utilizando glicerol (GLI), etilenoglicol (EG), propanodiol (PROH) ou dimetilsulfóxido (DMSO) a 1,5 e 3,0 M. Cada par ovariano de 5 ovelhas sem raça definida foi coletado em abatedouro local e submetido ao isolamento folicular. Da suspensão obtida, uma aliquota foi imediatamente destinada à análise da viabilidade folicular com o auxílio do corante vital azul de trypan. O restante da suspensão foi dividida em 16 aliquotas de 0,9 mL, suspensas (v/v) em MEM+ com EG, DMSO, GLI ou PROH a 1,5 ou 3,0 M, para teste de toxicidade e criopreservação. Após o término de cada tratamento, a viabilidade folicular foi analisada e os FOPA considerados viáveis se não corados ou não viáveis, quando corados. A análise dos dados mostrou que após o teste de toxicidade e criopreservação, em todos os crioprotetores e em ambas as concentrações, a percentagem de FOPA viáveis foi significativamente reduzida quando comparada ao controle. No teste de toxicidade, quando os crioprotetores foram comparados entre si nas mesmas concentrações, foram observadas percentagens signifIcativamente menores de FOPA viáveis no PROH 3,0 M (38,9%), apresentando-se, portanto, mais tóxico quando comparado aos demais crioprotetores. Após criopreservação, obteve-se percentagens significativamente maiores de foliculos pré-antrais viáveis quando o EG e o DMSO foram utilizados. Em conclusão, FOPA ovinos isolados podem ser criopreservados com sucesso utilizando-se D MSO e EG a 1,5 e 3,0 M.

The aim of this study was to evaluate isolated sheep preantral follicles (PF) after exposure and cryopreservation using glycerol (GLI), ethylene glycol (EG), propanediol (PROH) or dimethyl sulfoxide (DMSO) at 1.5 and 3.0 M. Each ovarian pair from 5 mixed breed adult sheeps was obtained at a local slaughterhouse and submited to follicular isolation. From the obtained suspension, one aliquot was immediately analysed with trypan blue. The remaining suspension was divided in 16 aliquots of 0.9 mL, suspended in (v /v) in MEM+with EG, DMSO, GLI or PROH at 1.5 or 3.0 M to the toxicity test and cryopreservation. After the end of each treatment, the follicular viability was analysed and the PF were classified as viable if not dyed or not viable if dyed with trypan blue. The analysis of the results showed that after the toxicity test and cryopreservation, using all cryoprotectants and at both concentrations, the percentage of viable PF was significandy reduced when compared to the control. At the toxicity test, when the cryoprotectants were compared at the same concentrations, the lowest percentage of viable preantral follicles was obtained when 3.0 M PRO H (38,9%) was used, being, more toxic when compared to the others cryoprotectants. After cryopreservation, significantly higher percentual of viable PF was observed when the EG and DMSO were used. In conclusion, sheep PF can be cryopreserved successfully using DMSO and EG at 1.5 and 3.0 M.