Reduction in activity by noxious chemical stimulation is ameliorated by immersion in analgesic drugs in zebrafish.

Research has recently demonstrated that larval zebrafish show similar molecular responses to nociception to those of adults. Our study explored whether unprotected larval zebrafish exhibited altered behaviour after exposure to noxious chemicals and screened a range of analgesic drugs to determine their efficacy to reduce these responses. This approach aimed to validate larval zebrafish as a reliable replacement for adults as well as providing a high-throughput means of analysing behavioural responses. Zebrafish at 5 days post-fertilization were exposed to known noxious stimuli: acetic acid (0.01%, 0.1% and 0.25%) and citric acid (0.1%, 1% and 5%). The behavioural response of each was recorded and analysed using novel tracking software that measures time spent active in 25 larvae at one time. Subsequently, the efficacy of aspirin, lidocaine, morphine and flunixin as analgesics after exposure to 0.1% acetic acid was tested. Larvae exposed to 0.1% and 0.25% acetic acid spent less time active, whereas those exposed to 0.01% acetic acid and 0.1-5% citric acid showed an increase in swimming activity. Administration of 2.5 mg l-1 aspirin, 5 mg l-1 lidocaine and 48 mg l-1 morphine prevented the behavioural changes induced by acetic acid. These results suggest that larvae respond to a noxious challenge in a similar way to adult zebrafish and other vertebrates and that the effect of nociception on activity can be ameliorated by using analgesics. Therefore, adopting larval zebrafish could represent a direct replacement of a protected adult fish with a non-protected form in pain- and nociception-related research.

Avaliação de extratos de quebra- pedra (Phyllanthus sp) frente à patógenos causadores de infecções no trato urinário / Evaluation of Phyllanthus sp extracts in face of Pathogen Causers of Urinary Treat Infections

RESUMO O trato urinário normalmente é estéril, no entanto, pode ser contaminado por agentes etiológicos provenientes da microbiota intestinal, dentre os mais comuns pode-se destacar a Escherichia coli. Os microrganismos estão se tornando cada vez mais resistentes a múltiplos antimicrobianos. É notória, portanto, a necessidade de encontrar novas substâncias com propriedades antimicrobianas. Portanto, foram avaliados diferentes extratos de Phyllanthus sp, frente a microrganismos causadores de infecções no trato urinário e comparadas as técnicas de hole-plate e disco difusão. Para ambas as técnicas avaliadas, o extrato de 72 horas mostrou melhor atividade antimicrobiana, na técnica de disco difusão, a bactéria mais sensível foi o Staphylococcus saprophyticcus, que apresentou CMI (Concentração Mínima Inibitória) de 15,84 mg/mL. Com a utilização da técnica de hole-plate, a bactéria mais sensível observada foi Staphylococcus aureus, com valor de CMI igual ao reportado anteriormente. Foi observado que os extratos alcoólicos obtiveram maior eficiência em relação às infusões, que a técnica de hole-plate revelou ser mais eficiente que a técnica de disco difusão e que os cocos Gram positivos foram mais susceptíveis quando comparadas aos bacilos Gram negativos e fungos.

ABSTRACT Commonly, the urinary treat is sterile, but it can also be contaminated by etiological agents from the intestinal treat, of which the Escherichiacoli is the most common one. These microorganisms are increasingly becoming more resistant to multiple antibiotics. It became necessary to find new substances with antimicrobial properties, so the purpose of this paper is to evaluate different Phyllanthus sp extracts- in face of microorganisms which cause the urinary treat infections- and compare it to the hole-plate and disk diffusion techniques. The 72 hours extraction showed better antimicrobial activity in both methods. Using disk diffusion, the most sensitive bacterium was the Staphylococcus saprophyticcus, with the MIC of 15,84 mg/mL. While using the technique of hole-plate, the most sensitive bacterium was the Staphylococcus aureus, with the same MIC of the previous cited bacterium. This study showed that the alcoholic extracts were more efficient than the infusions. It can also be observed that the hole-plate technique seems to be more efficient than the disk diffusion one, and the Gram positive cocci bacteria were more sensitive than the Gram negative bacilli and fungi.

Noxious compounds activate TRPA1 ion channels through covalent modification of cysteines.

The nervous system senses peripheral damage through nociceptive neurons that transmit a pain signal. TRPA1 is a member of the Transient Receptor Potential (TRP) family of ion channels and is expressed in nociceptive neurons. TRPA1 is activated by a variety of noxious stimuli, including cold temperatures, pungent natural compounds, and environmental irritants. How such diverse stimuli activate TRPA1 is not known. We observed that most compounds known to activate TRPA1 are able to covalently bind cysteine residues. Here we use click chemistry to show that derivatives of two such compounds, mustard oil and cinnamaldehyde, covalently bind mouse TRPA1. Structurally unrelated cysteine-modifying agents such as iodoacetamide (IA) and (2-aminoethyl)methanethiosulphonate (MTSEA) also bind and activate TRPA1. We identified by mass spectrometry fourteen cytosolic TRPA1 cysteines labelled by IA, three of which are required for normal channel function. In excised patches, reactive compounds activated TRPA1 currents that were maintained at least 10 min after washout of the compound in calcium-free solutions. Finally, activation of TRPA1 by disulphide-bond-forming MTSEA is blocked by the reducing agent dithiothreitol (DTT). Collectively, our data indicate that covalent modification of reactive cysteines within TRPA1 can cause channel activation, rapidly signalling potential tissue damage through the pain pathway.