Allosteric inhibition of muscle-type nicotinic acetylcholine receptors by a neuromuscular blocking agent pancuronium.

Muscle relaxants are indispensable for surgical anesthesia. Early studies suggested that a classical non-depolarizing muscle relaxant pancuronium competitively binds to the ligand binding site to block nicotinic acetylcholine receptors (nAChR). Our group recently showed that nAChR which has two distinct subunit combinations are expressed in zebrafish muscles, αßδε and αßδ, for which potencies of pancuronium are different. Taking advantage of the distinct potencies, we generated chimeras between two types of nAChRs and found that the extracellular ACh binding site is not associated with the pancuronium sensitivity. Furthermore, application of either 2 µM or 100 µM ACh in native αßδε or αßδ subunits yielded similar IC50 of pancuronium. These data suggest that pancuronium allosterically inhibits the activity of zebrafish nAChRs.

[Application of zebrafish model organism in the research of Chinese materia medica].

Zebrafish has become an important model organism in many fields of biomedical studies and been increasingly used in Chinese materia medica studies in recent years. This article summarized the achievements and prospect for zebrafish as a pharmacological and toxicological tool in the study and development of Chinese materia medica.

Data mining for chinese materia medica and pharmacological research.

Chinese materia medica (CMM) is becoming increasingly important in modern health care, with the potential for new or improved clinical protocols and reduction in treatment costs. Conventional approaches to drug discovery are based on knowledge of biological systems and screen phenotypes in the context of a whole organism. It will be valuable to identify the CMM that would induce certain biological responses (such as angiogenesis). The authors have developed a database that they plan to commercialize that contains traditional knowledge of Chinese medicine and pharmacology along with their own experimental data from controlled scientific observations by using the zebrafish as a model of CMM-induced pathology. The database is visualized and functions via the World Wide Web by subscription or license. The authors have also written software for personal digital assistant (PDA) devices that supports multiple users performing screening experiments worldwide. This provides a platform for the study of CMM, and data mining of this resource will help evaluate CMM in the context of experimental observations of biological aberrations.

Effects of Essential Oil from Thymus vulgaris on Viability and Inflammation in Zebrafish Embryos.

Innate immunity provides the initial response against pathogens and includes the inflammatory response. Regulation of the initiation and duration of neutrophil and mononuclear cell influx during inflammation determines both the successfulness of pathogen elimination and the level of resulting tissue damage. Zebrafish embryos provide excellent opportunities to visualize the inflammatory response. Neutrophil granules may be stained with Sudan black, and variation in neutrophil counts may be used to monitor the level of the response. Inflammation may be triggered by injuring the caudal fin, providing an opportunity for testing possible anti-inflammatory compounds in a whole-animal system. The use of homeopathic compounds as anti-inflammatory treatments is common in alternative medicine. Effects of unfractionated essential oil from Thymus vulgaris and its specific component, carvacrol, have been examined in cells in culture and in rodents. Our work extends this research to zebrafish, and includes toxicity and morphological studies as well as examination of anti-inflammatory effects following tail fin injury. Our results show that zebrafish are more sensitive to thyme oil compared to cells in culture, that cardiac defects arise due to thyme oil treatment, and that thyme oil reduces neutrophil infiltration during an inflammatory response.

Neurobehavioral assessment of Danio reriointoxicated by Mercury and the use of Mercurius solubilis

Mercury is used in various industrial. Part of Mercury's industrial waste is discharged into the environment, rivers and their tributaries, thus contaminating aquatic animals. Aim:to evaluate Mercury-induced behavioral changes in Zebrafish (Danio rerio) by the analysis of locomotor activity and parameters related to neurotoxicity and to verify whether ultra-diluted substances can decrease neurobehavioral effects and toxic. Methodology:The fishes were separated into 4 monitoring aquariums with 8 fishes each, with temperature, pH controlled, until the time of the toxicological experiments. 0.5 mL of Mercury 6cH, 30cH and distilled water (positive control) were added per liter of water in each aquarium containing 6 liters of water, then 3 mL of medication per aquarium, the white control received no medication and the toxic agent. After 1 hour the drugs were added, toxic mercury (200 µg/L), 4 mL per aquarium was added and remained so for 24 hours. All the experiment was run in blind, and the drugs identified by codes. The animals were subjected to behavioral tests (Open Field-locomotion; Vertical Open Field for neurotoxicity evaluation and Light and Dark Test), and each stage was recorded for later evaluation of movements and neurobehavioral changes. ANOVA was performed, followed by Tukey test, with p <0.05. Results: Mercury produced an anxiogenic effect in animals that were submitted to it without medication. In the vertical open field, there was an increase in erratic movements (1.25 ± 1.0) and tremors (0.87 ± 0.35) compared to the control (0.12 ± 0.35 and 0.25 ± 0.46 respectively), proving the toxic effect. Fishes which received the medication at 6 cH and 30 ch showed tremors and erratic movements similar to control. Conclusion:200 µg/L mercury in water can cause neurobehavioral disturbances in fishes, and animals receiving Mercurius6 cH and 30 cH ultra-diluted drug did not show neurotoxicity.