Behavioural responses of zebrafish with sound stimuli in microfluidics.

Neuronal activities of the human brain responsible for cognitive features have been theorized through several animal models that exhibited various complementary spatial learning modes by generating a flexible repertoire of behavioral strategies. However, for such studies associated with a neurodegenerative disease, which can be further manipulated to provide therapeutic strategies, the animal models employed in their developmental stages have been preferred over the adult ones. This pilot work was incepted to underscore the spatial memory capabilities that strengthened the intricate mechanism of memory acquisition potential in one of the low-order evolutionarily conserved species, such as zebrafish larvae. Initially, a reliable and more easily reproducible microfluidic platform integrating simple and intricate paths was designed to learn and test the spatial information in zebrafish larvae of 4-6 d.p.f. under non-invasive acoustic stimuli. Further, to acquire spatial information as the representation of spatial memory formation in zebrafish larvae, the acoustic startle responses were evaluated by quantifying various dynamic behaviors under distinct operating parameters. After significant conditioning sessions, the spatial memory was tested by employing variable 'freezing'. By the end of the 30 min-long test session, 6 d.p.f. larvae were found to exhibit the highest value of freezing of approximately 43% and 20% in the short and long paths, respectively. Even though a substantial rate of memory loss was observed, it can be envisaged to serve several behavioral strategies that process the dynamic cognitive memory among distinct spatiotemporal environments. Further, the proposed behavioral paradigm had the advantage of being more adaptable and reliably replicable by other researchers. As a consequence, different hypotheses can be readily tested to generate more reproducible findings towards distinct neurobehavioral characteristics. Therefore, the proposed paradigm for the consolidation of spatial memory based on the non-invasive spatial avoidance strategies could provide an enduring framework of reference for behavioral studies using zebrafish larvae.

[Study on the correlation between hypertension and the indexes of vascular endothelial function among people living in the community].

OBJECTIVE: To study the features of hypertension and vessel endothelium functional parameter in people living at the community level as well as the risk factors of hypertension. Differences of angiotensin II (Ang II ), prostacyclin (PGI2) and nitric oxide (NO) among normal group and three hypertension groups were also studied. METHODS: By cluster sampling, 1134 adult Han people were selected from the residential communities. Medical history was documented and measurements of body height, body weight, waist circumference, hip circumference and blood pressure were performed. Serum NO levels were determined by cadmium reduction method while plasma Ang II and PGI2 concentration were determined by radioimmunoassay. SPSS 13.0 was used for data analysis. RESULTS: The total ratio of hypertension from people living at the community was 44.5%, with the standardized prevalence of hypertension as 15.3%. With the increase of age, the prevalence of hypertension also increased. Overweight and obesity seemed to be independent risk factors for hypertension. History of smoking and drinking and gender did not enter the logistic equation for hypertension. The amount of plasma Ang II concentration of the three hypertension groups was significantly lower than that in the normal group while the lowest group appeared to from the one that hypertension was under control. The NO and PGI2 levels of the two groups whose hypertension had been known were significantly higher than in the normal group while the difference between the group whose hypertension had not been measured and the normal group was not found. CONCLUSION: The prevalence of hypertension had been increasing. Control of body weight seemed to be a useful way for prevention of hypertension. We assumed that the negative feedback regulation of renin-angiotonin-aldosterone system in hypertension patient still existed which called for the research on the mechanism of hypertension.