Abstract: Objective: To investigate the effects of histamine in water environment on the development of zebrafish larvae and its locomotor function. Methods: Newborn fertilized embryos of zebrafish were incubated and fed in gradient concentration of histamine solution (histamine concentrations were 0, 1.25, 2.5, 5, 10 and 20 mmol•L-1, respectively, 0 mmol•L-1 group as blank group). The hatching rate of zebrafish embryos and deformity rate of zebrafish larvae were calculated on the 3 day post-fertiliaztion (dpf) and 4 dpf respectively. The photos of deformed morphology of zebrafish larvae were collected at 4 dpf. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of histamine H1R, H2R and H3R type receptors. Swimming tracing was used to detect the motor function of non-deformed zebrafish larvae in 0, 5 and 20 mmol•L-1 group. Results：The aberration rate of zebrafish larvae increased with the higher concentration of histamine in water while the hatching rate was not affected in each group. Histamine treatment in water induced abnormal development of heart as well as body abnormalities of curving and short tail during the development of zebrafish larvae. Compared to the blank group, the motor function of zebrafish larvae in 5 and 20 mmol•L-1 group was significantly inhibited (P <0.01). The expression of H2R and H3R receptors in 5 and 20 mmol•L-1 was significantly decreased (P < 0.01 or P < 0.001). Conclusion: Histamine treatment in water environment leads to deformation of zebrafish larvae during development and inhibits motor function of larvae.

Key words: histamine, zebrafish（Danio rerio）, development, locomotor function