Benzodiazepine tranquilizers abolish the stress-induced increase of the brain ghrelin level in DANIO RERIO

Danio rerio has firmly established itself as a successful model for research in many areas of biology and medicine, first of all for developing new medicines.

The aim of our study was to evaluate ghrelin level in zebrafish brain after stress and after phenazepam usage on stressed fish.

Methods. In our study 96 Danio rerio, predator Cichlasoma nicaraguensis have been used. The fish have been kept at a normal room temperature (22–23 °C) with standard feeding time (twice per day). The level of neuropeptides has been tested by ELISA test. During experiment a fish has been firstly placed in a beaker with a dissolved pharmacological substance, then has been transferred into a tank with predator. In the end of experiment, it has been put into a novel tank for 6 min. The decapitation has been made. The brain has been divided into three anatomical parts: telencephalon just behind the olfactory bulb, the middle part – corpora bigemia and cerebellum, which is situated behind the corpora bigemia. After that the material for ELISA test was made using GhrelinFISH, MyBioSource ELISA kit.

Results. In the control group ghrelin has been determined only in the cerebellum in 57.14% of all fish. In the experiment with predator ghrelin has been found in all tested brain parts of fish, but in the telencephalon there was the highest level. In the experiment with phenazepam usage only and phenazepam administration after predator stress, the ghrelin value has not been determined at all.

Conclusion. Thus we have found out that the ghrelin value increases after predator stress and the drug phenazepam eliminated it completely after its administration. We may suppose that the administration of anxiolytics such as phenazepam can reduce the anxiety in Danio rerio.