Effects of kisspeptin analogues on the behavior of <i>Danio rerio</i>

Abstract

BACKGROUND: Previously has been shown that fish kisspeptin 1 (Kiss1) acts on the brains serotonin system to reduce anxiety-phobic reactions in Danio rerio. The kissspeptin gene (kiss1) of teleost fish is also a conservative orthologue of the kissspeptin gene (KISS1/Kiss1) of mammals. AIM: In this work we investigated the possible anxiolytic effect of mammalian kisspeptin analogs Kiss1 in Danio rerio in comparison with antidepressants of the serotonin-type of action. MATERIALS AND METHODS: A novelty test was used: the fish was first placed in a beaker with a dissolved pharmacological substance (or H2O), and then in a viewing tank for 6 min, where the trajectory of movement, the length of the path, the number of movements to the upper part of the tank, the time spent in the lower part of the tank, number and time of the freezing were automatically recorded. RESULTS: It is shown that, in response to the novelty of being placed in a viewing tank, fish react by moving to the bottom, increasing friezing, and reducing the number of movements to the upper half of the tank. Against the background of antidepressants clomipramine, paroxetine or trazodone (0.51 mg per 1 l of water), the fish were not only in the lower, but also in the upper part of the viewing tank. The average path length did not change significantly. The time in the lower part of the tank decreased by more than 2 times compared with the control group of animals and showed a dose-dependent effect. The number of movements to the upper part of the tank per experience increased significantly. Mammalian kisspeptin analogues Cloud Clone (USA) in a dose 0.011 mg per 1 l of water caused a similar patterns of behavior in fish in response to novelty. At the same time, the effects of kisspeptin analogs were lower than those of antidepressants. The most effective dose for the action of the studied kisspeptin analogs was 0.1 mg per 1 l of water. CONCLUSIONS: Thus, mammalian kisspeptin analogs Kiss1 reduce anxiety-phobic responses to novelty in Danio rerio. Data on the unidirectional effects of mammalian kisspeptin analogs and serotonin-type antidepressants support the potential role of Kiss1 in modulating serotonin-dependent behaviours in Danio rerio. The data obtained support the hypothesis that kisspeptin may be involved in the regulation of anxiety-phobic states, apparently to maintain the emotional aspects of reproductive behavior, such as sexual motivation and arousal.