Comparison of anxiolytic effects of mammalian and bony fish kisspeptins in <dfn>Danio rerio</dfn>

Abstract

In our previous work, we suggested that analogues of mammalian kisspeptin Kiss1 reduce anxiety-phobic reactions to novelty in Danio rerio. The most effective dose for the action of the studied analogues of kisspeptin corresponded to 0.1 mg per 1000 ml of water. In this work, it was shown that other analog of mammalian kisspeptin Kiss1 at a dose of 0.1 mg per 1000 ml of water also reduced the anxious behavior of Danio fish. The effect of Kiss 1 and Kiss 2 kisspeptins on the behavior of Danio rerio was also evaluated. In the novel test it was revealed that the number of freezings decreased by 2 times against the background of the introduction of kisspeptin 10, and by 3 times after the introduction of the analogue of kisspepin. An analogue of mammalian kisspeptin reduced the freezing time by 2 times. The length of the trajectory decreased by 2 times under the influence of the mammalian Kiss 1 analogue of kisspeptin. Also, against the background of the action of kisspeptin 10, the number of transitions to the upper part of the tank increased by 2 times. After the introduction of the kisspeptin analogue, the number of transitions to the upper part of the aquarium increased by 3 times. In the predator test, the number and time of freezings decreased by 1.5 times against the background of the action of mammalian kisspeptins. The length of the trajectory after the introduction of kisspeptin bony fish and kisspeptin 10 mammals increased. The length of the trajectory after the introduction of Kiss1 increased by 1.5 times. The length of the trajectory after the introduction of Kiss2 increased by 3 times. After the introduction of kisspeptin 10, the trajectory increased by 2 times, and the time spent in the lower part of the tank decreased by 2 times. Kisspeptins of bony fish also reduced anxiety-phobic reactions in fish, but to a lesser extent. Thus, kisspeptin 10 and an analogue of mammalian kisspeptin in response to the presentation of a predator had more significant effects on anxiety in Danio rerio compared to the action of kisspeptin bony fish Kiss 1 and Kiss 2. It is concluded that bony fish kisspeptins and mammalian kisspeptins can reduce anxiety-phobic reactions in Danio rerio, but mammalian kisspeptins are most effective. Bony fish kisspeptin Kiss 1 has an anxiolytic effect in contrast to Kiss 2, which suggests that it affects the reduction of fear, and Kiss 2 seems to be responsible for social and sexual behavior. The results support the hypothesis that kisspeptins 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.