Can fish sleep? For a long time, scientists puzzled over this issue, but the results of a recent study showed that after a hectic night, fish like to take a nap. 
Do not be deceived by the fact that the eyes of the fish are always open: these living creatures also like to sleep at night and even take a nap in the morning.
Zebra danios (Danio rerio), like most other species of fish, do not have eyelids, so it is difficult to establish what they are doing in a passive state - they sleep or just rest.
But now, researchers have been able to prove not only the fact that the fish are sleeping, but also that these living creatures can suffer from insomnia, and also difficult to endure the forced wakefulness.
Regularly disturbing the peace of the fish of this species common in aquariums (a weak electric shock was used for this), the scientists were able to make them stay awake all night. And what did it turn out? Fish that have had a restless night, try to sleep off at the first opportunity.
Some of the individuals on which the experiment was carried out were carriers of a mutant gene that affects the sensitivity of the nervous system to hypocretins, hormonal substances that help fight sleep. The lack of hypocretins in the human body is considered the cause of narcolepsy.
Zebra danios with a mutant gene suffered from insomnia; it was found that they were able to sleep 30% less time than their counterparts with a normal gene. "Fish that are insensitive to hypocretins, sleep briefly and intermittently in the dark," the researchers reported in the online journal PLoS Biology.
Thanks to the study, scientists have learned more about the functions of molecules that regulate sleep. They hope that further experiments with zebra danios selected for experiments due to the similarity of their central nervous system with the corresponding organs of mammals will help penetrate into the mechanisms of sleep disorders in humans.
“Sleep disorders are widespread, but we don’t understand their mechanisms. In addition, there are a lot of hypotheses about how and why the brain goes into sleep. the researchers.
The observation of the fish was carried out by a group of scientists from the USA and France. It was found that when the fish fall asleep, their tail fins bend down and the fish themselves stay either on the surface of the water or at the bottom of the aquarium.
One of the participants in the study, Emmanuel Minho of Stanford University (USA), notes: "It is likely that we will draw valuable conclusions from this, which will help to figure out how — and perhaps why — natural evolutionary processes have developed sleep mechanisms, so universal phenomenon. "
Lewis Smith
www.inopressa.ru
And what did it turn out?
