Washington : Since most fish lack eyelids, many people have wondered whether they can even nod off. Now, a Stanford University study has found that fish do snooze at night.
What's more, like humans they also suffer from insomnia.
Scientists led by Philippe Mourrain, PhD, conducted their research on mutant Zebrafish in which the hypocretin system, which plays a key role in providing sleep to fish, was disrupted.
First author on the study Tohei Yokogawa, PhD, found that when kept awake, overall sleep decreased 30 percent in mutant fish, and when they finally did drift off, they remained asleep only half as long as normal fish.
The relationship between the hypocretin system and other sleep regulatory brain systems in zebrafish were also examined in the study.
Differences in expression patterns in the brain were also found, which may explain the differences in behavioural effects.
Emmanuel Mignot, MD, PhD, professor of psychiatry and behavioural sciences and a co-researcher in the study provided proof that zebrafish are a powerful new animal model for studying sleep disorders.
This he attributes to the fact that not only do zebrafish have backbones -thereby better representing the human nervous system, but that their young reveal many details because they are see-through.
"The fact that zebrafish larvae are transparent means you can look directly at their neuronal network, even in living fish," Mignot said.
"The idea is to try to use this as an entry point to understand the neurobiology of sleep regulation," he said.
The study is published in Biology.
