People with autism spectrum disorder often suffer from hyperactivity. It disrupts sleep, gets in a way of focusing on important daily tasks and makes person struggle with studying, working and so on. Now scientists from UCL, Yale and University of California have conducted a study with zebrafish that shows that the hormone oestrogen may help alleviate some of the negative effects of autism spectrum disorder.
Because oestrogen is female sex hormone scientists now are very intrigued by the results, because ASD is much more common in men than women. Oestrogen helped specially developed zebrafish to calm down during the night and sleep better. Scientists say that these results will eventually help battle the hyperactivity, because now they can research the brain pathways affected by the autism spectrum disorder.
Researchers conducted experiments with zebrafish genetically designed for this purpose. Fish were designed to have a mutation in the CNTNAP2 gene, which has been associated with human ASD. They are also transparent, which allows scientists to visualize brain development and activity with markers.
Scientists found out that plant-derived oestrogen biochanin A and the human sex hormone β-estradiol are the most effective at controlling the night time hyperactivity and do not affect day time activity of the fish. Unlike the drug, called risperidone, which is currently used to treat hyperactivity, but also affects day time activity.
Dr Ellen Hoffman, first author of the study, explained: “this research helps scientists to understand the function of an autism risk gene in the developing brain, which is important for understanding the biology of autism. The mechanism of action of the oestrogens on zebrafish behaviour remains unknown and there is considerably more work to do before these findings can be applied to humans.”
Scientists are comparing how normal and specially modified zebrafish respond to certain compounds in order to find out specific pathways involved in sleeplessness at night. Now it is already clear that drugs battling hyperactivity at night time have to be selective and biochanin A and β-estradiol manage exactly that. Now scientists will see how these substances affect other genetic mutations linked to autism spectrum disorder and then will continue their tests with mammal models.