Zebrafish study reveals how disrupted microexons trigger chronic insomnia and hyperarousal

A new study has uncovered a biological link between disrupted neural microexons and severe sleep disturbances in zebrafish. The research shows that altered splicing of these tiny gene segments triggers hyperarousal, sensory hypersensitivity, and insomnia. These findings may also apply to mammals, including humans, due to shared evolutionary pathways. In zebrafish, abnormal microexon patterns lead to a persistent state of hyperarousal. This condition causes erratic swimming behaviour and chronic sleep loss. Scientists traced the issue to a spike in cAMP signalling within the forebrain, which overexcites neurons and drives daytime hyperactivity.

The team tested a chemical inhibitor to lower cAMP levels in the mutated fish. The treatment successfully normalised both swimming patterns and sleep. Conversely, when normal fish were given drugs to maintain high cAMP levels, they exhibited the same hyperaroused behaviour.

This sleep-deprivation mechanism mirrors patterns seen in fruit flies. The similarity suggests the pathway is conserved across species, including mammals. The study also highlights that microexon mis-regulation may explain sleep disturbances and anxiety in neurodevelopmental disorders such as autism and schizophrenia. The research provides a clear biological explanation for hyperarousal and insomnia linked to neural microexons. By targeting cAMP levels, scientists restored normal behaviour in zebrafish. These findings could guide future studies into similar mechanisms in humans and other mammals.