Critical Effects on Akt Signaling in Adult Zebrafish Brain Following Alterations in Light Exposure

Area of Science:

• Neuroscience
• Chronobiology
• Zebrafish models

Background:

• Disrupted light cycles are linked to sleep disturbances, cognitive decline, and health disorders in humans and animals.
• Zebrafish, with their diurnal rhythm, are valuable models for studying neurophysiology and neuropathophysiology.

Purpose of the Study:

• To investigate the impact of altered, unpredictable light cycles on the adult zebrafish brain.
• To examine changes in heat shock protein-70 (HSP70) and Akt-GSK3β signaling pathways in response to light cycle disruption.

Main Methods:

• Adult zebrafish were exposed to altered light cycles for four days.
• Expression levels of HSP70, pSer473-Akt (protein kinase B), and pSer9-GSK3β (glycogen synthase kinase-3β) were measured in the telencephalon and optic tectum.
• The effect of environmental enrichment on these pathways was also assessed.

Main Results:

• Altered light exposure significantly decreased HSP70 expression in the optic tectum.
• pSer473-Akt levels were reduced in the telencephalon, and pSer9-GSK3β was reduced in both telencephalon and optic tectum.
• Environmental enrichment's positive effect on pSer473-Akt was attenuated by altered light exposure.

Conclusions:

• Unpredictable light exposure alters HSP70 expression in the zebrafish brain.
• Light cycle disruption dysregulates the Akt-GSK3β signaling pathway in adult zebrafish.
• These findings provide novel insights into the neurobiological effects of light cycle disruption.