Hyperammonaemia induces mitochondrial dysfunction and neuronal cell death

•Low concentrations of ammonia induce mitochondrial dysfunction, overproduction of ROS, and cell death in primary neurons.•Hyperammonaemia in cirrhotic rats leads to ROS and LP overproduction, which was prevented by the ammonia scavenger OP.•In neurons from cirrhotic rats, hyperpolarisation of Δψm was observed, which was restored by OP treatment.•In a rat model of cirrhosis, profound neuronal loss was observed in the hippocampus.