Neonatal encephalopathy involving hypoxia-ischemia is a leading cause of neonatal mortality, affecting ~3-4/1000 neonates and can lead to severe, acute and long-term clinical outcomes including developmental delay and epilepsy. Neonatal seizures are one of the most common co-morbidities of neonatal encephalopathy with seizures aggravating acute injury and clinical outcomes. Phenobarbital, frontline treatment for neonatal seizures, is, however, ineffective in 50% of infants and may even exacerbate symptoms. Consequently, we must identify safer drug targets which are effective against neonatal seizures. Neuroinflammation is increasingly recognized to contribute to neonatal brain injury and long-lasting changes in brain excitability along with associated cognitive and behavioural deficits. In the brain, ATP also acts as signalling molecule accumulating in the extracellular space under pathological conditions. Once released, ATP activates specific cell membrane receptors including purinergic metabotropic P2Y receptors thereby contributing to inflammation and increased hyperexcitability states. Among these, the P2Y1 subtype has recently attracted much attention as potential novel anticonvulsive and anti-epileptogenic target. Data produced by the applicant has shown P2Y1 to be increased in the brain following acute seizures and during epilepsy, and P2Y1-targeting drugs to reduce seizure severity and the development of epilepsy. To date, however, whether P2Y1 has a role during neonatal brain injury remains to be explored. To establish P2Y1-targeting as a possible novel treatment option for neonatal brain injury and seizures we have identified the following three key challenges:  1) Characterize the expression profile of P2Y1 following neonatal brain injury. 2) Establish the contribution of P2Y1 to neonatal seizures, brain injury and clinical outcomes and, 3) determine P2Y1-specifc downstream signalling following neonatal brain injury. To carry out this research project, the applicant will use genetic and pharmacological approaches in pre-clinical models of neonatal brain injury, human-induced pluripotent stem cells and single-cell sequencing to identify P2Y1 downstream signalling.