Prostaglandin E2 (PGE2) evokes distinct responses through four different ‘E prostanoid’ (EP) receptors. EP2 is a G protein-coupled receptor that has diverse roles, including those in cancer, inflammation, and neuroprotection. TG4-155 is a brain penetrant EP2 antagonist (KB = 2.4 nM) that is over 1000-fold less effective at EP4 (KB = 11.4 μM) and a panel of other receptors and channels. It blocks the induced expression of inflammatory markers in microglial cells treated with the selective EP2 agonist butaprost alone or with LPS and IFNγ. TG4-155 significantly reduces neurodegeneration in a mouse model of status epilepticus, induced by pilocarpine . It inhibits proliferation, invasion, and inflammatory cytokine expression in cancer cells treated with butaprost.