Arachidonic acid (AA) is released from cells after nervous tissue injuries.We treated rat cortical neurons and astrocytes cultured under normoxic or simulated ischemic conditions with N-acetylcysteine (100 or 200 microM) or ebselen (10 or 20 microM). N-acetylcysteine decreased AA release in normoxic astrocytes, while ebselen decreased AA release from astrocytes in both conditions. N-acetylcysteine produced no changes in neuronal AA release. A low dose of ebselen significantly increased AA release from neurons in both conditions. The influence of N-acetylcysteine and ebselen on AA release might be implicated in their effects on astrocytes and neurons, however, the exact mechanisms have yet to be explained.