Functional significance of the negative-feedback regulation of ATP release via pannexin-1 hemichannels under ischemic stress in astrocytes

▶ The suppression of P2X7 receptors during ischemia opened pannexin-1 hemichannels. The opening of hemichannels enhanced the release of ATP. The enhanced ATP release was reversed by co-treatment with pannexin-1 blockers. ATP, released via pannexin-1 hemichannels, activated P2X7 receptors. The activation of P2X7 in turn closed hemichannels during ischemia.