The aim of this study was to find out, whether P2X7 receptors are present on cortical astrocytes of the rat and mouse brain, possibly participating in neuron-glia interaction or neurodegenerative processes. Primary cell cultures and slice preparations of the rat cerebral cortex were used for immunohistochemistry and whole-cell patch clamp experiments. In primary cultures of the rat cerebral cortex, astrocytes reacted to the application of ATP or dibenzoyl-ATP (Bz-ATP) with inward currents at a holding potential of -80 mV. These current responses considerably increased in an external medium containing no Mg²⁺ and low Ca²⁺ concentrations. The use of various receptor-type selective agonists and antagonists suggested the presence of P2X7 receptors. In brain slices of the rat prefrontal cortex, astrocytes were identified on the basis of their small cell diameters, and the absence of action potentials induced by depolarizing current injection. Immunohistochemistry experiments revealed that astrocytes labelled after recording with pipettes filled with the fluorescent dye Lucifer Yellow (LY), exhibited co-localization of LY with immunoreactivity for GFAP and P2X7 receptors. Once again, all astrocytes reacted to ATP and BzATP at a holding potential of -80 mV with inward current. The current responses to ATP and BzATP were greatly potentiated in a divalent cation-poor medium. Both the agonist and antagonist profiles of the P2 receptor-ligands investigated suggested the existence of P2X7 receptors. Hence, rodent astrocytes appeared to exhibit P2X7 receptors together with a range of P2Y receptor-types. These receptors may be involved in immunological defence reactions, apoptosis/necrosis as well as long-term proliferation such as gliosis.