P2 receptor activation injures cortical neurons in vitro. Cocultures of rat cortical neurons and microglia were incubated for 3 days   100  M -O -(4-benzoyl-benzoyl)ATP (BzATP)   3 M Brilliant Blue G (Blue G). Labeling for the neuron-specific marker III-tubulin showed neurons to survive well and elaborate extensive neurite networks in cultures with unstimulated microglia (a), whereas BzATP caused a drastic and neuron-selective degeneration (b) that the P2 receptor antagonist Brilliant Blue G (c) prevented. Reproduced from Skaper et al. [57], with permission from Wiley-Liss, Inc.