P2RX7 and Anxiety: Psychological stress induces the release of ATP, activating P2X7 receptors thus leading to depressive behaviours in mice; the anxiety behaviour can be reversed by administration of P2X7 receptor antagonist.194 Genetic deletion of P2X7 receptor is anti-depressive in mice, and increases the efficacy of antidepressant drugs.195 Single nucleotide polymorphisms (SNPs) in A2A and P2X7 receptor genes are linked to neuropsychiatric pathology.