Dopamine in neurotoxicity and neuroprotection: what do D2 receptors have to do with it?

Accurate control of dopamine levels and/or the resulting dopamine–receptor interaction is essential for brain function. Indeed, several human neurological and psychiatric disorders are characterized by dysfunctions of the dopaminergic system. Dopamine has been reported to exert either protective or toxic effects on neurons, yet it is unclear whether these effects are receptor-dependent and, if so, which dopamine receptor could be involved. The D2 dopamine receptor occupies a privileged position because its signalling might be neuroprotective in human diseases, such as Parkinson's disease, ischaemia and epilepsy. Unravelling the role of D2 receptors in neuronal death and survival might be central to understanding the mechanisms that underlie several neuropathologies.