Long term exposure to the chemokine CCL2 activates the nigrostriatal dopamine system: a novel mechanism for the control of dopamine release.

Accumulating evidence show that chemokines can modulate the activity of neurons through various mechanisms. Recently, we demonstrated that CCR2, the main receptor for the chemokine CCL2, is constitutively expressed in dopamine neurons in the rat substantia nigra. Here we show that unilateral intranigral injections of CCL2 (50 ng) in freely moving rats increase extracellular concentrations of dopamine and its metabolites and decrease dopamine content in the ipsilateral dorsal striatum.