Effects of long-term treatment with dopamine receptor agonists and antagonists on terminal arbor size

Abstract

This study demonstrates that pharmacological manipulation of the dopamine (DA) receptors can modulate the size of the axonal tree of substantia nigra pars compacta (SNpc) neurons in mice. Pharmacological blockade or genetic ablation of the D2 receptor (D2R) resulted in sprouting of DA SNpc neurons whereas treatment with a D2 agonist resulted in pruning of the terminal arbor of these neurons. Agents such as cocaine, that indirectly stimulate D2R, also resulted in reduced terminal arbor. Specific D1 agonists or antagonists had no effect on the density of DA terminals in the striatum. We conclude that the D2 receptor has a central role in regulating the size of the terminal arbor of nigrostriat..