Dopamine

Dopamine exerts slow inhibitory actions at synapses in specific neuronal systems, commonly via G protein-coupled activation of potassium channels (postsynaptic) or inhibition of calcium channels (presynaptic). The D2 receptor is the main dopamine subtype in basal ganglia neurons, and it is widely distributed at the supraspinal level. Dopaminergic pathways include the nigrostriatal,  mesolimbic, and tuberoinfundibular tracts.