On the neuronal circuitries and neurotransmitters involved in the control of locomotor activity.
Research on the role of dopamine and other neurotransmitters in the control of motor functions has made considerable progress in recent years. The neuronal circuitries involving especially the basal ganglia have been extensively explored, and evidence has been presented that dopamine does not play a quite as dominant role for the initiation of movement as was formerly believed. Among several other neurotransmitters involved, special attention has recently been directed to glutamate, which seems to be able to stimulate as well as inhibit motility via different pathways. However, powerful interactions involving other neurotransmitters as well, have been discovered. Another area of intensive research deals with the role of the different subtypes of dopamine receptors. Whereas D-1 and D-2 receptors cooperate in the initiation of movement, evidence is emerging that they serve partly differential functions and interact differently with, for example, glutamatergic mechanisms. Moreover, the possible role of the various newly discovered dopamine receptor subtypes is being intensively explored.