Serotonin and Central Mechanisms Underlying Motor Control

The review considers in a historical aspect the published data on the role of serotonin in brain activity, as well as on the structure and organization of neuronal projections of serotonergic nuclei. In addition, information on the facilitatory and inhibitory effects of serotonin on neurons of various brain regions under both in vivo and in vitro conditions is presented. General characteristics of the main types of central serotonin receptors are also given. It is emphasized that such receptors form a heterogeneous group, and this is the reason for the diversity of the effects when agonists and antagonists are applied. Regularities characteristic of changes in the activity of serotonergic system over the sleep-wakefulness cycle are also analyzed in this review; data on the involvement of serotonin in motor control are cited. Possible reasons for the complexity and multiplicity of the effects evoked by serotonin at different levels of the CNS and within various neuronal structures in the course of motor behavior are discussed.