Relationship between intrathecal baclofen and the central nervous system.

The GABA(B) receptor agonists display a number of pharmacological effects including central muscle relaxation, decreased self-administration of cocaine and narcotic drugs, antinociception, cognitive impairment as well as enhancement of synaptic plasticity. The main relationships between intrathecal or intracerebral baclofen and the Central Nervous System (CNS) are reviewed with particular attention to actions on pain, epilepsy and basal ganglia regulation. Since baclofen may be involved in synaptic plasticity and the development of neuronal pathways, the main issues of this field are reviewed with particular attention to the effects of baclofen on the developing brain. The role of baclofen in the regulation of movement has not been clearly understood, but recent findings support its important involvement in globus pallidus and subthalamic nucleus. The neuroprotective action of baclofen in cerebral ischemia is a matter of debate. The effects of baclofen in cognition and attention are another important issue because patients with chronic intrathecal baclofen (ITB) administration often present with impairment of cognitive functions. Drug craving and its improvement after baclofen administration is also reviewed. Finally, the clinically interesting results on the regulation of food intake and blood pressure are highlighted. The preliminary experience on the effects in cortical neuron viability at different concentrations of ITB is reported.