GABAB receptors - Role and therapeutic implications in CNS disorders

The neurotransmitter gamma-aminobutyric acid (GABA) activates more than one receptor subtype, including the metabotropic receptor, GABA(B). GABA(B) receptors are located at pre- and postsynaptic sites on central neurons and mediate changes in the membrane conductance of potassium and calcium ions. This influences transmitter release as well as affecting neuronal activity directly. The GABA(B) system can be modified by receptor ligands. This is currently exploited clinically, within the spinal cord, with the use of the GABA(B) agonist baclofen to treat spasticity and, to a lesser degree, trigeminal neuralgia. However, other potential uses of GABA(B) ligands may be on the horizon in relation to absence epilepsy, cognitive impairment and depression.