Possible therapeutic application of GABAB receptor agonists and antagonists.

After their discovery within the mammalian periphery in 1981, gamma-aminobutyric acid-B (GABAB) receptors have been characterized also in the central nervous system (CNS). The highest concentrations of GABAB binding sites appear to be in the cerebellum, frontal cortex, and thalamic nuclei, where they are located on pre- and postsynaptic neurons. On activation, the primary effects appear to be membrane hyperpolarization, suppression of transmitter release, and changes in the levels of cyclic nucleotides. GABAB receptors have been implicated in a variety of neurological phenomena and, as a consequence, receptor agonists and antagonists may well have therapeutic potential. This article is an introduction to GABAB receptor pharmacology and reviews the future of the receptor ligands. Particular attention is given to the role of spinal cord GABAB receptors in chronic pain.