PT  - JOURNAL ARTICLE
AU  - N. G. Bowery
AU  - B. Bettler
AU  - W. Froestl
AU  - J. P. Gallagher
AU  - F. Marshall
AU  - M. Raiteri
AU  - T. I. Bonner
AU  - S. J. Enna
TI  - International Union of Pharmacology. XXXIII. Mammalian γ-Aminobutyric Acid<sub>B</sub> Receptors: Structure and Function
AID  - 10.1124/pr.54.2.247
DP  - 2002 Jun 01
TA  - Pharmacological Reviews
PG  - 247--264
VI  - 54
IP  - 2
4099  - http://pharmrev.aspetjournals.org/content/54/2/247.short
4100  - http://pharmrev.aspetjournals.org/content/54/2/247.full
SO  - Pharmacol Rev2002 Jun 01; 54
AB  - The γ-aminobutyric acidB(GABAB) receptor was first demonstrated on presynaptic terminals where it serves as an autoreceptor and also as a heteroreceptor to influence transmitter release by suppressing neuronal Ca2+ conductance. Subsequent studies showed the presence of the receptor on postsynaptic neurones where activation produces an increase in membrane K+ conductance and associated neuronal hyperpolarization. (−)-Baclofen is a highly selective agonist for GABAB receptors, whereas the established GABAAreceptor antagonists, bicuculline and picrotoxin, do not block GABAB receptors. The receptor is Gi/Go protein-coupled with mixed effects on adenylate cyclase activity. The receptor comprises a heterodimer with similar subunits currently designated 1 and 2. These subunits are coupled via coiled-coil domains at their C termini. The evidence for splice variants is critically reviewed. Thus far, no unique pharmacological or functional properties have been assigned to either subunit or the variants. The emergence of high-affinity antagonists for GABAB receptors has enabled a synaptic role to be established. However, the antagonists have generally failed to establish the existence of pharmacologically distinct receptor types within the GABAB receptor class. The advent of GABAB1 knockout mice has also failed to provide support for multiple receptor types.