GABAB receptors can also reduce the activity of adenylyl cyclase and decrease the cell’s conductance to Ca2+.[2]
GABAB receptors are involved in behavioral actions of ethanol, [3]gamma-Hydroxybutyric acid (GHB),[4] and possibly in pain.[5] Recent research suggests that these receptors may play an important developmental role. [6]
Structure
GABABRs are similar in structure to and in the same receptor family with metabotropic glutamate receptors.[7] There are two subtypes of the receptor, GABAB1 and GABAB2,[8][2] and these appear to assemble as heterodimers in neuronal membranes by linking up by their intracellular C termini.[2][7]
It is speculated that binding of GABA causes the subunits to swing shut around the agonist like a venus fly trap.[2]
Agonists and antagonists
Baclofen is a GABA analogue which acts as a selective agonist of GABAB receptors, and is used as a muscle relaxant. However, it can aggravate absence seizures, and so is not used in epilepsy.
Saclofen, phaclofen and SCH-50911 are selective GABAB antagonists.
^ Chen K, Li H, Ye N, Zhang J, Wang J (2005). "Role of GABAB receptors in GABA and baclofen-induced inhibition of adult rat cerebellar interpositus nucleus neurons in vitro". Brain Res Bull67 (4): 310-8. PMID 16182939.
^ abcde Martin I.L., and Dunn S.M.J. 2002. GABA receptors Tocris Cookson Ltd.
^ Dzitoyeva S, Dimitrijevic N, Manev H (2003). "Gamma-aminobutyric acid B receptor 1 mediates behavior-impairing actions of alcohol in Drosophila: adult RNA interference and pharmacological evidence". Proc Natl Acad Sci U S A100 (9): 5485-90. PMID 12692303.
^ Dimitrijevic N, Dzitoyeva S, Satta R, Imbesi M, Yildiz S, Manev H (2005). "Drosophila GABA(B) receptors are involved in behavioral effects of gamma-hydroxybutyric acid (GHB)". Eur J Pharmacol519 (3): 246-52. PMID 16129424.
^ Manev H, Dimitrijevic N (2004). "Drosophila model for in vivo pharmacological analgesia research". Eur J Pharmacol491 (2-3): 207-8. PMID 15140638.
^ Dzitoyeva S, Gutnov A, Imbesi M, Dimitrijevic N, Manev H (2005). "Developmental role of GABAB(1) receptors in Drosophila". Brain Res Dev Brain Res158 (1-2): 111-4. PMID 16054235.
^ ab MRC (Medical Research Counsil). 2003. Glutamate receptors: Structures and functions. University of Brisotol Centre for Synaptic Plasticity.
^ Purves D., Augustine G.J., Fitzpatrick D., Katz L.C., LaMantia A.S., McNamara J.O., and Williams S.M. 2001. Neuroscience, Second Edition. Sinauer Associates, Inc.