Bicuculline is a phthalide-isoquinoline compound that is a light-sensitive competitive antagonist of GABAA receptors.[1] It was originally identified in 1932 in plant alkaloid extracts[2] and has been isolated from Dicentra cucullaria, Adlumia fungosa, and several Corydalis species (all in subfamily Fumarioideae, previously known as family Fumariaceae). Since it blocks the inhibitory action of GABA receptors, the action of bicuculline mimics epilepsy; it also causes convulsions. This property is utilized in laboratories around the world in the in vitro study of epilepsy, generally in hippocampal or cortical neurons in prepared brain slices from rodents. This compound is also routinely used to isolate glutamatergic (excitatory amino acid) receptor function.
The action of bicuculline is primarily on the ionotropic GABAA receptors, which are ligand-gated ion channels concerned chiefly with the passing of chloride ions across the cell membrane, thus promoting an inhibitory influence on the target neuron. These receptors are the major targets for benzodiazepines, z-drugs, and related anxiolytic drugs.
The half-maximal inhibitory concentration (IC50) of bicuculline on GABAA receptors is 3 μM.[citation needed]
In addition to being a potent GABAA receptor antagonist, bicuculline can be used to block Ca2+-activated potassium channels.[3]
Sensitivity to bicuculline is defined by IUPHAR as a major criterion in the definition of GABAA receptors
^Johnston, Graham AR (2013). "Advantages of an antagonist: bicuculline and other GABA antagonists". British Journal of Pharmacology. 169 (2): 328–336. doi:10.1111/bph.12127. ISSN 1476-5381. PMC 3651659. PMID 23425285.
^Manske RH (1932). "The Alkaloids of Fumaraceous Plants. II. Dicentra cucullaria (L.) Bernh". Canadian Journal of Research. 7 (3): 265–269. Bibcode:1932CJRes...7..265M. doi:10.1139/cjr32-078.
Bicuculline is a phthalide-isoquinoline compound that is a light-sensitive competitive antagonist of GABAA receptors. It was originally identified in...
It has long been recognized that, for neurons that are stimulated by bicuculline and picrotoxin, the fast inhibitory response to GABA is due to direct...
used for counteracting overdoses of sedative drugs. Examples include bicuculline, securinine and metrazol, and the benzodiazepine GABAA receptor antagonist...
binding site for GABA and several drugs such as muscimol, gaboxadol, and bicuculline. The protein also contains a number of different allosteric binding sites...
Strychnine is a strong antagonist at ionotropic glycine receptors, whereas bicuculline is a weak one. Glycine is a required co-agonist along with glutamate...
Heinemann U (April 2007). "Effects of the GABA(A) receptor antagonists bicuculline and gabazine on stimulus-induced sharp wave-ripple complexes in adult...
PMID 21833169. Hill DR, Bowery NG (March 1981). "3H-baclofen and 3H-GABA bind to bicuculline-insensitive GABA B sites in rat brain". Nature. 290 (5802): 149–52. Bibcode:1981Natur...
Strychnine is subcategorized as a convulsant along with picrotoxin and bicuculline, though these convulsants inhibit GABA receptors instead of glycine....
interoceptive stimulus produced by ethanol withdrawal is potentiated by bicuculline and picrotoxinin". Neuropsychopharmacology. 2 (2): 115–22. doi:10...