IUPAC_name = Bicuculline

width = 200
height = 150
CAS_number = 485-49-4
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PubChem = 10237
DrugBank =
smiles = C1=C6C(=CC2=C1CCN( [C@@H] 2 [C@H] 3C4C(C(O3)=O)C5=C(C=C4)OCO5)C)OCO6
C=20 | H=17 | N=1 | O=6
molecular_weight = 367.352 g/mol
bioavailability =
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Bicuculline (BIC) is a light-sensitive competitive antagonist of GABAA receptors. It was originally identified in 1932 in plant alkaloid extracts [Manske, Can. J. Res. 7:265, 1932] and has been isolated from "Dicentra cucullaria", "Adlumia fungosa", "Fumariaceae", and several "Corydalis" species. Since it blocks the inhibitory action of GABA receptors, the action of bicuculline mimics epilepsy. This property is utilised in laboratories across 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 and related anxiolytic drugs.

The half-maximal (IC50) effect of bicuculline on GABAA receptors is 3 μM.

In addition to being a potent GABAA receptor antagonist, bicuculine can be used to block Ca2+-activated potassium channels [Khawaled R, Bruening-Wright A, Adelman JP, Maylie J (1999) Bicuculline block of small-conductance calcium-activated potassium channels. Pflügers Arch 438: 314-321] .

Sensitivity to bicuculline is defined by IUPHAR as a major criterion in the definition of GABAA receptors — however in recent years a new class of ionotropic GABA receptor, defined variously as GABAA or GABAC has been characterised, which is insensitive to both benzodiazepines and bicuculline.

A water soluble form of bicuculline, bicuculline methiodide, is soluble in water to a concentration of 10 mg/mL.


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  • bicuculline — From Dicentra cucullaria and herbs of the genus Corydalis. Specific blocking agent for the action of the amino acid transmitter g aminobutyric acid (GABA). See amino acid transmitter; amino acid receptor superfamily, GABA receptor …   Dictionary of molecular biology

  • bicuculline — noun A light sensitive competitive antagonist of GABA receptors; it is used in the study of epilepsy …   Wiktionary

  • bicuculline — An alkaloid naturally occurring in the d form; found in Dicentra cucullaria and Adlumia fungosa (family Fumariaceae) and several Corydalis species; a powerful convulsant that acts by antagonizing γ aminobutyric acid, an inhibitory… …   Medical dictionary

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