bicuculline

Bicuculline is a chemical that acts as a competitive antagonist of the gamma-aminobutyric acid type A (GABA_A) receptor in the mammalian central nervous system. By binding to the GABA binding site on the receptor, it prevents GABA from activating the chloride channel, thereby reducing inhibitory synaptic transmission and increasing neuronal excitability.

It is reversible and selective for GABA_A receptors. The blockade of GABAergic inhibition can produce convulsant effects in vivo and epileptiform activity in brain tissue. It is commonly used as a pharmacological tool to study GABAergic signaling, test the function of inhibitory circuits, and examine the balance of excitation and inhibition in neural networks.

Derivative and experimental tools: A widely used derivative is bicuculline methiodide (BMI), a quaternary ammonium salt that is more water-soluble and poorly crosses the blood–brain barrier when administered systemically. BMI is frequently employed in brain-slice experiments or targeted injections to block GABA_A receptors locally.

Safety and handling: Bicuculline is a convulsant and should be handled under appropriate safety procedures in a laboratory setting. It is used only for research purposes and is not approved for any clinical therapy.