Cocculus - General Information:
A noncompetitive antagonist at GABA-A receptors and thus a convulsant. Cocculus blocks the gamma-aminobutyric acid-activated chloride ionophore. Although it is most often used as a research tool, it has been used as a CNS stimulant and an antidote in poisoning by CNS depressants, especially the barbiturates. [PubChem]
Other Brand Names containing Picrotoxin
Cocculus - Pharmacology:
Cocculus antagonizes the GABAA receptor channel directly, which is a ligand-gated ion channel concerned chiefly with the passing of chloride ions across the cell membrane. Therefore picrotoxin prevents Cl- channel permeability and thus promtes an inhibitory influence on the target neuron. Cocculus reduces conductance through the channel by reducing not only the opening frequency but also the mean open time. Cocculus also antagonizes GABAC receptors (also called GABAA-rho receptors) but the result of this action is not known. The GABAC receptor is also linked to chloride channels, with distinct physiological and pharmacological properties. In contrast to the fast and transient responses elicited from GABAA receptors, GABAC receptors mediate slow and sustained responses.