Background: Strong evidence supports the concept that conventional anesthetics, including inhalational agents and inert gases, such as xenon and nitrous oxide, interact directly with ion channel neurotransmitter receptors. However, there is no evidence that nitrogen, which only exhibits narcotic potency at increased pressure, may act by a similar mechanism. Methods: We compared the inhibitory and sedative effects of ␥-aminobutyric acid (GABA) and nitrogen pressure on locomotor activity and striatal dopamine release in freely moving rats and investigated the pharmacologic properties of the GABAinduced and nitrogen pressure-induced narcotic action using the highly selective competitive GABA A receptor antagonist bicuculline. Results: Intracerebroventricular GABA infusion up to 60 mol or exposure to nitrogen pressure up to 3 MPa decreased to a similar extent striatal dopamine release (
