As a lipid-soluble molecule, nitrous oxide enters the brain rapidly to alter the flow of information along a multitude of neuronal pathways and synapses by interfering with membrane ion channels and the action of key neurotransmitters. Some neurotransmitters, such as dopamine and the endogenous opioid peptides, act through G-protein coupled receptors mainly to adjust or modulate synaptic strength, whereas GABA and glutamate are amino acids known for their strong inhibitory or excitatory synaptic effects. Thus, nitrous oxide and nitric oxide belong to what now is becoming a sizeable group of...