British journal of anaesthesia
-
Although N(2)O has been widely used as an anaesthetic adjuvant its effect on electroencephalographic (EEG) activity is poorly understood because it is usually studied in the presence of additional anaesthetics, including inhaled anaesthetics. We examined the EEG effects of N(2)O in rats using a hyperbaric chamber that permitted N(2)O to be the sole anaesthetic. ⋯ These data indicate that N(2)O at peri-MAC partial pressures prevents EEG activation resulting from noxious electrical stimulation. Unlike the situation with isoflurane, stimulus-evoked EEG activation did not occur at peri-MAC anaesthetic concentrations, suggesting that N(2)O potently blocked ascending nociceptive transmission.