Abstract
1. The effects of nitrous oxide and tetrodotoxin were investigated on the reticulospinal inhibitory pathway in the acutely decerebrated cat.2. Both agents abolished the reticular inhibition of the segmental reflex potentials before they blocked either the segmental reflex potentials or the reticular facilitation of the reflex potentials.3. These results confirmed the hypothesis that preferential block of the reticulospinal inhibitory pathway might be an important neural mechanism of the excitement stage of anaesthesia.