[Effect of ketamine on the excitability of peripheral nerves]

We evaluated the effect of ketamine on the excitability of rabbits vagus nerve by measuring evoked compound action potentials. Histological examination was also done by means of electron microscopy on the nerves incubated in ketamine-Ringer's bicarbonate (RB) solution. We found that 0.05% ketamine causes complete suppression of the compound action potentials. The suppressed compound action potentials by incubating in 0.1% ketamine RB solution recovered completely after washing with ketamine-free RB solution. The electron microscopic examinations revealed no histological changes of the nerves incubated in 0.1% ketamine RB solution. We conclude that ketamine suppresses the nerve excitability causing no histological changes at the concentration below 0.1%.