Fig. 5.
Effects of isoflurane on hippocampal action potentials. (A) The effects of isoflurane at a clinically relevant concentration (0.48 mM, ~1.8 minimum alveolar concentration [MAC]) on single action potentials. (B) Action potential amplitude was reduced and width increased by isoflurane (n = 13, P = 0.001), as illustrated by the action potential dynamics of voltage-time derivative (C). (D and E) Isoflurane significantly reduced action potential frequency (n = 20). (F) Isoflurane significantly hyperpolarized pyramidal neuron resting membrane potential (n = 16, P = 0.001). (G) Isoflurane significantly increased the rheobase that evoked action potentials (n = 14, P = 0.019). (H) Isoflurane significantly increased the input resistant of neurons (n = 12, P < 0.0001). Data are mean ± SD. *P < 0.05, **P < 0.01 by two-tailed paired t test (b, g, h) or two-way ANOVA (E). CTL, control; ISO, isoflurane.