Fig. 2.
Co-application of nitrogen gas mixture gas to carbogen gas has no impact on hyperpolarization-activated cyclic nucleotide-gated cation channel-mediated currents (Ih), whereas substitution of nitrogen mixture with xenon gas mixture results in reduced Ih amplitude. (A) Hyperpolarization-activated cyclic nucleotide-gated cation channel-mediated currents (Ih) were obtained by hyperpolarization of neurons to the indicated membrane potentials (voltage protocol not shown). Simultaneous aeration of the artificial cerebrospinal fluid with both carbogen and nitrogen mixture had no effect on Ih amplitude (96.9 ± 21% of carbogen saturation only; at membrane potential of −133 mV). (B) Hyperpolarization-activated cyclic nucleotide-gated cation channel-mediated voltage sag and rebound burst delay were recorded in current clamp configuration. Saturation of the aCSF with carbogen and nitrogen mixture affected neither voltage sag (1.18 ± 0.31 relative to carbogen only; n = 5; P > 0.05) nor rebound delay (0.92 ± 0.20 relative to carbogen only; n = 5; P > 0.05). (C) Slices were perfused with artificial cerebrospinal fluid that was aerated with both carbogen and nitrogen mixture under control conditions, followed by the experimental condition in which nitrogen mixture was replaced by xenon mixture. Substitution of nitrogen mixture with xenon mixture significantly reduced Ih amplitude by 23.2 ± 18.2% compared to Ih amplitude (at membrane potential of −133 mV) in the presence of carbogen + nitrogen mixture (n = 5; P < 0.05). ns = no significant difference (P > 0.05).