Figure 2. Continuous hypoxia does not lead to an increased RRP.

Mice were exposed to continuous hypoxia to either match the accumulated total time of exposure under CIH (CH–2.5 h) or match the total days of exposure (CH–day 4). Tissue slices were prepared and the RRP was measured by dual-pulse excitation. A, representative examples of capacitance recordings (a) and calcium currents (b) evoked from CH–2.5 h treatment are provided and do not exhibit the enhanced capacitance response or decreased Ca²⁺ influx measured under the CIH–day 4 condition. B, likewise, evoked capacitance jumps (a) and calcium currents (b) under CH–day 4 also failed to display the facilitation measured in the CIH-treated mice. C, data pooled for all conditions (n= 12, 15, 7, 9) showing that only cells taken from mice treated with intermittent hypoxia (CIH–day 4) show a significant difference in the size of the RRP as assayed by dual pulse stimulation (*P < 0.02).