Table 1.

Hypoxic ventilatory responses in rats pretreated with artificial CSF, methysergide, emetine (1 μg/kg), or cycloheximide

Amplitude change in hypoxia (% above baseline)Burst frequency (bursts/min)
∫Phr∫XIIBaselineHypoxia
Artificial CSF111  ± 161-a137  ± 281-a36.2  ± 1.344.5  ± 1.31-a
Methysergide88  ± 101-a119  ± 181-a44.3  ± 1.61-b48  ± 2
Emetine172  ± 491-a155  ± 141-a40.2  ± 1.745.8  ± 1.81-a
Cycloheximide89  ± 131-a199  ± 451-a40.7  ± 2.449.4  ± 2.71-a
  • All rat groups significantly increased integrated phrenic (∫Phr) and hypoglossal (∫XII) amplitude (percentage above baseline) similarly during hypoxia (p > 0.05). Rats pretreated with artificial CSF, emetine, or cycloheximide had a significant increase in burst frequency in hypoxia (p < 0.05). Rats pretreated with methysergide had a significantly elevated baseline frequency (p < 0.05) but did not have a significant increase in burst frequency during hypoxia (p > 0.05).

  • F1-a Significantly different from baseline.

  • F1-b Significantly different from artificial CSF control.