Table 1.

Ventilation and sigh responses to hypoxia or hypercapnia

	V̇e, ml/min	f, breaths/min	Vt, ml	No. of sighs	Amplitude of sighs, ml
Hypoxia	485±24	127±3	3.84±0.45	4.75±0.57	9.45±0.48
Hypercapnia	674±47†	130±6	5.16±0.38†	3.43±0.32*	8.66±0.85

Values are means ± SE; n = 6 rats. V̇e, minute ventilatory volume; f, respiratory frequency; Vt, tidal volume. All data were averaged from 3 degrees of 1.5-min hypoxia (15%, 10%, and 5% O₂) and 4-min hypercapnia (3%, 7%, and 10% CO₂).

^*P < 0.05,

^†P < 0.01 compared between hypoxia and hypercapnia.