Table 1.

Baseline ventilation characteristics

Group	Frequency, breaths per minute	TV, milliliters per breath	MV, mL/min	PIF, mL/sec	PEF, mL/sec	TV/Ti, mL/sec
6 months
Control	239 ± 7	0.27 ± 0.00	64.8 ± 3.7	5.9 ± 0.2	3.4 ± 0.2	3.4 ± 0.2
Gaa−/−	197 ± 6*	0.21 ± 0.00*	41.6 ± 2.3*	3.3 ± 0.2*	2.2 ± 0.1*	1.7 ± 0.1*
12 months
Control	252 ± 7	0.31 ± 0.00	77.3 ± 3.4	6.7 ± 0.2	4.4 ± 0.2	3.9 ± 0.2
Gaa−/−	186 ± 7*	0.23 ± 0.00*	43.2 ± 2.3*	3.6 ± 0.1*	2.3 ± 0.1*	2.1 ± 0.1*
>21 months
Control	225 ± 7†	0.33 ± 0.00†	73.4 ± 3.2	6.3 ± 0.3	4.6 ± 0.2	3.7 ± 0.2
Gaa−/−	168 ± 7*†	0.25 ± 0.01*†	41.8 ± 3.8*	3.5 ± 0.3*	2.3 ± 0.2*	2.1 ± 0.2*

Baseline (21% O₂, balanced N₂) values for frequency, tidal volume (TV), minute ventilation (MV), peak inspiratory flow (PIF), peak expiratory flow (PEF), and tidal volume to inspiratory time ratio (TV/T_i) of control and Gaa^−/− mice.

*Gaa^−/− different from control (P < 0.01).

^†More than 21 months is different from 6 months (P < 0.01). See supplement for n values (Table S3).