Table 1. Respiratory pattern and apnea in Ndn−/− young adult versus Ndn+m/−p mice.

	Ndn+m/−p	Ndn−/−
Animal weight (g)	16.7±2.3	16.4±2.7
Minute Ventilation (ml.min−1.g−1)	2.0±0.6	2.6±1.0
Breathing Frequency (BPM)	256.7±56.6	298.3±81.4
Tidal Volume (ml.10−3.g−1)	7.9±1.0	8.7±1.8
Expired Volume (ml.10−3.g−1)	7.8±1.0	8.7±1.8
Expiratory Time (ms)	174.9±28. 9	166.3±45.0
Apnea number, per hour	8.8±8.9	18.2±14.4a
Apnea duration (ms)	900±109	929±107
% of animals with apnea >750 ms	89%	84%
Apnea scores (% time.hour−1)	0.2±0.2	0.5±0.4b

While the mean apnea duration was similar between genotypes (∼900 msec), evaluation of the total apnea duration expressed as the total recording time (i.e. apnea scores) revealed a two-fold increase in the percentage of total apnea duration in Ndn−/− compared to Ndn+m/−p individuals.

Values are represented as Mean±SD; n = 20 for Ndn+m/−p and 18 for Ndn −/− mice.

Mann Whitney t-test, two-tailed. P value = 0.02 (a) and 0.03 (b).