Whole-body plethysmography

Unrestrained Mecp2^+/− and Mecp2^+/+ mice were placed in a WBP recording chamber (Buxco, two-site system) with a continuous inflow of air (1 liter/min). After a habituation period of 45 min, a baseline recording was established for 30 min. Mice were then removed from the chamber, injected intraperitoneally with compound, and reaccli-mated for 30 min, and respirator measurements were made for an additional 30 min. Analysis was performed using FinePointe Research Suite (version 2.3.1.9). Apneas, defined as pauses spanning twice the average expiratory time of the previous 2 min, were quantified using the FinePointe apnea software patch, followed by manual spot checking of the larger data set. Only points of motion-free recording were analyzed. Periods of movement were removed (i) automatically by the FinePointe apnea software, (ii) manually by identifying points where the Δ-chamber volume exceeded the normal breath range, and (iii) at points where the researcher present during the recording noted activity. All filters were applied while the researchers were blinded to genotype and treatment group.