Fig. 8.

Effect of chronic stress on distal colonic contractions in conscious mice. A miniature pressure transducer catheter was placed in the distal colon of mice (2 cm proximal to the anus) under brief isoflurane anesthesia. CRF-overexpressing (OE) mice (n = 10), a genetic model of chronic stress or control (wild-type littermates and C57Bl/6) mice submitted to 15 consecutive sessions of partial restraint stress (60 min/day, for 15 days, colon contractions monitored on the 15th day, n = 6) or control mice (no prior stress, n = 12) were placed in the partial restraint stress tube and distal colonic contractions recorded. A: representative raw trace of distal colon in mice submitted to a single acute stress (top), mice submitted to chronic stress [15 consecutive sessions of acute partial restraint stress (60 min·h⁻¹·day⁻¹) (middle), and CRF-OE mice (bottom)]. B: time course (during 60 min) AUC of the distal colon in the acute vs. the chronic stress groups. C: AUC of distal colonic at different time intervals during the 60-min recording period. D: frequency of contractions as a function of amplitude or duration of contractions. *P < 0.05 vs. the corresponding 0- to 10-min time period, #P < 0.05 vs. the corresponding acute stress; ANOVA.