Figure 2.

Age-dependent changes in phenotype of response to electrical field stimulation (EFS) in human ascending but not descending colon. For each patient (n=239), a mean of 10 strips (range 3–31) were examined and the number which relaxed or contracted during EFS expressed as the percentage of total tested for that patient. Panel A shows the percent values for relaxation during EFS in ascending colon from all patients. The linear regression line (95% confidence bands as dotted lines) demonstrates an increased likelihood of relaxation as age increases (slope=0.49%±0.21%/ year, n=109). Panel B shows no age-related changes in the percentage values for relaxation during EFS in descending colon (all patients: slope=0.09%±0.17%/year, n=130). Panel C shows the overall percentage of strips relaxing during EFS for each of the tissues studied and the percentage that contract after EFS, placed in the adult (35–60 years old; □) and elderly (≥70 years old; ■) age groups. For ascending colon, n=31 and 58 and for descending colon, n=45 and 46. The data are given as means (±SEM). These were analysed using analysis of variance with Sidak’s multiple comparison tests; *p<0.05. For comparison between adult ascending and descending colon contraction after EFS, p=0.06, all other comparisons between adult groups, and adult and elderly groups were not statistically significant (p>0.70).