Figure 1.
Intestinal smooth muscle contractile response to CCh. Addition of CCh dose-dependently enhanced contractility in both the (A and B) jejunum (n = 13[4] young; n = 24[7] old) and the (C and D) colon (n = 14[4] young; n = 26[8] old). A dose–response curve is shown on the left and maximum contractility is shown on the right. In the jejunum, there was no significant difference between old vs young baboons. However, there was a significant decrease in overall response to CCh in the old colonic smooth muscle when compared to young. Activation of cholinergic mechanisms by CCh revealed no significant differences in maximal jejunal contractile responses observed in the presence of 6 × 10−6 M CCh. However, there was a significant decline in contractile responses in the old colonic smooth muscle tissue in comparison to young. *p < 0.05, **p < 0.01 significance was determined using two-way repeated measures anova followed by Bonferonni posttest or Student's unpaired t-test for analysis of maximum contractility.