FIGURE 7.
Effect of COX-2 inhibitor NS-398 on smooth muscle contractile response to cholinergic activation in Crohn’s-like colitis rats. NS-398 (5 mg/kg, i. p. daily) and vehicle control (DMSO saline) were administered daily to sham and TNBS-induced Crohn’s-like colitis rats. With vehicle treatment, TNBS colitis rats demonstrated a significantly lower colonic smooth muscle contractility than in sham rats in response to all ACh concentrations at both P and I sites (A,a) and (A,b), respectively. With NS-398 treatment, colonic smooth muscle contractility in TNBS colitis rats was not significantly different from sham at the P-site for all ACh concentrations (A–A). Smooth muscle contractility at the I-site was not significantly different between sham and TNBS colitis rats for all ACh concentrations, except that of ACh 10−2 M (A,B). Representative traces for all groups are shown in (B). The signs of “↓” indicate the addition of ACh 10−7 M, 10−6 M, 10−5 M, 10−4 M, 10−3 M, and 10−2 M, respectively from left to right. The number at the right bottom of each trace is the tissue weight of the muscle strip. The vertical and horizontal bars of the insert at the right bottom of panel B indicate 6 g of tension and 2 min of time, respectively for all traces. N = 4 or 5 rats. *p < 0.05 vs. sham/veh. #p < 0.05 vs. sham/NS-398. S, sham; T, TNBS treated rats (Crohn’s-like colitis); Veh, vehicle.