ZD 7288, an HCN channel blocker, attenuates chronic visceral pain in irritable bowel syndrome-like rats

Figure 1 Behavioral evaluation of visceral pain. A: Schematic drawings illustrating the visually based behavioral scale of the abdominal withdrawal reflex (AWR) in response to graded colorectal distension (CRD). AWR scores are 0, 1, 2, 3, and 4; B: AWR scores of control and irritable bowel syndrome (IBS)-like rats; C: Pain thresholds measured by AWR in rats. The AWR threshold indicates CRD intensity when the AWR score is 3. ^aP < 0.05 compared with control rats.