Modulation of imidazoline I2 binding sites by CR4056 relieves postoperative hyperalgesia in male and female rats.

Background And Purpose: CR4056 is a novel imidazoline-2 (I2 ) ligand exhibiting potent analgesic activity in animal models of pain. In this study, we investigated the effects of CR4056 in a well-established model of postoperative pain where rats develop hyperalgesia in the injured hind paw.

Experimental Approach: By measuring paw withdrawal threshold to mechanical pressure, we studied the pharmacology of CR4056, potential sex differences in pain perception and response to treatment, and the pharmacodynamic interaction of CR4056 with morphine.