Role of cholecystokinin-B receptor in the maintenance of thermal hyperalgesia induced by unilateral constriction injury to the sciatic nerve in the rat.

To gain a better understanding of the role of cholecystokinin (CCK)-B receptor in the maintenance of thermal hyperalgesia induced by unilateral constriction injury to the sciatic nerve in the rat, this study evaluated the effects of intrathecally administered YM022 (a CCK-B receptor antagonist) on thermal hyperalgesia. Drugs were administered intrathecally 1 or 5 weeks after the nerve injury (1 and 5 week study). In the 5 week study, but not the 1 week study, YM022 attenuated the level of thermal hyperalgesia in a dose-dependent manner. These data indicate that a CCK-B receptor antagonist attenuates the level of thermal hyperalgesia and this effect of a CCK-B receptor antagonist is time-dependent.