The association of cholecystokinin-A receptor expression with the responsiveness of electroacupuncture analgesic effects in rat.

The purpose of this study is to determine whether the level of cholecystokinin (CCK) receptor expression causes the differences between the responder and non-responder to electroacupuncture mediated analgesic effects. Male Sprague-Dawley rats were stimulated at the Zusanli (ST36) acupoint in the absence of any anesthetics and holders. The tail flick latency test was performed to quantify analgesic effects and then the responder and non-responder groups were classified. The hypothalamus of each group was dissected and RNA was purified. The amount of mRNA expression of CCK-A and CCK-B receptors was determined by reverse transcription-polymerase chain reaction. The results show that CCK-A receptors are significantly more expressed in non-responders than responders, whereas CCK-B receptor expression is similar in both groups.