Objective: To explore the role of phosphorylation of cAMP response element binding protein (CREB) in the incision-induced pain hypersensitivity.
Methods: A longitudinal incision was made in one plantar hind paw of isoflurane-anesthetized rats. Spinal cords were removed at various postoperative time after behavior test. Phosphorylation of CREB was determined by immunohistochemistry and double-labeling immunofluorescence. Morphine and gabapentin were intraperitoneally injected before the behavior test and were used to determine the interaction between phosphorylation of CREB and morphine and gabapentin.
Results: After the hind-paw incision, phosphorylation of CREB was enhanced in the ipsilateral lumbar spinal cord (P<0.05). The enhancement of p-CREB was mainly in the neurons in the dorsal horn of the spinal cord. All these were shown by double-labeling technique and p-CREB was mainly in the neurons. Intraperitoneal injection of morphine prevented the increased phosphorylation of CREB in the spinal cord and inhibited the mechanical allodynia induced by the incision (P>0.05). Gabapentin didn't inhibit the phosphorylation of CREB (P<0.05) but partly inhibited the mechanical allodynia.
Conclusion: Incision induces the phosphorylation of CREB in the spinal cord, and the increase of p-CREB is mainly in the neurons. Phosphorylation of CREB in the spinal cord contributes to the pain hypersensitivity induced by surgical incision.