Phosphorylation of Extracellular Signal-Regulated Kinase1/2 and Caldesmon in Rat Colon by Electrical Stimulation to Sacral Plexus Following Spinal Cord Injury

ABSTRACT

OBJECTIVE: To find out whether electrical stimulation affects intracellular signaling mechanisms that link the biochemical and mechanical events of smooth muscle contraction. METHOD: A total of 31 adult Sprague-Dawley female rats were divided into 3 groups control group, spinal cord injury (SCI) only group, and spinal cord injury with electrical stimulation (SCI+ES) group. Complete spinal cord transection was performed surgically at T10 cord level. The electrode for electrical stimulation was implanted into sacral spinal cord region (S2-4). Electrical stimulation was applied 4 hours per day from the day of operation. RESULTS: In SCI+ES group, the weights of fecal pellet were significantly higher from the 3rd day of post-operation to the 6th day than the SCI only group. The numbers of pERK 1/2 immunoreactive cells significantly increased in all colon segments of the SCI+ES group but had decreased in the SCI only group. Western blot showed the stronger bands of phosphorylated ERK1/2 in all colon segments and also phosphorylated caldesmon in mid or distal colon segments in the SCI+ES group. CONCLUSION: These results suggest that electrical stimulation to sacral plexus region activate phosphorylation of ERK1/2 and caldesmon which leads to improvement of bowel function by promotion of secretion or motility in the colon.