Effects of DA-9701, a Novel Prokinetic Agent, on Phosphorylated Extracellular Signal-Regulated Kinase Expression in the Dorsal Root Ganglion and Spinal Cord Induced by Colorectal Distension in Rats

Abstract

Background/Aims: DA-9701, a standardized extract ofPharbitis Semen and Corydalis Tuber, is a new prokineticagent that exhibits an analgesic effect on the abdomen. Weinvestigated whether DA-9701 affects visceral pain inducedby colorectal distension (CRD) in rats.Methods: A total of21 rats were divided into three groups: group A (no CRD+nodrug), group B (CRD+no drug), and group C (CRD+DA-9701). Expression of pain-related factors, substance P (SP), c-fos,and phosphorylated extracellular signal-regulated kinase (p-ERK) in the dorsal root ganglion (DRG) and spinal cord wasdetermined by immunohistochemical staining and Westernblotting.Results: The proportions of neurons in the DRGand spinal cord expressing SP, c-fos, and p-ERK were higherin group B than in group A. In the group C, the proportion ofneurons in the DRG and spinal cord expressing p-ERK waslower than that in group B. Western blot results for p-ERK inthe spinal cord indicated a higher level of expression in groupB than in group A and a lower level of expression in group Cthan in group B.Conclusions: DA-9701 may decrease visceralpain via the downregulation of p-ERK in the DRG andspinal cord.