Involvement of TRPV1 in the expression and release of calcitonin gene-related peptide induced by rutaecarpine

Abstract

The traditional Chinese herb Wu-Chu-Yu has been used to treat hypertension for hundreds of years. A previous study indicated that rutaecarpine was the effective component of Wu-Chu-Yu, which lowered blood pressure by elevating the expression level of calcitonin gene-related peptide (CGRP). The present-study was performed to investigate the role of transient receptor potential cation channel subfamily V member 1 (TRPV1) in CGRP expression and release induced by rutaecarpine. Dorsal root ganglia (DRG) obtained from Sprague-Dawley rats were cultured to analyze the mRNA expression and release of CGRP. Calcium influx, as an indicator of TRPV1 activation, was measured in 293 cells with stable overexpression of TRPV1. The results demonstrated that the amount of CGRP in the cell culture supernatant and the mRNA expression of CGRPα and CGRPβ in DRG was upregulated by rutaecarpine in a concentration-dependent manner, and was inhibited by the TRPV1 receptor antagonist capsazepine. In addition, intracellular Ca2+ levels were increased by Rut in the aforementioned 293 cell line, indicating the activation of TRPV1 by Rut. Therefore, it was concluded that TRPV1 was involved in the expression and release of CGRP stimulated by rutaecarpine, which provided novel mechanistic understanding of the treatment of hypertension using the Chinese herb Wu-Chu-Yu.