Differential expression of TRPC channels in the left ventricle of spontaneously hypertensive rats

This study was designed to identify the differential expression of the canonical transient receptor potential (TRPC) channels in the left ventricle of spontaneously hypertensive rats (SHR). Echocardiography studies were performed to compare the left ventricular function in SHR vs. Wistar-Kyoto rats (WKY), and the mRNA level of the TRPC channels was determined by quantitative real-time RT-PCR (qRT-PCR). Western blots were performed to examine whether the mRNA expression corresponded with the protein expression. Compared with the WKY, the mRNA expression of TRPC4 and TRPC5 was significantly increased in the 10-week-old SHR (P = 0.032 for TRPC4 and P = 0.043 for TRPC5), so did the TRPC4/5 protein content. The midwall fractional shortening (mFS) of SHR was lower than WKY (P = 0.016). Furthermore, increased expression of TRPC4/5 was correlated with both increased blood pressure and decreased mFS. These findings suggest that TRPC4 and 5 seem to be the main subtypes expressed in the heart of the SHR at the beginning period of hypertension. Theses channels may participate in the development of left ventricular systolic dysfunction.