Abstract: AIM:To investigate the effect of valsartan, ramipril and anlodipine on the expression of TRPC3 and TRPC6 in the left ventricle in spontaneously hypertensive rats (SHR). METHODS: Twelve-week-old SHRs were randomly divided into four groups: valsartan-treated group (Val), ramipril-treated group (Ram), amlodipine-treated group (Aml) and untreated group (SHR). Twelve-week-old Wistar-Kyoto (WKY) rats were used as control group. After 4 weeks of drug intervention, blood pressure (BP), left ventricular mass index (LVMI), left ventricular cardiomyocytes transection diameter (LVTDM) were examined, RT-PCR and Western blotting were used to detect the expressions of TRPC3 and TRPC6 mRNA and protein. RESULTS: Compared with those in WKY, BP, LVMI and LVTDM in SHR were significantly higher (P<0.05) and the data mentioned above decreased significantly in the drug intervention groups (P<0.05). Expressions of TRPC3 and TRPC6 mRNA and protein were detected in each group and were significantly higher compared with those in WKY. TRPC3 decreased dramatically in drug intervention groups (P<0.05) and TRPC3 mRNA and protein decreased significantly in Val group compared with those in Ram group and Aml group. TRPC6 mRNA and protein expressions decreased in drug intervention groups; however, no significant changes in TRPC6 mRNA and protein expressions were observed. CONCLUSION: Expressions of TRPC3 and TRPC6 were found in SHR and WKY. TRPC3 and TRPC6 may co-regulate the pathphysiological processes of myocardial hypertrophy. Valsartan may inhibit left ventricular hypertrophy, probably by downregulating mRNA and protein expression of TRPC3.