Abstract: AIM: To evaluate the effects of atorvastatin on large-conductance calcium-activated potassium channel(BKCa, MaxiK) of arteria mesenterica minor smooth muscle cells in spontaneously hypertensive rats. METHODS: Twelve male spontaneously hypertensive rats(SHR) aged 9 weeks were randomly divided into atorvastatin treatment group(ATV group, n =6) and distilled water group(DW group, n =6), and 6 Wistar-Kyoto rats were as normal control group (n = 6). Atorvastatin and appropriate distilled water were administered to rats in ATV group (50 mg·kg^-1·d^-1) for 10 weeks by intragastric administration. The changes of abdominal aortic blood pressure were observed and the contents of TC, TG, LDL-C in serum were measured before and after treatment. The arterial mesenterica smooth muscle cell potassium current were recorded using whole cell patch clamp. The BKCa membrane capacitance and its current densitys were detected after the BKCa was blocked using tetraethylammonium. RESULTS: The abdominal aorta blood pressure in ATV group was much lower than that in DW group[(171 ±8) mm Hg vs(190 ±10) mm Hg, P < 0.01] (1 mm Hg =0.133 kPa). The BKCa membrane capacitance of arteria mesenterica smoothmuscle cell in ATV group was decreased [(23.8 ±2.6) pF vs (30.0 ±2.5) pF, P <0.01] and the current density was significantly increased[(13.2 ±1.2) pA /pF vs (9.2 ±1.2) pA /pF, P <0.01) compared with that in DW group, but there was no difference compared with that in WKY group. CONCLUSION: Long-term administration of atorvastatin can effectively reduce the blood pressure of SHR. The mechanism probably is the BKCa is activiated by atorvastatin and the angiotasis is adjusted.

Key words: atorvastatin, large-conductance calcium-activated potassium channel, patch clamp technique, hypertension