ObjectiveTo determine the role of different molecular compositions of K_ATP channels in reducing the blood pressure variability (BPV) in conscious,freely-moving sinoaortic denervated (SAD) rats. MethodsSAD rat model was established. Computerized analytic system of blood pressure was used to observe the effects of unselective K_ATP openers (pinacidil) or Kir6.1/Sur2B and Kir6.1/Sur1 selective opener (diazoxide) on BPV of SAD rats. We also observed the effects of pinacidil and diazoxide on BPV of SAD rats pre-treated with selective Kir6.1/Sur1 antagonist 5-hydroxydecanoic acid (5-HD) and selective Kir6.2/Sur2A antagonist (HMR1098). ResultsBoth pinacidil and diazoxide significantly decreased BPV in SAD rats (P<0.01), and pre-treatment with 5-HD+HMR1098 did not change the effect of either pinacidil or diazoxide on BPV of SAD rats. ConclusionOpening Kir6.1/SUR2B of vascular smooth cells can decrease the BPV levels in SAD rats.