Downregulation of Kir6.1/SUR2B channels in the obese rat aorta.

This study was designed to evaluate the contribution of adenosine triphosphate-dependent potassium channels to the increase in blood pressure observed in obese rats.The experiment was performed in male Sprague-Dawley rats. Glibenclamide-sensitive currents were measured in vascular smooth muscle cells by patch-clamp. Expressions of Kir6.1 and SUR2B were examined by reverse transcription polymerase chain reaction and western blot techniques, respectively.In the aortic vascular smooth muscle cells, pinacidil induced glibenclamide-sensitive currents. The current from obese rats was significantly lower (-10.55 +/- 1.63 pA/pF) compared with that from the control rats (-20.18 +/- 2.79 pA/pF). Expressions of Kir6.1 and SUR2B were downregulated in vascular smooth muscle cells of aortas from the obese rats.These findings suggest that the adenosine triphosphate-dependent potassium channel is downregulated in smooth muscle cells from the aortas of obese rats, which may contribute to the increase in blood pressure in these rats.