ABSTRACT
Objective To investigate the changes of membrane potential of mesenteric arteriolar smooth muscle cells (ASMCs) and large conductance calcium-activated potassium channel (BK Ca ) following hemorrhagic shock in rats. Methods (1) The Wistar rats were randomly divided into sham and shock groups. The hemorrhagic shock model was duplicated. The sham group was given operation rather than bloodletting. (2) ASMCs were isolated with pronase E and mesenteric arteries A2 and A3 from sham and shock rats also isolated. (3) The changes of membrane potential of ASMCs and potassium channel were recorded using cell-attach and inside-out patch lamps. Results (1) The membrane potential of ASMCs changed from -41 mV to -65 mV two hours after hemorrhagic shock. (2) After shock, the conductance of BK Ca did not change, while the open probability (NPo) of BK Ca was enhanced and the reversal potential of BK Ca changed significantly. Conclusions Membrane hyperpolarization of ASMCs occurs posterior to hemorrhagic shock, the cause for which may be the activation increase of BK Ca .