[Hemorrhagic shock induces changes in large-conductance Ca(2+) dependent K+ channel activity in mesenteric arterial smooth muscle cells of rats].
The purpose of the present study was to detect changes in the activity of large-conductance Ca(2+)activated K(+) channel (BK(Ca)) during hemorrhagic shock (HS) in mesenteric arterial vascular smooth muscle cells using inside-out patches. The HS rat model was produced with withdrawing blood from the femoral artery. The results showed that the BK(Ca) activity was inhibited with decreased open probability (P(o)) and single-channel conductance. The decrease of P(o) resulted from an increase of the close time constant (tau(cs)) in the compensatory stage of HS, i.e.the term of hyperresponse of the muscle to norepinephrine (NE) (HS lasted for about 40 min). During the decompensation stage of HS, i.e. the period of hyporesponse to NE (HS developed for 3 h), the BK(Ca) activity was enhanced with the increase in single-channel conductance and P(o) which was a result of a decrease in tau(cs).
Kai
L
L
Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042. zfwang@sunm.shcnc.ac.cn
Hu
D Y
DY
Wang
Z F
ZF
Shi
Y L
YL
Liu
L M
LM
D000818:Animals; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009638:Norepinephrine; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012771:Shock, Hemorrhagic / Q000378:metabolism*
D051036:Large-Conductance Calcium-Activated Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D009638:Norepinephrine