TY - JOUR
T1 - Membrane potential gradient is carbon monoxide-dependent in mouse and human small intestine
AU - Sha, Lei
AU - Farrugia, Gianrico
AU - Harmsen, W. Scott
AU - Szurszewski, Joseph H.
PY - 2007/8
Y1 - 2007/8
N2 - The aims of this study were to quantify the change in resting membrane potential (RMP) across the thickness of the circular muscle layer in the mouse and human small intestine and to determine whether the gradient in RMP is dependent on the endogenous production of carbon monoxide (CO). Conventional sharp glass microelectrodes were used to record the RMPs of circular smooth muscle cells at different depths in the human small intestine and in wild-type, HO2-KO, and W/WV mutant mouse small intestine. In the wild-type mouse and human intestine, the RMP of circular smooth muscle cells near the myenteric plexus was -65.3 ± 2 mV and -58.4 ± 2 mV, respectively, and -60.1 ± 2 mV and -49.1 ± 1 mV, respectively, in circular smooth muscle cells at the submucosal border. Oxyhemoglobin (20 μM), a trapping agent for CO, and chromium mesoporphyrin IX, an inhibitor of heme oxygenase, abolished the transwall gradient. The RMP gradients in mouse and human small intestine were not altered by NG-nitro-L-arginine (200 μM). No transwall RMP gradient was found in HO2-KO mice andW/WV mutant mice. TTX (1 μM) and 1H-[1,2,4-]oxadiazolo[4,3-a]-quinoxalin-1-one (10 μM) had no effect on the RMP gradient. These data suggest that the gradient in RMP across the thickness of the circular muscle layer of mouse and human small intestine is CO dependent.
AB - The aims of this study were to quantify the change in resting membrane potential (RMP) across the thickness of the circular muscle layer in the mouse and human small intestine and to determine whether the gradient in RMP is dependent on the endogenous production of carbon monoxide (CO). Conventional sharp glass microelectrodes were used to record the RMPs of circular smooth muscle cells at different depths in the human small intestine and in wild-type, HO2-KO, and W/WV mutant mouse small intestine. In the wild-type mouse and human intestine, the RMP of circular smooth muscle cells near the myenteric plexus was -65.3 ± 2 mV and -58.4 ± 2 mV, respectively, and -60.1 ± 2 mV and -49.1 ± 1 mV, respectively, in circular smooth muscle cells at the submucosal border. Oxyhemoglobin (20 μM), a trapping agent for CO, and chromium mesoporphyrin IX, an inhibitor of heme oxygenase, abolished the transwall gradient. The RMP gradients in mouse and human small intestine were not altered by NG-nitro-L-arginine (200 μM). No transwall RMP gradient was found in HO2-KO mice andW/WV mutant mice. TTX (1 μM) and 1H-[1,2,4-]oxadiazolo[4,3-a]-quinoxalin-1-one (10 μM) had no effect on the RMP gradient. These data suggest that the gradient in RMP across the thickness of the circular muscle layer of mouse and human small intestine is CO dependent.
KW - Heme oxygenase 2
KW - Resting membrane potential
KW - Smooth muscle
UR - http://www.scopus.com/inward/record.url?scp=34547857713&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34547857713&partnerID=8YFLogxK
U2 - 10.1152/ajpgi.00037.2007
DO - 10.1152/ajpgi.00037.2007
M3 - Article
C2 - 17510199
AN - SCOPUS:34547857713
SN - 0193-1857
VL - 293
SP - G438-G445
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 2
ER -