Abstract
Nitric oxide mediates nerve-induced hyperpolarization of circular smooth muscle of the esophagus. Two mechanisms are proposed to explain this hyperpolarization: an increase in K+ current or a decrease in Cl current. These studies test the hypothesis that nitric oxide increases a K+ current in esophageal smooth muscle. Three outward K+ currents are present in circular smooth muscle cells from the opossum esophagus. One current is a Ca2+-activated K+ current (I(KCa2+)). This current is inhibited by charybdotoxin. Whole cell currents were recorded from isolated opossum esophageal smooth muscle cells using the whole cell patch-clamp technique. These studies showed that I(KCa2+) is activated at potentials more positive than -30 mV. Bath application of S-nitroso-L-cysteine increased I(KCa2+) by 50% above control levels throughout the entire activation range of potentials. The enhanced current was reversible on washout. Either charybdotoxin, an inhibitor of I(KCa2+), or (R)-p-8-(4-chlorophenylthio)- guanosine 3',5'-cyclic monophosphorothioate, an inhibitor of protein kinase G, antagonized the increase in outward current induced by S-nitroso-L- cysteine. These data suggest that nitric oxide activates I(KCa2+) via the guanosine 3',5'-cyclic monophosphate-protein kinase G signal transduction pathway.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Gastrointestinal and Liver Physiology |
| Volume | 269 |
| Issue number | 4 32-4 |
| State | Published - 1995 |
| Externally published | Yes |
Fingerprint
Keywords
- charybdotoxin
- cyclic guanidino-monophosphate
- esophageal motility
- guanyl cyclase
- hyperpolarization
- patch clamp
- potassium currents
- smooth muscle
ASJC Scopus subject areas
- Physiology
- Gastroenterology
Cite this
Nitric oxide modulates a calcium-activated potassium current in muscle cells from opossum esophagus. / Murray, Joseph A; Shibata, E. F.; Buresh, T. L.; Picken, H.; O'Meara, B. W.; Conklin, J. L.
In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 269, No. 4 32-4, 1995.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Nitric oxide modulates a calcium-activated potassium current in muscle cells from opossum esophagus
AU - Murray, Joseph A
AU - Shibata, E. F.
AU - Buresh, T. L.
AU - Picken, H.
AU - O'Meara, B. W.
AU - Conklin, J. L.
PY - 1995
Y1 - 1995
N2 - Nitric oxide mediates nerve-induced hyperpolarization of circular smooth muscle of the esophagus. Two mechanisms are proposed to explain this hyperpolarization: an increase in K+ current or a decrease in Cl current. These studies test the hypothesis that nitric oxide increases a K+ current in esophageal smooth muscle. Three outward K+ currents are present in circular smooth muscle cells from the opossum esophagus. One current is a Ca2+-activated K+ current (I(KCa2+)). This current is inhibited by charybdotoxin. Whole cell currents were recorded from isolated opossum esophageal smooth muscle cells using the whole cell patch-clamp technique. These studies showed that I(KCa2+) is activated at potentials more positive than -30 mV. Bath application of S-nitroso-L-cysteine increased I(KCa2+) by 50% above control levels throughout the entire activation range of potentials. The enhanced current was reversible on washout. Either charybdotoxin, an inhibitor of I(KCa2+), or (R)-p-8-(4-chlorophenylthio)- guanosine 3',5'-cyclic monophosphorothioate, an inhibitor of protein kinase G, antagonized the increase in outward current induced by S-nitroso-L- cysteine. These data suggest that nitric oxide activates I(KCa2+) via the guanosine 3',5'-cyclic monophosphate-protein kinase G signal transduction pathway.
AB - Nitric oxide mediates nerve-induced hyperpolarization of circular smooth muscle of the esophagus. Two mechanisms are proposed to explain this hyperpolarization: an increase in K+ current or a decrease in Cl current. These studies test the hypothesis that nitric oxide increases a K+ current in esophageal smooth muscle. Three outward K+ currents are present in circular smooth muscle cells from the opossum esophagus. One current is a Ca2+-activated K+ current (I(KCa2+)). This current is inhibited by charybdotoxin. Whole cell currents were recorded from isolated opossum esophageal smooth muscle cells using the whole cell patch-clamp technique. These studies showed that I(KCa2+) is activated at potentials more positive than -30 mV. Bath application of S-nitroso-L-cysteine increased I(KCa2+) by 50% above control levels throughout the entire activation range of potentials. The enhanced current was reversible on washout. Either charybdotoxin, an inhibitor of I(KCa2+), or (R)-p-8-(4-chlorophenylthio)- guanosine 3',5'-cyclic monophosphorothioate, an inhibitor of protein kinase G, antagonized the increase in outward current induced by S-nitroso-L- cysteine. These data suggest that nitric oxide activates I(KCa2+) via the guanosine 3',5'-cyclic monophosphate-protein kinase G signal transduction pathway.
KW - charybdotoxin
KW - cyclic guanidino-monophosphate
KW - esophageal motility
KW - guanyl cyclase
KW - hyperpolarization
KW - patch clamp
KW - potassium currents
KW - smooth muscle
UR - http://www.scopus.com/inward/record.url?scp=0028871550&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028871550&partnerID=8YFLogxK
M3 - Article
C2 - 7485514
AN - SCOPUS:0028871550
VL - 269
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 4 32-4
ER -