Vasa recta pericytes express a strong inward rectifier K+ conductance
| Autor: | Thomas L. Pallone, Whaseon Lee-Kwon, Chunhua Cao, Jae Hwan Goo |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Vascular smooth muscle
Patch-Clamp Techniques Physiology Cesium In Vitro Techniques Membrane Potentials Rats Sprague-Dawley Physiology (medical) medicine Repolarization Animals Patch clamp Potassium Channels Inwardly Rectifying Ouabain Kidney Medulla Chemistry Inward-rectifier potassium ion channel Vasa recta Anatomy Hyperpolarization (biology) Potassium channel Capillaries Rats Electrophysiology medicine.anatomical_structure Barium Biophysics Potassium Pericytes |
| Zdroj: | American journal of physiology. Regulatory, integrative and comparative physiology. 290(6) |
| ISSN: | 0363-6119 |
| Popis: | Strong inward rectifier potassium channels are expressed by some vascular smooth muscle cells and facilitate K+-induced hyperpolarization. Using whole cell patch clamp of isolated descending vasa recta (DVR), we tested whether strong inward rectifier K+ currents are present in smooth muscle and pericytes. Increasing extracellular K+ from 5 to 50 and 140 mmol/l induced inward rectifying currents. Those currents were Ba2+ sensitive and reversed at the K+ equilibrium potential imposed by the electrode and extracellular buffers. Ba2+ binding constants in symmetrical K+ varied between 0.24 and 24 μmol/l at −150 and −20 mV, respectively. Ba2+ blockade was time and voltage dependent. Extracellular Cs+ also blocked the inward currents with binding constants between 268 and 4,938 μmol/l at −150 and −50 mV, respectively. Ba2+ (30 μmol/l) and ouabain (1 mmol/l) depolarized pericytes by an average of 11 and 24 mV, respectively. Elevation of extracellular K+ from 5 to 10 mmol/l hyperpolarized pericytes by 6 mV. That hyperpolarization was reversed by Ba2+ (30 μmol/l). We conclude that strong inward rectifier K+ channels and Na+-K+-ATPase contribute to resting potential and that KIR channels can mediate K+-induced hyperpolarization of DVR pericytes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|