|
|
||||||||
Department of Physiology and Biophysics, Mayo Clinic, Rochester, MN 55905.
1. A perforated patch clamp technique was used to study an outward potassium current in freshly dissociated circular smooth muscle cells of the canine jejunum. 2. A voltage-dependent outward current was identified which was highly potassium selective, weakly holding voltage sensitive, increased its open probability at -65 mV, and reached unit open probability at +5 mV. 3. Quinidine (0.1-1 mM) and tetraethylammonium ion (TEA) (10-50 mM), blocked the potassium current in a dose-dependent manner. Blockade of the outward potassium current was accompanied by membrane depolarization which reversed on removal of the blocker from the bathing solution. 4. Mefenamic and flufenamic acids, non-steroidal anti-inflammatory agents in the fenamate group, were potent activators of the current. Activation was accompanied by hyperpolarization of the membrane with a mean shift in the membrane voltage of 22 mV. 5. It was concluded that the outward potassium current is a major regulator of the resting membrane voltage in isolated circular smooth muscle cells of the canine jejunum. Fenamates activated this current with potentially profound effects on cellular excitability.
This article has been cited by other articles:
![]() |
K. E. Gardam, J. E. Geiger, C. M. Hickey, A. Y. Hung, and N. S. Magoski Flufenamic Acid Affects Multiple Currents and Causes Intracellular Ca2+ Release in Aplysia Bag Cell Neurons J Neurophysiol, July 1, 2008; 100(1): 38 - 49. [Abstract] [Full Text] [PDF] |
||||
![]() |
Q. Zhang, C. Cao, Z. Zhang, W. G. Wier, A. Edwards, and T. L. Pallone Membrane current oscillations in descending vasa recta pericytes Am J Physiol Renal Physiol, March 1, 2008; 294(3): F656 - F666. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. O. Suadicani, C. F. Brosnan, and E. Scemes P2X7 Receptors Mediate ATP Release and Amplification of Astrocytic Intercellular Ca2+ Signaling J. Neurosci., February 1, 2006; 26(5): 1378 - 1385. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. R. Strege, C. E. Bernard, Y. Ou, S. J. Gibbons, and G. Farrugia Effect of mibefradil on sodium and calcium currents Am J Physiol Gastrointest Liver Physiol, August 1, 2005; 289(2): G249 - G253. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Srinivas and D. C. Spray Closure of Gap Junction Channels by Arylaminobenzoates Mol. Pharmacol., June 1, 2003; 63(6): 1389 - 1397. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. R. Strege, A. N. Holm, A. Rich, S. M. Miller, Y. Ou, M. G. Sarr, and G. Farrugia Cytoskeletal modulation of sodium current in human jejunal circular smooth muscle cells Am J Physiol Cell Physiol, January 1, 2003; 284(1): C60 - C66. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. N. Holm, A. Rich, M. G. Sarr, and G. Farrugia Whole cell current and membrane potential regulation by a human smooth muscle mechanosensitive calcium channel Am J Physiol Gastrointest Liver Physiol, December 1, 2000; 279(6): G1155 - G1161. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. I. Akbarali, H. Thatte, X. D. He, W. R. Giles, and R. K. Goyal Role of HERG-like K+ currents in opossum esophageal circular smooth muscle Am J Physiol Cell Physiol, December 1, 1999; 277(6): C1284 - C1290. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Lu, B. Mazet, M. G. Sarr, and J. H. Szurszewski Effect of nitric oxide on calcium-activated potassium channels in colonic smooth muscle of rabbits Am J Physiol Gastrointest Liver Physiol, May 1, 1998; 274(5): G848 - G856. [Abstract] [Full Text] [PDF] |
||||
![]() |
G Farrugia, S Nitecki, G J Harty, M Camilleri, and J H Szurszewski The effect of flufenamic acid on gastrointestinal myoelectrical activity and transit time in dogs Gut, February 1, 1998; 42(2): 258 - 265. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Farrugia, S. M. Miller, A. Rich, X. Liu, M. D. Maines, J. L. Rae, and J. H. Szurszewski Distribution of heme oxygenase and effects of exogenous carbon monoxide in canine jejunum Am J Physiol Gastrointest Liver Physiol, February 1, 1998; 274(2): G350 - G358. [Abstract] [Full Text] [PDF] |
||||
![]() |
H.-S. Wang, J. E. Dixon, and D. McKinnon Unexpected and Differential Effects of Cl- Channel Blockers on the Kv4.3 and Kv4.2 K+ Channels : Implications for the Study of the Ito2 Current Circ. Res., November 19, 1997; 81(5): 711 - 718. [Abstract] [Full Text] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |