Abstract
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.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 297-310 |
| Number of pages | 14 |
| Journal | Journal of Physiology |
| Volume | 468 |
| State | Published - 1993 |
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ASJC Scopus subject areas
- Physiology
Cite this
Characterization of an outward potassium current in canine jejunal circular smooth muscle and its activation by fenamates. / Farrugia, Gianrico; Rae, J. L.; Szurszewski, J. H.
In: Journal of Physiology, Vol. 468, 1993, p. 297-310.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization of an outward potassium current in canine jejunal circular smooth muscle and its activation by fenamates
AU - Farrugia, Gianrico
AU - Rae, J. L.
AU - Szurszewski, J. H.
PY - 1993
Y1 - 1993
N2 - 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.
AB - 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.
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UR - http://www.scopus.com/inward/citedby.url?scp=0027325740&partnerID=8YFLogxK
M3 - Article
C2 - 8254511
AN - SCOPUS:0027325740
VL - 468
SP - 297
EP - 310
JO - Journal of Physiology
JF - Journal of Physiology
SN - 0022-3751
ER -