Delayed rectifier potassium channels in ventricle and sinoatrial node of the guinea pig: Molecular and regulatory properties

1993 ◽  
Vol 7 (S3) ◽  
pp. 627-635 ◽  
Author(s):  
L. C. Freeman ◽  
R. S. Kass
Keyword(s):  
Potassium Channels ◽  
Guinea Pig ◽  
Sinoatrial Node ◽  
Delayed Rectifier ◽  
Regulatory Properties

Delayed rectification in single cells isolated from guinea pig sinoatrial node

1992 ◽  
Vol 262 (3) ◽  
pp. H921-H925 ◽  
Author(s):  
J. M. Anumonwo ◽  
L. C. Freeman ◽  
W. M. Kwok ◽  
R. S. Kass
Keyword(s):  
Guinea Pig ◽  
Sinoatrial Node ◽  
Single Cells ◽  
Equilibrium Potential ◽  
Delayed Rectifier ◽  
Experimental Conditions ◽  
Whole Cell ◽  
Voltage Range ◽  
Whole Cell Patch Clamp ◽  
Delayed Rectification

We have studied delayed rectifier K+ currents (IK) in cells isolated from the sinoatrial node (SAN) region of the guinea pig. Using whole cell patch-clamp procedures, we measured the voltage dependence of IK activation and IK kinetics and the IK equilibrium potential in 4.8 mM extracellular K concentration solutions. Experiments were designed to contrast properties of guinea pig SAN IK with those of IK recorded from SAN cells of the rabbit. We find that guinea pig SAN IK differs from IK recorded from single rabbit SAN cells in its activation threshold, and in the absence of inactivation of whole cell currents recorded over a wide voltage range. These results, along with the relative insensitivity of guinea pig SAN IK to E-4031 and lanthanum, suggest that under our experimental conditions, a strongly rectifying IK component (IK,r) is not the major component of delayed rectification in the guinea pig SAN, as it appears to be in SAN cells of the rabbit.

scholarly journals 4-aminopyridine- and dendrotoxin-sensitive potassium channels influence excitability of vagal mechano-sensitive endings in guinea-pig oesophagus

2002 ◽  
Vol 137 (8) ◽  
pp. 1195-1206 ◽  
Author(s):  
Vladimir P Zagorodnyuk ◽  
Bao Nan Chen ◽  
Marcello Costa ◽  
Simon J H Brookes
Keyword(s):  
Potassium Channels ◽  
Guinea Pig

scholarly journals Histamine H1 -receptor-mediated modulation of the delayed rectifier K+ current in guinea-pig atrial cells: opposite effects on IKs and IKr

1999 ◽  
Vol 128 (7) ◽  
pp. 1545-1553 ◽  
Author(s):  
Yasunori Matsumoto ◽  
Takehiko Ogura ◽  
Hiroko Uemura ◽  
Toshihiro Saito ◽  
Yoshiaki Masuda ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Delayed Rectifier ◽  
H1 Receptor ◽  
Histamine H1 Receptor ◽  
Atrial Cells ◽  
K Current

Effect of Prozac on whole cell ionic currents in lens and corneal epithelia

1995 ◽  
Vol 269 (1) ◽  
pp. C250-C256 ◽  
Author(s):  
J. L. Rae ◽  
A. Rich ◽  
A. C. Zamudio ◽  
O. A. Candia
Keyword(s):  
Potassium Channels ◽  
Single Channel ◽  
Ionic Currents ◽  
Current Amplitude ◽  
Human Lens ◽  
Delayed Rectifier ◽  
Open Probability ◽  
Channel Current ◽  
Single Channel Current ◽  
Ionic Conductances

Prozac (fluoxetine), a compound used therapeutically in humans to combat depression, has substantial effects on ionic conductances in rabbit corneal epithelial cells and in cultured human lens epithelium. In corneal epithelium, it reduces the current due to the large-conductance potassium channels that dominate this preparation. Its effects seem largely to decrease the open probability while leaving the single-channel current amplitude unaltered. In cultured human epithelium, currents from calcium-activated potassium channels and inward rectifiers are unaffected by Prozac. Delayed-rectifier potassium currents are reduced by Prozac in a complicated way that involves both gating and single-channel current amplitude. Fast tetrodotoxin-blockable sodium currents are also decreased by Prozac in this preparation. For all of these ion conductance effects, Prozac concentrations of 10(-5) to 10(-4) M are required. Whereas these levels are 10- to 100-fold higher than the plasma levels achieved in therapeutic use in humans, they are comparable to or less than levels needed for many other blockers of the ionic conductances studied here.

scholarly journals The effect of C-type natriuretic peptide on delayed rectifier potassium currents in gastric antral circular myocytes of the guinea-pig

2008 ◽  
pp. 55-62
Author(s):  
HY Xu ◽  
X Huang ◽  
M Yang ◽  
J-B Sun ◽  
L-H Piao ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Phosphodiesterase Inhibitor ◽  
Potassium Currents ◽  
Inhibitory Effect ◽  
Delayed Rectifier ◽  
Dependent Manner ◽  
Patch Clamp Technique ◽  
Whole Cell Patch Clamp ◽  
Dependent Protein ◽  
Gastric Myocytes

C-type natriuretic peptides (CNP) play an inhibitory role in smooth muscle motility of the gastrointestinal tract, but the effect of CNP on delayed rectifier potassium currents is still unclear. This study was designed to investigate the effect of CNP on delayed rectifier potassium currents and its mechanism by using conventional whole-cell patch-clamp technique in guinea-pig gastric myocytes isolated by collagenase. CNP significantly inhibited delayed rectifier potassium currents [I(K (V))] in dose-dependent manner, and CNP inhibited the peak current elicited by depolarized step pulse to 86.1+/-1.6 % (n=7, P<0.05), 78.4+/-2.6 % (n=10, P<0.01) and 67.7+/-2.3 % (n=14, P<0.01), at concentrations of 0.01 micromol/l, 0.1 micromol/l and 1 micromol/l, respectively, at +60 mV. When the cells were preincubated with 0.1 micromol/l LY83583, a guanylate cyclase inhibitor, the 1 ?micromol/l CNP-induced inhibition of I(K (V)) was significantly impaired but when the cells were preincubated with 0.1 micromol/l zaprinast, a cGMP-sensitive phosphodiesterase inhibitor, the 0.01 micromol/l CNP-induced inhibition of I(K (V)) was significantly potentiated. 8-Br-cGMP, a membrane permeable cGMP analogue mimicked inhibitory effect of CNP on I(K (V)). CNP-induced inhibition of I(K (V)) was completely blocked by KT5823, an inhibitor of cGMP-dependent protein kinase (PKG). The results suggest that CNP inhibits the delayed rectifier potassium currents via cGMP-PKG signal pathway in the gastric antral circular myocytes of the guinea-pig.

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