scholarly journals Voltage‐ and cation‐dependent inactivation of L‐type Ca 2+ channel currents in guinea‐pig ventricular myocytes

2002 ◽  
Vol 541 (3) ◽  
pp. 731-740 ◽  
Author(s):  
Ian Findlay
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Dependent Inactivation ◽  
Channel Currents

5-hydroxydecanoate inhibits ATP-sensitive K+ channel currents in guinea-pig single ventricular myocytes

1992 ◽  
Vol 220 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Tatsuto Notsu ◽  
Kiyokazu Ohhashi ◽  
Isao Tanaka ◽  
Hiroshi Ishikawa ◽  
Takeshi Niho ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
K Channel ◽  
Single Ventricular Myocytes ◽  
Channel Currents

Phospholamban deficiency alters inactivation kinetics of L-type Ca2+ channels in mouse ventricular myocytes

1997 ◽  
Vol 272 (2) ◽  
pp. H606-H612 ◽  
Author(s):  
H. Masaki ◽  
Y. Sato ◽  
W. Luo ◽  
E. G. Kranias ◽  
A. Yatani
Keyword(s):  
Ventricular Myocytes ◽  
Mammalian Species ◽  
Cardiac Cells ◽  
Inactivation Kinetics ◽  
Compensatory Mechanism ◽  
Channel Inactivation ◽  
Dependent Inactivation ◽  
Voltage Dependent ◽  
Channel Currents ◽  
Ca2 Channels

Entry of Ca2+ through voltage-dependent L-type Ca2+ channels is critical for contraction in cardiac cells. In recent studies, cells from phospholamban (PLB) knockout (PLB-KO) mouse hearts showed significantly increased basal contractility with enhanced sarcoplasmic reticulum (SR) Ca2+ uptake. To test whether these effects of PLB ablation were associated with alterations of L-type Ca2+ channel function, we compared the properties of Ca2+ channel currents (I(Ca)) in ventricular myocytes isolated from wild-type (WT) and PLB-KO mouse hearts. L-type Ca2+ channels from mouse myocytes exhibited voltage-dependent gating and sensitivity to dihydropyridine drugs, similar to other mammalian species, and these properties were not altered by PLB ablation. I(Ca) from both WT and PLB-KO cells revealed two (fast and slow) components of inactivation kinetics. However, the proportion of the faster component was significantly larger in PLB-KO cells. Ryanodine (10 microM) reduced the rate of inactivation of I(Ca) for both WT and PLB-KO cells, but the reduction was more prominent in PLB-KO cells compared with WT cells. In contrast, the inactivation in a Ba2+ solution could be fitted by a single exponential similar to the slower component in Ca2+, and this was not altered in PLB-KO cells. The increase in the fast Ca2+-dependent inactivation component in PLB-KO cells supports the hypothesis that Ca2+ released from the SR regulates Ca2+ channel inactivation by affecting the levels of Ca2+ near the channel and suggests that this may be an important compensatory mechanism in the hyperdynamic PLB-KO heart.

Voltage-dependent properties of macroscopic and elementary calcium channel currents in guinea pig ventricular myocytes

1986 ◽  
Vol 406 (5) ◽  
pp. 437-448 ◽  
Author(s):  
Terence F. McDonald ◽  
Adolfo Cavali� ◽  
Wolfgang Trautwein ◽  
Dieter Pelzer
Keyword(s):  
Guinea Pig ◽  
Calcium Channel ◽  
Ventricular Myocytes ◽  
Voltage Dependent ◽  
Channel Currents
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