[Effect of chronic hypoxia on the calcium and potassium current of myocytes of the right ventricle in guinea pig].
To explore the effect of chronic hypoxia on calcium and potassium currents of the right ventricle myocytes in the guinea pig, the cell membrane capacities, calcium and delayed rectifier potassium current were recorded using the whole-cell patch clamp technique from single right ventricle myocytes in guinea pigs under chronic hypoxia. The result demonstrated that the cell membrane capacities of the hypoxic group were larger than those of the control; between test potential of -20 mV to +20 mV, the calcium current density of the myocytes of the chronic hypoxic group was less than that of the control; the amplitude of IK of the myocytes of the chronic hypoxia group were less than that of the control group between test potential of +20 mV to +60 mV, and the IK density of the hypoxic group was also less than that of the control group between -20 mV to +60 mV. Consequently, it is suggested that chronic hypoxia may cause an increase of the membrane capacity, a decrease of the calcium current density of ventricle myocytes and a delay of the rectifier potassium current amplitude and density. All these observations provide information for the ionic basis of the attenuated contraction of cardiac muscles and prolonged action potential duration of hypoxic guinea pigs.
Bie
B H
BH
Division of Respiratory Medicine, Tongji Hospital, Tongji Medical University, Wuhan 430030.
Zhang
Z X
ZX
Xu
Y J
YJ
Yue
Y K
YK
Tang
M
M
D000200:Action Potentials; D000818:Animals; D015220:Calcium Channels / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles; D006976:Hypertension, Pulmonary / Q000378:metabolism / Q000503:physiopathology*; D000860:Hypoxia / Q000150:complications*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology; D011897:Random Allocation
D015220:Calcium Channels; D015221:Potassium Channels