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Effects of Glucose on Transmembrane Ionic Current of Ventricular Myocytes in Guinea Pig

AI Jing, JIAO Jun-dong, WANG He, DU Zhi-min, YANG Bao-feng*   

  1. 1.Department of Pharmacology, Harbin Medical University, Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150086, China;
    2.State Base for Drug Clinical Trial, Harbin Medical University, Harbin 150086, China
  • Received:2004-04-20 Revised:2004-08-10 Online:2004-09-15 Published:2004-09-15
  • Contact: YANG Bao-feng*

Abstract: Aim To determine the effects of glucose on APD, IK1, IK, ICa-L of ventricular myocytes in guinea pigs. Methods Whole-cell patch-clamp technique was used to record the changed action potential ionic current induced by glucose of single cell in guinea pig ventricular myocytes, to compare the action of 0, 10 and 20 mmol·L-1 glucoses on transmembrane ionic current. Results (1) Compared with 10 mmol·L-1 glucose concentrations, 0 and 20 mmol·L-1 glucose both shortened APD of ventricular myocytes (P<0.05). (2) The inward components of IK1 density were maximal when the glucose concentration was at 10 mmol·L-1. Normalized I-V relationships showed that both 0 and 20 mmol·L-1 glucose produced a left-shift of I-V curve. The reverse potential changed from -72.4 mV to -64.6 mV. (3) Compared with 10 mmol·L-1, both 0 and 20 mmol·L-1 glucose markedly increased the ICa-L amplitude and density. The ICa-L current density was (-8.035±0.82) pA/pF (n=8) at a test potential of 10 mV when the glucose concentration was 10 mmol·L-1. But its current density decreased to (-5.45±0.67) pA/pF and (-6.50±0.56) pA/pF when glucose concentrations were 0 and 20 mmol·L-1, respectively. (4) The current densities of IK were (18.96±2.86) pA/pF, (8.66±1.87) pA/pF, and (15.32±3.12) pA/pF, at +70 mV for 0, 10 and 20 mmol·L-1 glucoses, respectively. Conclusion Glucose in different concentrations has different effects on APD, IK1, IK, and ICa-L of single ventricular myocyte in guinea pigs. There are similar actions of 0 and 20 mmol·L-1 glucoses on the transmembrane ionic current of ventricular myocytes in guinea pigs.

Key words: glucose, glucose, calcium channel, calcium channel, potassium channel, potassium channel, patch-clamp technique, patch-clamp technique

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