Effects of captopril and enalaprilat on intracellular Ca2+, Na+ contents and pH in hypoxic and reoxygenated cardiomyocytes.
Abstract
AIM: To study the mechanisms of captopril (Cap) and enalaprilat (Ena) protective
effects on hypoxic and reoxygenated cardiac myocytes.
METHODS: Using fluorescent probes Fura 2-AM, BCECF/AM, SBFI/AM combined with
computer image processing techniques to measure intracellular ion concentrations.
RESULTS: [Ca2+]i (165 +/- 8 nmol.L-1) and [Na+]i (9.2 +/- 0.8 mmol.L-1) were
higher but [pH]i (6.7 +/- 0.3) was lower in hypoxic and reoxygenated myocytes
(196 +/- 14 nmol.L-1, 9.3 +/- 1.3 mmol.L-1, 6.61 +/- 0.19, respectively) than in
normal ones. Cap and Ena reduced [Ca2+]i (149 +/- 11 and 152 +/- 10 nmol.L-1
respectively) and intracellular acidosis (7.11 +/- 0.22 and 7.2 +/- 0.4,
respectively) during hypoxia. Cap also decreased [Na+]i in hypoxic myocytes (8.1
+/- 0.9 mmol.L-1). During reoxygenation, Cap decreased [Ca2+]i and [Na+]i but Ena
had no significant effect on them. Cap or Ena had no additive effect when
combined with verapamil (Ver).
CONCLUSION: Cap and Ena protected hypoxic and reoxygenated cardiomyocytes, but
the mechanisms were not the same.
Keywords:
effects on hypoxic and reoxygenated cardiac myocytes.
METHODS: Using fluorescent probes Fura 2-AM, BCECF/AM, SBFI/AM combined with
computer image processing techniques to measure intracellular ion concentrations.
RESULTS: [Ca2+]i (165 +/- 8 nmol.L-1) and [Na+]i (9.2 +/- 0.8 mmol.L-1) were
higher but [pH]i (6.7 +/- 0.3) was lower in hypoxic and reoxygenated myocytes
(196 +/- 14 nmol.L-1, 9.3 +/- 1.3 mmol.L-1, 6.61 +/- 0.19, respectively) than in
normal ones. Cap and Ena reduced [Ca2+]i (149 +/- 11 and 152 +/- 10 nmol.L-1
respectively) and intracellular acidosis (7.11 +/- 0.22 and 7.2 +/- 0.4,
respectively) during hypoxia. Cap also decreased [Na+]i in hypoxic myocytes (8.1
+/- 0.9 mmol.L-1). During reoxygenation, Cap decreased [Ca2+]i and [Na+]i but Ena
had no significant effect on them. Cap or Ena had no additive effect when
combined with verapamil (Ver).
CONCLUSION: Cap and Ena protected hypoxic and reoxygenated cardiomyocytes, but
the mechanisms were not the same.