Procaine in cardioplegia: The effect on EDHF-mediated function in porcine coronary arteries
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AbstractObjectives: Hyperkalemia in cardioplegia impairs the endothelium-derived hyperpolarizing factor (EDHF)-mediated function. This study examined the effect of procaine in cardioplegia on the EDHF-mediated response in porcine coronary arteries. Methods: An isometric force study was performed in a myograph. Two rings taken from the same artery (diameter 200-450 μm) were incubated with Krebs solution (group I) or 20 mM K+ (group II) with/without procaine (1 mM) at 37°C for 1 hour. The EDHF-mediated relaxation was induced by bradykinin (BK, -10 ∼ -6.5 log M) after U46619 (-8 log M, in group I) or K+-precontraction (in group II) in the presence of indomethacin (7 μM), NG-nitro-L-arginine (300 μM), and hemoglobin (20 μM). The membrane potential of a single smooth muscle cell was measured by a microelectrode after superfusion with Krebs solution with/without procaine for 1 hour. Results: The EDHF-mediated relaxation was increased by the treatment with procaine with the EC50 shifted leftward (97.3 ± 0.6% vs. 83.0 ± 5.1% at - 7 log M and 99.4 ± 0.6% vs. 96.7 ± 1.6% at -6.5 log M, p < 0.05; EC50: -8.57 ± 0.24 vs. -7.92 ± 0.23 log M, p < 0.05). Procaine decreased the BK-induced hyperpolarization from -72.3 ± 0.7 mV to -68.8 ± 0.8 mV (-6.5 log M, p < 0.01). The EDHF-mediated relaxation in arteries exposed to 20 mM K+ was not altered by procaine (49.9 ± 7.4% vs. 55.8 ± 7.6%, p > 0.05). Conclusions: In the coronary arteries, procaine has a depolarizing effect but it enhances EDHF-mediated relaxation. Addition of procaine in cardioplegia did not change the EDHF-mediated endothelial function.
All Author(s) ListYang Q., Yim A.P.C., Arifi A.A., He G.-W.
Volume Number17
Issue Number5
PublisherBlackwell Publishing Inc.
Place of PublicationUnited Kingdom
Pages470 - 475
LanguagesEnglish-United Kingdom

Last updated on 2021-18-01 at 01:25