Procaine in cardioplegia: the effect on EDHF-mediated function in porcine coronary arteries.

Abstract

OBJECTIVES:

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 microm) were incubated with Krebs solution (group I) or 20 mM K+ (group II) with/without procaine (1 mM) at 37 degrees C for 1 hour. The EDHF-mediated relaxation was induced by bradykinin (BK, -10 approximately -6.5 log M) after U46619 (-8 log M, in group I) or K+-precontraction (in group II) in the presence of indomethacin (7 microM), NG-nitro-L-arginine (300 microM), and hemoglobin (20 microM). 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.

• Authors: Qin Yang, Anthony P C Yim, Ahmed A Arifi, Guo-Wei He
• Journal: Journal of cardiac surgery (J Card Surg) 2002 Sep-Oct Vol. 17 Issue 5 Pg. 470-5 ISSN: 0886-0440 [Print] United States
• PMID: 12630551 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anesthetics, Local
• Bicarbonates
• Biological Factors
• Cardioplegic Solutions
• St. Thomas' Hospital cardioplegic solution
• endothelium-dependent hyperpolarization factor
• Sodium Chloride
• Procaine
• Potassium Chloride
• Magnesium
• Calcium Chloride

Topics

• Algorithms
• Anesthetics, Local (pharmacology)
• Animals
• Bicarbonates
• Biological Factors (physiology)
• Calcium Chloride
• Cardioplegic Solutions
• Computer Graphics
• Coronary Vessels (drug effects, physiology)
• Heart Arrest, Induced
• Magnesium
• Membrane Potentials (drug effects, physiology)
• Models, Animal
• Muscle Relaxation (drug effects)
• Muscle, Smooth, Vascular (drug effects, physiology)
• Potassium Chloride
• Procaine (pharmacology)
• Sodium Chloride
• Swine