Effects of modified St Thomas' Hospital solution on coronary artery endothelium dependent relaxation in the isolated rat heart.
Addition of magnesium to a preservation solution such as St Thomas's Hospital solution has been shown to improve myocardial preservation. High concentration of magnesium can affect coronary artery endothelial-dependent relaxation. Isolated rat hearts were studied in the Langendorff apparatus to investigate whether magnesium-enriched hyperkalemic cardioplegic solution (HCS) could alter coronary endothelial function. Hearts in group 1 (n = 8) were perfused for 30 mins with a standard hyperkalemic cardioplegic solution (potassium chloride 24 mmol/L). Hearts in group 2 (n = 8) were perfused with modified St Thomas' Hospital solution (MST) containing 16 mmol/L of magnesium chloride and 24 mmol of potassium chloride. The endothelium dependent and endothelium independent relaxation of the coronary arteries were respectively assessed by infusing 5-hydroxytryptamine (5-HT) (1 x 10(-6) mol/L) and sodium nitroprusside (SNP) (1 x 10(-5) mol/L) before and after perfusion of cardioplegic solutions. Hearts in group 2 showed a reduction of the 5-HT-induced coronary flow increase following the MST exposure (before, 8.66 +/- 0.86 mL/min; after, 5.66 +/- 0.97 mL/min, P < 0.01) whereas hearts in group 1 were not significantly affected (before, 8.00 +/- 0.68 mL/min; after, 6.99 +/- 1.02 mL/min, not significant), suggesting endothelial dysfunction in the former. Coronary flow response to SNP was not affected in either group.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Cardiovascular Surgery, Montreal Heart Institute, Quebec.
R
R
Cartier
C
C
Hollmann
J
J
Buluran
F
F
Dagenais
D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D002122:Calcium Chloride / Q000494:pharmacology; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology / Q000601:surgery; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D015636:Magnesium Chloride / Q000494:pharmacology*; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects* / Q000502:physiology; D015425:Myocardial Reperfusion; D009599:Nitroprusside / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
D001639:Bicarbonates; D002314:Cardioplegic Solutions; C041711:St. Thomas' Hospital cardioplegic solution; D015636:Magnesium Chloride; D009599:Nitroprusside; D012701:Serotonin; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride