Abstract | BACKGROUND: METHODS AND RESULTS: We measured plasma ET-1 concentrations by radioimmunoassay in isolated blood-perfused neonatal lamb hearts before and after 2 hours of 10 degrees C cardioplegic ischemia and examined the effects of ET-1 and the endothelin-A (ET-A) receptor antagonist BE-18257B on the postischemic recovery of isolated hearts. ET-1 levels in coronary sinus blood before ischemia and at 0 and 30 minutes of reperfusion in 8 control hearts were constant (2.2 +/- 1.2 fmol/L, 2.2 +/- 1.3 fmol/L, and 2.5 +/- 1.0 fmol/L, respectively). In group 2 (n = 6), 10 mumol/L of BE-18257B was given just before reperfusion. In group 3 (n = 8), 10 pmol/L ET-1 was given just before the start of reperfusion. At 30 minutes of reperfusion, the ET-A antagonist hearts had significantly greater recovery of LV systolic (positive dP/dt and dP/dt at V10) and diastolic function (negative dP/dt), coronary blood flow (CBF), and MVo2 compared with controls (P < .05). The ET-1 hearts showed significantly reduced recovery of LV systolic (positive maximum and volume-normalized dP/dt) and diastolic (negative maximum dP/dt) function, CBF, and myocardial oxygen consumption compared with controls (P < .05). CONCLUSIONS: These results, combined with prior studies, suggest that I/R causes reduced production of endogenous vasodilators (eg, nitric oxide), leaving unopposed the vasoconstriction that is caused by the continued presence of ET-1. This imbalance may contribute to I/R injury. ET-A receptor antagonists may be useful therapeutic agents in reducing the injury that results from I/R.
|
Authors | T Hiramatsu, J Forbess, T Miura, S J Roth, M A Cioffi, J E Mayer Jr |
Journal | Circulation
(Circulation)
Vol. 92
Issue 9 Suppl
Pg. II400-4
(Nov 01 1995)
ISSN: 0009-7322 [Print] United States |
PMID | 7586445
(Publication Type: Journal Article)
|
Chemical References |
- Endothelin Receptor Antagonists
- Endothelins
- Peptides, Cyclic
- Receptor, Endothelin A
- cyclo(glutamyl-alanyl-isoleucyl-leucyl-tryptophyl)
|
Topics |
- Animals
- Biological Assay
- Coronary Circulation
- Endothelin Receptor Antagonists
- Endothelins
(blood, pharmacology)
- Heart
(drug effects)
- Heart Arrest, Induced
- Hypothermia, Induced
- Myocardial Ischemia
(physiopathology)
- Oxygen Consumption
- Peptides, Cyclic
(pharmacology)
- Receptor, Endothelin A
- Reference Values
- Sheep
- Ventricular Function, Left
|