Plasma
catecholamine levels rise, and myocardial beta(1)-adrenoceptor (beta(1)-AR) sensitivity increases during
ischemia. These factors enhance myocardial injury and cardiac dysfunction. beta(1)-AR blockers are clinically used to protect heart against
ischemia and to improve cardiac dysfunction in patients with
ischemic heart disease, but these agents often cause intolerable side effects. To examine the potential cardioprotective effect of
therapy with antisense-
oligodeoxynucleotides directed at beta(1)-AR
mRNA (beta(1)-AS-ODNs) during
myocardial ischemia-reperfusion, Sprague-Dawley rats were treated with beta(1)-AS-ODNs or inverted-
oligodeoxynucleotides (IN-ODNs), each 200 microg/rat. Hearts were excised, perfused, and subjected to global
ischemia (30 min) followed by reperfusion (30 min). Other rats were given selective beta(1)-AR blocker
atenolol (2 mg/kg) or saline before excising the hearts.
Ischemia-reperfusion resulted in cardiac dysfunction, indicated by an increase in coronary perfusion pressure and left ventricular end-diastolic pressure and a decrease in developed left ventricular pressure, as well as evidence of lipid peroxidation in saline-treated rats (all P <.05 versus control values). Administration of AS-ODNs or
atenolol, but not IN-ODNs, protected hearts against functional deterioration and lipid peroxidation (P <.05 versus saline or IN-ODNs treatment). AS-ODNs
therapy appeared to be equivalent to
atenolol in these effects. Expression of beta(1)-AR
protein as well as
mRNA in the myocardium were markedly up-regulated after
ischemia-reperfusion, and treatment with beta(1)-AS-ODNs, but not
atenolol, decreased the rise in enhanced expression of beta(1)-AR. These observations imply that beta(1)-AS-ODNs can ameliorate cardiac dysfunction after
ischemia-reperfusion by reducing the expression of beta(1)-AR in the ischemic-reperfused myocardium.