EFFECT OF NOREPINEPHRINE ON ISOLATED CORONARY-ARTERY OF NORMAL AND MYOCARDIAL INFARCTED PIGS

  • 1 January 1982
    • journal article
    • research article
    • Vol. 10  (5) , 368-378
Abstract
The effect of norepinephrine, the adrenergic neurotransmitter, on isolated coronary arterial strips of normal and myocardial infarcted pigs was investigated to characterize the nature of adrenoceptors in this tissue. In small as well as large isolated coronary arterial strips of normal pigs, norepinephrine produced relaxation which was mediated through activation of .beta.1-adrenoceptors. While .alpha.-adrenoceptors were also present in large coronary arteries, they were absent in the small coronary arteries. In isolated coronary arterial strips dissected out from pigs in which myocardial infarction was induced, norepinephrine produced contraction, its .alpha.-adrenergic effect. This could be due to arterial hypoxia and/or sensitization of .alpha.-receptors present in the coronary artery.