[Ca++ dependence of the contraction of coronary artery segments in response to norepinephrine after beta-adrenergic blockade].
The effect of external calcium concentration on the NE-induced contraction after beta-adrenergic blocking was studied in vitro. It resulted that the effect of NE was enhanced by increase, or reduced by decrease of calcium concentration. NE-induced contraction was not abolished when the bathing fluid was Ca++-free. The disappearance of the NE effect was only obtained in preparations treated with EDTA and perfused with Ca++-free Ringer-Locke solution. It is concluded that NE induced contraction after beta-adrenergic blocking is Ca++-dependent and on the tissue bound Ca++.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D003331:Coronary Vessels / Q000187:drug effects*; D004357:Drug Synergism; D004492:Edetic Acid / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D014661:Vasoconstriction / Q000187:drug effects*
D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004492:Edetic Acid; D011433:Propranolol; D002118:Calcium; D009638:Norepinephrine
Ca++-dipendenza della contrazione di segmenti di arteria coronaria in rispo sta alla noradrenalina dopo blocco beta-adrenergico.