[Insulin and endothelium-dependent mechanisms in regulation of coronary circulation].
Changes in cardiohemodynamics after intravenous administration of insulin (1.0 IU/kg) were investigated on anaesthetized dogs with closed chest. During the first 5-10 min (phase 1 of the response), coronary vasoconstriction, an enhancement of the cardiac activity and an increase in a coronary arteriovenous oxygen difference were observed. During the next 25-30 min (phase II) a long-term coronary dilation, an attenuation of the cardiac contractility and a decrease in the coronary arteriovenous oxygen difference occurred. An injection of insulin after preliminary inhibiting NO-synthase (L-MANE, intracoronary infusion, 1.0 mg/min), guanilatcyclase (100 micrograms ouabaine, intracoronary injection), Na+, K(+)-ATPase (methylene blue, intracoronary infusion, 5 mg/min) induced coronary vasoconstriction. Inhibiting muscarinic receptors with atropine (0.5 mg/kg i.v.) attenuated or absolutely abolished haemodynamic responses induced by insulin. Under beta-adrenergic blockade by propranolol (2.0 mg/kg i.v.) administrations of insulin resulted in coronary constriction, an augmentation of cardiac contractility and an elevation of the arterial blood pressure. The conception has being developed, according to which the degree and trends of induced by insulin changes in cardio-haemodynamics depend on the initial levels the sympathetic and parasympathetic activities, as well as on the synthesis of endothelial vaso- and cardiotropic substances, and their interactions with these systems.
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D004285:Dogs; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D007275:Injections, Intravenous; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010042:Ouabain / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects*
D004791:Enzyme Inhibitors; D007328:Insulin; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D010042:Ouabain; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D000254:Sodium-Potassium-Exchanging ATPase; D019331:NG-Nitroarginine Methyl Ester