Interaction of cholecystokinin (CCK-8) with agonist and antagonist of beta-adrenergic receptors in circulatory system of diabetic rats.
The interaction of C-terminal cholecystokinin octapeptide (CCK-8) with beta-adrenoceptors agonist (isoprenaline-ISO) and antagonist (propranolol) and their influence on arterial blood pressure and function of isolated heart in rats with streptozotocin-induced diabetes mellitus (DM) was studied. After blockade of beta-adrenoceptors with propranolol, the hypertensive effect of CCK-8 was observed in the control group but not in DM-group, whereas CCK-8 had no effect on arterial blood pressure in the both studied groups. Stimulation of beta-adrenoceptors with ISO exerted the hypotensive effect of CCK-8 similar as after administration of the amine alone in the control and diabetic rats. CCK-8 increased the cardiac contraction amplitude and had no effect on heart rate and coronary outflow in control hearts. The positive inotropic effect of the peptide was abolished in DM-group. After blockade of beta-adrenoceptors, CCK-8 decreased all studied parameters of isolated hearts, the effect was similar as after infusion of propranolol alone. In DM group, after blockade of beta-adrenoceptors CCK-8 evoked decrease in the cardiac contraction amplitude (as during infusion of propranolol) and heart rate (the effect was greater than that after beta-adrenoceptors antagonist). CCK-8 administrated with ISO increased amplitude, heart rate and decreased coronary outflow of isolated control heart as after administration of ISO alone: in DM-group only the positive inotropic effect was observed. DM modified the effect of CCK-8 in circulatory system of rats. CCK-8 evoked bradycardia independent of stimulation or blockade of beta-adrenoceptors, mainly in DM.
Wiśniewska
R J
RJ
Department of Pharmacology, Bialystok Medical Academy, Poland.
Wiśniewski
K
K
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004347:Drug Interactions; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012844:Sincalide / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011433:Propranolol; D007545:Isoproterenol; D012844:Sincalide