[Hemodynamic mechanisms of the hypotensive effect of cobalt in anesthetized rats].
Hemodynamic mechanisms of Co(2+)-evoked hypotension were studied in pentobarbital--anesthetised male Wistar rats. Bolus i.v. administration of cobalt sulphate (30, 90 and 270 mg/kg of Co) evoked dose-dependent hypotension followed by tachycardia and increase in left ventricular contractility index (dP/dt/P). Administration of beta-adrenoblocker propranolol (2 mg/kg) attenuated Co evoked (270 ug/kg) tachycardia and unmasked its cardiodepressive effects (dP/dt/P decreased by 11% and end-diastolic pressure increased by 55%). Cardiodepressive Co2+ effects were prevented by administration of verapamil (0.4 mg/kg). In the second group hemodynamic mechanisms of Co-evoked hypotension were studied with radioactive microspheres. Co2+ infusion (55 mg/kg) lowered blood pressure (in average by -11%) by decreasing total peripheral resistance (-25%). Cardiotoxic effects were obtained with a ++larger dose 80 mg/kg/min. It is concluded that Co decreased blood pressure by vasodilatator action and its cardiotoxic effects attenuated by sympathetic counterregulation and may be prevented by verapamil.
S F
SF
Dugin
N V
NV
Zakharova
O S
OS
Medvedev
D000768:Anesthesia, General; D000818:Animals; D003035:Cobalt / Q000008:administration & dosage* / Q000009:adverse effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology; D007022:Hypotension / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D010424:Pentobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014665:Vasodilator Agents
D014665:Vasodilator Agents; D003035:Cobalt; C026305:cobalt sulfate; D010424:Pentobarbital
Gemodinamicheskie mekhanizmy gipotenzivnogo deĭstviia kobal'ta u narkotizirovannykh krys.