The use of radioactive microspheres to compare the effects of hydralazine, guanethidine and SK & F 24260 on the redistribution of cardiac output in anaesthetized rabbits.
1 The use of radioactive microspheres is described for the measurement of cardiac output in anaesthetized rabbits and its redistribution after the administration of drugs which lower blood pressure. 2 Hydralazine increased peripheral vascular conductance by 123%. The vascular beds in which it had most effect were those of the carcass (mainly muscle) and the kidneys. 3 SK&F 24260, (1,4 dihydro-2, 6-dimethyl-4(2-trifluoremethylpheny)-3,5,-pyridinedicarboxylic acid diethyl ester), had similar vasocilator actions. Its effect in the carcass contributed relatively more to the increase of total peripheral conductance. It also caused a remarkable degree of cerebral vasodilatation. 4 Guanethidine had a relatively small effect on total peripheral conductance and lowered blood pressure mainly by reducing stroke volume and cardiac output.
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects*; D004095:Dihydropyridines; D006145:Guanethidine / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006830:Hydralazine / Q000494:pharmacology*; D006845:Hydrocarbons, Fluorinated / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008297:Male; D008863:Microspheres; D011725:Pyridines / Q000494:pharmacology*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013326:Strontium Radioisotopes; D013997:Time Factors
D004095:Dihydropyridines; D006845:Hydrocarbons, Fluorinated; D011725:Pyridines; D013326:Strontium Radioisotopes; C001040:1,4-dihydro- 2,6-dimethyl-4-(2-(trifluoromethyl)phenyl)-3,5- pyridinedicarboxylic acid diethyl ester; D006830:Hydralazine; D006145:Guanethidine