Effects of pindolol on the heart rate in the conscious dog with chronic atrioventricular block and the distribution of blood mass in the anesthetized dog.
The intrinsic sympathomimetic activity (ISA) of the adrenergic beta-blocker pindolol was studied by comparing its effects with those of propranolol in two experimental models: In the non-anesthetized dog with atrio-ventricular block created at least two months previously, propranolol at 0.078, 0.156 and 0.312 mg/kg depressed idioventricular automaticity without affecting atrial rate. Pindolol at 0.5 mg/kg raised atrial rate but left idioventricular rate unchanged. Beta-blockers depress the ventricular adrenergic tone which is strong in this model. With pindolol, this effect is offset by its ISA. Two successive injections of Thallium-201 enable variations in blood mass distribution caused by an agent administered between them to be studied. Isoprenaline increased blood flow in heart and skeletal muscles at the expense of lungs and kidneys. Pindolol (0.1 and 0.2 mg/kg) did not modify coronary blood flow, but increased muscular blood flow.
D000768:Anesthesia, General; D000818:Animals; D004285:Dogs; D006327:Heart Block / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects*; D010869:Pindolol / Q000494:pharmacology*; D011868:Radioisotopes; D012039:Regional Blood Flow / Q000187:drug effects*; D013793:Thallium; D013997:Time Factors
D011868:Radioisotopes; D013793:Thallium; D010869:Pindolol