Cardiohemodynamic effects of bopindolol in normotensive conscious dogs. A comparative study with pindolol.
Cardiohemodynamic effects and the beta-blocking action of a new beta-adrenoceptor blocking agent, bopindolol (Sandonorm) were compared with those of pindolol in conscious unrestrained dogs. The intravenous injection of pindolol (3-100 micrograms/kg) increased the heart rate and decreased the total peripheral resistance dose-dependently and markedly, while the same doses of bopindolol had no effect on the heart rate and decreased the total peripheral resistance only at the maximum dose (100 micrograms/kg). These changes were antagonized by propranolol (3 mg/kg). Isoprenaline (isoproterenol, 0.1 microgram/kg)-induced tachycardia was inhibited dose-dependently by both beta-blockers to similar degrees. While the decrease in the total peripheral resistance by isoprenaline was inhibited by pindolol dose-dependently, the inhibition by lower doses of bopindolol was not so marked; the inhibition became greater as the doses of bopindolol were increased. These results indicate that bopindolol is a beta 1-selective beta-blocker with an affinity to this subtype of the beta-adrenoceptor comparable to that of pindolol. Unlike pindolol, it exerted no partial agonist activity at the beta-adrenoceptor. Instead it produced the partial agonist activity at the beta 2-adrenoceptor at the highest dose tested.
Ishibashi
T
T
Department of Pharmacology, Niigata University School of Medicine, Japan.
Mitomi
A
A
Tatebe
S
S
Imai
S
S
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects*; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D010869:Pindolol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology
D000319:Adrenergic beta-Antagonists; D011433:Propranolol; D010869:Pindolol; C036007:bopindolol