Cardiohemodynamic effects of bopindolol in normotensive conscious dogs. A comparative study with pindolol
Ishibashi, T.; Mitomi, A.; Tatebe, S.; Imai, S.
Arzneimittel-Forschung 39(4): 454-457
1989
ISSN/ISBN: 0004-4172 PMID: 2568836 Document Number: 336857
Cardiohemodynamic effects and the .beta.-blocking action of a new .beta.-adrenoceptor blocking agent, bopindolol (Sandonorm) were compared with those of pindolol in conscious unrestarined dogs. The intravenous injection of pindolol (3-100 .mu.g/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 .mu.g/kg). These changes were antagonized by propranolol (3 mg/kg). Isoprenaline (isoproterenol, 0.1 .mu.g/kg)-induced tachycardia was inhibited dose-dependently by both .beta.-blockers to similar degresses. 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.1-adrenoceptor. Instead it produced the partial agonist activity at the .beta.2-adrenoceptor at the highest dose tested.