Effect of two newly synthesized β blockers, DPJ 955 and DPJ 890 on ECG of anaesthetized mice

Two newly synthesized β blockers namely DPJ 955 and DPJ 890 were studied for its effect on (1) ECG of anaesthetized mice when administered alone and (2) ability to inhibit isoprenaline induced tachycardia (anti-arrhythmic activity) in mice. Intravenous administration of DPJ 955 and DPJ 890 showed immediate onset of action and peak effect was observed at about 15 to 30 min. DPJ 890 had intermediate duration of action while DPJ 955 had long duration of action when administered alone. Pretreatment with DPJ 955 and DPJ 890 antagonized the isoprenaline-induced tachycardia. The anti-arrhythmic activity was in the order of DPJ 890 > atenolol > DPJ 955 > propranolol. In conclusion, DPJ 890 showed good anti-arrhythmic potential.