[General pharmacology of T-3761, a new oral quinolone antibacterial agent (2). Effect on the respiratory and cardiovascular systems, autonomic nervous system and other functions].

General pharmacological effects of T-3761, a new oral quinolone antibacterial agent, on the respiratory and cardiovascular systems, autonomic nervous system and other functions were investigated in laboratory animals. The results obtained are summarized as follows. 1. Respiratory and cardiovascular systems: Oral administration of T-3761 at doses of 100-1,000 mg/kg did not affect in conscious rats. But intravenous administration of T-3761 at doses of 10-100 mg/kg caused an increase in respiratory rate, induced hypotension, caused increase or decrease in heart rate and altered ECG patterns (elevation of T waves and reduction of voltage of QRS complexes, etc.) in anesthetized dogs. Intravenous administration of T-3761 at doses of 10-100 mg/kg showed respiratory rate increase or decrease, hypertension, heart rate decrease and ECG patterns changes (T waves elevation and extrasystole) in anesthetized rabbits. 2. Autonomic nervous system and smooth muscle organs: T-3761 increased the epinephrine-induced contraction of the isolated guinea pig vas deferens at concentration of 10(-5)-10(-4) g/ml. T-3761 decreased the acetylcholine-induced contraction of the isolated guinea pig ileum and epinephrine-induced relaxation of the isolated guinea pig trachea-chain at concentration of 10(-4) g/ml. T-3761 increased the norepinephrine-induced contraction of the isolated rabbit thoracic aorta at concentration of 10(-4) g/ml. Oral administration of T-3761 at a dose of 1,000 mg/kg exerted slight mydriasis in mice. 3. Digestive system: T-3761 decreased the spontaneous motilities of isolated ileum and colon at concentration of 10(-4) g/ml. Oral administration of T-3761 at a dose of 1,000 mg/kg inhibited gastric output and intestinal transit time in rats or mice. 4. Renal functions: Oral administration of T-3761 at a dose of 300 mg/kg increased Na+ excretion but did not affect PSP excretion in rats. 5. Hematological examinations: T-3761 showed no effects on resistance to hemolysis, blood coagulation and platelet aggregation in rabbits at concentration of 10(-6)-10(-4) g/ml. Oral administration of T-3761 at dose of 100-1,000 mg/kg did not affect bleeding time or blood glucose level in rats. 6. Miscellaneous effects: Intravenous administration of T-3761 at a dose of 100 mg/kg slightly inhibited the twitch tension of gastrocnemius in anesthetized rats. Oral administration of T-3761 at doses of 300-1,000 mg/kg exerted slight augmentation of carrageenin-induced hind paw edema in rats. From these results, it can be assumed that T-3761 had a wide safety margin as an oral antibacterial agent.