EFFECTS OF MY-5116 ON EXPERIMENTAL ASTHMA IN RATS AND GUINEA PIGS

Abstract

The effects of MY-5116 (isoamyl 5, 6-dihydro-7, 8-dimethyl-4, 5-dioxo-4H-pyrano [3, 2-c]quinoline-2-carboxylate), a new anti-allergic agent and DSCG were compared by employing the models of experimental asthma in rats and guinea pigs. Experimental asthma in rats were prepared by using rats passively sensitized with mouse anti-OVA IgE serum (PCA titer 1:4096). Variations in breathing after an intravenous injection of antigen OVA were measured and the number of breaths and the volume of breathing were calculated. Breating decreased to a standstill or to a nearly arrested condition 30 sec after challenge and rapidly improved to normal level after 10 min. MY-5116(30mg/kg, p.o.)significantly inhibited the decreases in the number of breaths and the volume of breathing during a period between 30 sec and 1 min. Similar inhibition was observed in the animals treated with DSCG(10mg/kg, i.v.). Experimental asthma in guinea pigs was prepared by using guinea pigs passively sensitized with homologous anti-BPO・BGG IgE serum (PCA titer 1:2048). Under mild anesthesia with urethane, variations in breathing after challenge were measured through a tracheal cannula, and the number of breaths, the volume of breathing and the expiration divided by inspiration ratio were calculated. After challenge, breathing continuously changed between 3 min and 3 hr; the number of breaths and the volume of breathing decreased and the respiratory ratio increased. MY-5116(30 mg/kg, i.p.)significantly improved asthmatic symptoms during a period between 3 min and 3 hr and DSCG (10mg/kg i.v.) produced a partially significant inhibition of the symptoms after challenge, but the efficacy was less potent than that of MY-5116.