Anti-aconitinic effects of caci2 and atropine

In anesthetized rabbits con-tinuous iv infusion of 0.05% aconitine 0.06-0.08 mg/kg slowed the respiration rate significantly for about 10 s, while 0.33-0.35 mg/kg decreased the depth of breathing by 50%. Slow iv of CaClz . 200 mg/kg antago-nized the fibrillating effect of aconitine on guinea pigs and its respiratory depression action on rabbits. The LDso curve of CaCl2 was parallel to that of aconitine. CaCl2 (ip 2/5 LD60/kg) increased the LD60 0f aconitine t0 1.55-fold. Atropine increased the LD60 0f aconi-tine or CaClz. Atropine and CaC12 used in combination increased the LD60 0f aconi- tine no more than they did separately. At.ropine counteracted the antagonistic effect of CaC12 against the shallow respi-ration caused by large dose of aconitine (0.33-0.35 mg/kg).