The pharmacological and toxicological effects of two Formosan snake venoms, Agkistrondon acutus Gunther (A. a. V. ) and Trimeresurus mucrosquamatus Cantor (T. m. V. ), were comparatively examined in mice, rats and rabbits.
(1) The maximal tolerable or minimal lethal dose of A. a. V. administered into the ear vein of rabbits was about 1 mg/kg, which dose caused a transient respiratory stimulation followed by a gradual inhibition, leading to respiratory paralysis following a precipitous fall of blood pressure 30 to 90 minutes after administration. The maximal tolerable or minimal lethal. dose of T. m. V. in rabbits was 0.5 mg/kg, which dose caused respiratory paralysis and a fall of blood pressure soon after administration; if death did not occur immediately after administration, paralysis of respiration following a precipitous fall of blood pressure was not to be observed as in the case of A. a. V. administration.
(2) The LD50 of A. a. V. and T. m. V. subcutaneously injected in mice were 0.014 mg and 0.100 mg/10g respectively within 24 hours after administration. But in the lethal A. a. V. cases death occured within 3 hours, whereas, in the lethal T. m. V. cases ranged over a period of from 5 minutes to 24 hours. The toxic symptom brought on by A. a. V. were clonic convulsion with respiratory paralysis, whereas those brought on by T. m. V. were motor depression and quiet death. The LD50 of A. a. V. was increased by the previous subcutaneous administration of ε-aminocapronic acid in a dose of 100mg/10g 30 minutes before A. a. V. administration, but the lethal dose of T. m. V. was conversely decreased by the drug.
(3) The intracutaneous reactions of T. m. V. in rabbits was hemorrhagic and exudative, and stronger than those of A. a. V..
(4) The atrial movement of rabbits was arrested by the application of A. a. V. in the concentration of 3×10-5g/ml, but not by the addition of T. m. V. even in the concentration of 9×10-5g/ml.
(5) Rat diaphragm contraction by electric stimulation was suppressed by the application of A. a. V. in the concentration of 10-5 g/ml, but was suppressed by that of T. m. V. in the concentration of 5×10-5g/ml.
(6)The intestinal movement of rabbits was slightly augmented by the application of A. a. V. or T. m. V.. These experimental results led to the following conclusions: a) the lethal factors of these snake venoms differ from their inflammatory factors, b) the lethal elect of A. a. V. is greater than that of T. m. V. but the inflammatory effect of A. a. V. is less than that of. T. m. V..
