Abstract
1) In intact mice, given doses of 2.5 mg/10 g of crude sanshotoxin, spontaneous limb movement was inhibited and akinesia was produced. Doses of more than 4.0 mg/10 g produced akinesia, abnormal posture, tremor of muscles, repeating clonic and tonic convulsions, dnd, then, opisthotonus and apnea followed by death. 2) The main Specific symptoms as mentioned above were observed in all unilaterally decrebrized mice. However, smaller doses, such as 2.5 mg/10 g, given by the intraperitoneal route, was sufficient to produce those symptoms. The same effect was shown with doses of 0.5 mg/10 g of the toxin administered locally on the mesencephalon. 3) The symptoms observed in unilaterally decerebrized animals did not differ from those in bilaterally decerebrized animals, except for tonic convulsions which were not always observed in the latter. 4) The somatic motor activity of the mice was estimated by UEHARA's method. When small doses of 0.4 mg/10 g was given, contradictory phenomena, i.e., inhibition and stimulation were produced. After the administration of 0.5 mg/10 g, however, there occurred a transient hyperkinesia and significant inhibitory movement, a decrease in amplitude and frequency of limb contraction, and an decrease in tonus which was followed by akinesia. Akinesia was produced more distinctly with doses of 1.5 mg/10 g. 5) Sanshotoxin, as well as bulbocapnine, acts synergetically with chloral hydrate and antipyrine. 6) These facts suggest that sanshotoxin acts on the extrapyramidal system extending from the corpus striatum to the diencephalon and mesencephalon.
