Abstract: To study the analgesic effect and ameliorating effect of cobra cardiotoxin (CTX) on learning and memory impairment induced by scopolamine in mice. The toxicity of CTX was measured in acute toxicity test. The analgesic effect of CTX in mice was measured by hot plate method and acetic aicd writhing test.
The ameliorating effect of CTX on learning and memory impairment induced by scopolamine in mice was studied by Y-Maze, Shuttle-box, Step-down and Water Maze methods respectively. LD₅₀ value of CTX was 2.17 mg/kg. CTX ip 0.03 mg/kg, 0. O6mg/kg significantly prolonged the latency time of mice to hot plate stimuli, attenuated the writhing times induced by acetic aicd. CTX ip 0.06 mg/kg, 0.12mg/kg significantly reduced the errors of the mice in Y-Maze test, decreased the mices training times, shorten the escape latency in Shuttle box test. In Step-down test, CTX ip 0.06mg/kg, 0.12mg/kg increased the escape latency and reduced the number of errors, CTX also reduced the searching platform latency and swim path-length in Morris water maze test with mice. All of the effects are dose-dependent. The results above suggested that CTX has an effect of analgesia and is able to improve the learning and memory impairment induced by scopolarnine in mice.

Key words: mice, analgesia, learning and memory, cobra cardiotoxin, mice, analgesia, learning and memory