Tarantula Toxin Structure And Function

The contraction of isolated guinea pig ileum induced by electrical stimulus can be inhibited by HWTX-I,a toxin purified from the Chinese bird spider Sclcnocosmia huwenn. While being blocked , the ileum has almost the same contracting amplitude at certain concentration of ACh as that before adding HWTX-I. Phcnlolamine can not change the inhibi t ton effect of HWTX-I on guinea pig ileum. So it seems that the inhibition effect of HWTX-I on guinea pig ileum might be due to blocking the releasing of ACh or affecting the process before the releasing of ACh.