[Effect of toxic components of snake venoms on binding of substance P with rat brain membranes].

Ion-exchange HPLC is used for purification of the snake venom alpha-neurotoxins, chi-bungarotoxin, cytotoxins, and phospholipases A2. Among these purified polypeptides, phospholipases A2 are found to be the most potent in inhibiting the substance P binding to rat brain membranes, Ki approximately 10(-8) M. Other toxins are weak inhibitors (Ki greater than or equal to 10(-4)-10(-5) M), earlier data on the inhibiting activity of alpha-bungarotoxin being caused by the commercial preparations' contamination with phospholipase A2.