Effect of scorpion toxin on gastric histamine and acetylcholine content in the rat.

1. The effects of a purified scorpion toxin (obtained from the Tityus serrulatus venom) on gastric secretion and on histamine and acetylcholine (ACh) levels were studied in rats. 2. Intravenous injection of 0.25 mg/kg of scorpion toxin induced a marked increase in gastric secretion in anesthetized rats. 3. Scorpion toxin also increased the histamine content in both the glandular and membranous portions of gastric wall, but there was no change in ACh content. 4. Incubation of slices of gastric wall with scorpion toxin induced a release of ACh from glandular and membranous portions. No effect of the toxin was observed on tissue-bound ACh or on free and tissue-bound histamine of either portion of the gastric wall. 5. We conclude that the gastric secretion evoked by intravenous injection of scorpion toxin in the rat is due, at least in part, to release of ACh and histamine. It is suggested that the toxin also induces synthesis of both ACh and histamine in the gastric wall.