Effect of scorpion toxin (tityustoxin, TsTx) on the salivary gland of the rat, in vivo and in vitro

Intravenous injection of purified scorpion toxin (tityustoxin, TsTX) brings about the appearance of salivary flow and of kallikrein and amylase secretion in the saliva of rats. In experiments performed in vitro, using slices of parotid gland, a dose-response curve correlating tityustoxin concentration with kallikrein and amylase activities was obtained. The secretion of kallikrein is slower and smaller than that of amylase after up to 60 min of incubation. Experiments in which propranolol, phenoxybenzamine or atropine were injected into rats or added to parotid gland slices showed that the release of kallikrein is more dependent on cholinergic mechanisms, whereas the release of amylase is mainly related to adrenergic effects. Pre-treatment of the animals with reserpine confirms these results. The actions of tityustoxin on the kallikrein and amylase secretions, per min, are more effective than those by pilocarpine and isoproterenol, respectively.