Acute effects of a possible sialogogue, anethole trithione, in rat parotid glands

The present study examines the mechanism(s) of action of anethole trithione compared to the sialogogue pilocarpine. This was done by comparing the acute effects of these drugs on autonomic receptor binding (homogenates) together with parallel tests evaluating the biological activities of the receptor systems in collagenase-isolated rat parotid acini. The responses were measured as receptor-activated changes in cyclic nucleotide formation and acinar oxygen consumption. The results revealed that anethole trithione was unable to bind to muscarinic acetylcholine receptors and unable to stimulate the dynamic processes directly. It did, however, inhibit part (about 50%) of the carbachol-induced cyclic guanosine 3',5'-monophosphate (cyclic GMP) formation and O2 uptake. Furthermore, anethole trithione (greater than 1 microM) displaced [3H]prazosin (but not [3H]dihydroalprenolol ([3H]DHA] binding, without any effect upon the adrenaline-induced cyclic adenosine 3',5'-monophosphate (cyclic AMP) formation and O2 uptake. In conclusion, this study has shown that anethole trithione is not to be considered as a simple cholinergic agonist like pilocarpine, and further elucidation of the mechanism(s) of action of this agent would be useful.