Stimulation of minor salivary glands by intraoral treatment with the cholinesterase inhibitor physostigmine in man

A large number of the population, especially the elderly, suffers from dry mouth. The aim of the present investigation was to stimulate the minor salivary glands by the topical application of the cholinesterase inhibitor physostigmine. In eight healthy subjects, 100 µl of the substance, in the concentration interval 2–8 mg/ml, was applied locally to the inside of the lower lip for 1 min. In a separate study comprising 12 dry-mouth patients, 10 ml of 0.4–1.6 mg/ml physostigmine was administered as a mouth rinse solution for 2 min. Secretion from the labial glands, assessed using the Periotron^® method, increased in a dose-dependent manner in response to physostigmine in both groups. Average peak secretion exceeded baseline by more than 50% throughout the 30- to 45-min observation period; from 1.71 to 2.62 µl cm⁻² min⁻¹ among the healthy subjects and from 1.17 to 1.84 µl cm⁻² min⁻¹ among the dry mouth patients. No systemic effects were registered as reflected by ECG, heart rate or blood pressure. It is assumed that intraorally applied physostigmine diffuses through the oral mucosa and acts by preserving acetylcholine released from the cholinergic, parasympathetic nerves that innervate the minor salivary glands. The topical application of physostigmine to the oral mucosa may, therefore, be an interesting approach for the treatment of dry mouth.