Characterization of mouse salivary polypeptide secretion after oral administration of pilocarpine

Mouse salivary secretion provoked by single or multiple oral administration s of the cholinergic agent pilocarpine was characterized. An accessory ad h oc device, manipulated by a single operator, was used to collect saliva fro m various mice simultaneously. A single challenge by pilocarpine in the ran ge 40-400 mug provoked a dose-dependent secretory response. The secretory r esponse lasted for about 40 minutes and was constituted by four clearly def ined stages, namely: lag (5-10 min), maximal flow (10 min), slowering (15-2 0 min) and postsecretory rest. In this response, usual parameters were: max imal flow rate, 30-40 mul/min; total volume of saliva, 250-350 mul/mouse an d total salivary protein, about 700 mug/mouse. Temporal desensitization of the secretory response was observed within the first hour following a singl e stimulation by pilocarpine. However, recurrent stimulations by this agoni st given at 24-h intervals produced an equally intense secretory response, thus suggesting resensitization during that period. The polypeptiile compos ition of salivas obtained from a number of mice after a first pilocarpine s timulation were undistinguishable from each other. That salivary polypeptid e pattern was also observed in a series of sal was obtained day by day from single animals stimulated at 24-h intervals by the agonist. Thus, both the characteristics of the secretory response as well as the polypeptide compo sition of mouse saliva after short-term or long-term challenges by pilocarp ine were found to be highly consistent. Accordingly, these studies open the possibility of accomplishing a systematic molecular typing of saliva from individual living mice either from natural populations or from mice subject ed to experimental laboratory conditions.