Effect of KCl and atropine on peroxidase secretion. (A) Lacrimal glands from 10- to 12-week old BALB/c mice were processed to measure peroxidase secretion, over a 20-minute period, in buffer containing increasing concentrations of KCl (5–90 mM). Peroxidase secretion is expressed as a percentage of the total. Data are means ± SEM, n = 3 to 7. *Significant difference from 5 mM KCl-induced peroxidase secretion. (B) Lacrimal gland lobules from 10- to 12-week-old BALB/c mice were preincubated for 10 minutes, with or without atropine (10−5 M). Lobules were then incubated, for 20 minutes, in buffer containing 5 mM KCl (spontaneous secretion) and 20 minutes in 75 mM KCl (evoked secretion). Peroxidase secretion is expressed as a percentage of the total. Data are means ± SEM, n = 3. *Significant difference from spontaneous peroxidase secretion and atropine alone. #Significant difference from evoked peroxidase secretion in the presence of atropine.