Effects of sympathetic nerve agonists/antagonists on salivary IgA secretion. (a) Salivary IgA concentrations after application of the sympathetic nervous system agonist (norepinephrine 1 mg/kg) and/or antagonist (prazosin 1 mg/kg, propranolol 1 mg/kg, or 10 mg/kg) with pilocarpine. “+” indicates the reagent that was mixed and administered to mice, “−” indicates the reagent that was not administered to mice. (b,c) Salivary IgA concentrations when the α receptor (phenylephrine, 5 mg/kg; the numbers in parentheses are the number of samples) (b) or β receptor (isoproterenol, 5 mg/kg; n = 4–5) (c) were stimulated at ZT6 or ZT18 (n = 3–5). Values were shown as means ± SEM. (a) ***p < 0.001, **p < 0.01, vs. the NE(+)-Prazosin(−)-Propranolol(−) group (one-way ANOVA with Tukey post-hoc test). (b) *p < 0.05, ZT18 group cont. vs. PE (Mann-Whitney test). (c) **p < 0.01, iso group ZT6 vs. ZT18 (Student’s t-test).