Sex-dependent differences in the concentrations of the principal neurotransmitters, noradrenaline and acetylcholine, in the three major salivary glands of mice

The concentrations of principal neurotransmitters in the submandibular, parotid and sublingual glands were compared between two pairs of age-matched male and female ddY mice, one pair consisting of 4-week-old and the other 8-week-old animals. Sex-dependent differences in both noradrenaline and acetylcholine concentrations were observed only in the submandibular gland, although each neurotransmitter showed distinct features. The acetylcholine concentration in the submandibular gland was higher in the female at both ages, whereas the noradrenaline concentration was higher in the female at the age of 4 weeks but became higher in the male by the age of 8 weeks. On the other hand, the total amounts of noradrenaline and acetylcholine per submandibular gland were already greater in the male at 4 weeks, and the male parotid and sublingual glands also had a greater noradrenaline content by 4 weeks and 8 weeks, respectively. Each type of gland had similar growth rates over the 4-week period, and the male submandibular and parotid glands were heavier than the female. In addition, each type of gland had its characteristic ratio of noradrenaline to acetylcholine concentration, which did not differ between the sexes and remained in similar basic patterns during the period examined, except for the submandibular gland of 8-week-old male mice, which developed greater amounts of the sympathetic neurotransmitter noradrenaline.