title: Dual adrenergic control of in vivo choline levels in the mouse major salivary glands.
abstract: 1. The purpose of this study was to demonstrate that the adrenergic nervous system regulates the in vivo choline levels in the mouse major salivary glands. 2. Methoxamine (alpha1-adrenoceptor agonist, 2.5-20 mg kg-1, s.c.) elevated choline levels dose-dependently and the effect of methoxamine (10 mg kg-1) was completely inhibited by the alpha-adrenoceptor antagonist phentolamine (5 mg kg-1, i.p.) but not by the beta-adrenoceptor antagonist propranolol (3 mg kg-1, i.p.). 3. In contrast, isoprenaline (beta-adrenoceptor agonist 0.25-20 mg kg-1, s.c.) lowered choline levels and the effect of isoprenaline (2 mg kg-1) was inhibited by propranolol, but not by phentolamine. 4 Noradrenaline (1-4 mg kg-1, s.c.) manifested both the alpha- and beta-adrenergic actions depending on its dose. Noradrenaline at 1-2 mg kg-1, lowered choline levels and the effect of noradrenaline (1 mg kg-1) was inhibited by propranolol, but not by phentolamine. On the other hand, noradrenaline (4 mg kg-1) elevated choline levels and the effect was blocked by phentolamine, but not by propranolol. 5. Tyramine (5-80 mg kg-1, s.c.) elicited the release of noradrenaline from sympathetic nerve terminals and induced essentially the same effects on the choline levels as noradrenaline. Tyramine (10 mg kg-1) lowered choline levels and the effect was inhibited by propranolol, but not by phentolamine. However, tyramine (80 mg kg-1) elevated choline levels and the effect was inhibited by phentolamine, but not by propranolol. 6. These results suggest that choline levels in the salivary glands may be under separate alpha- and beta-adrenergic control and suggest a possibility that the neurotransmitter noradrenaline released for sympathetic nerve terminals can manage the dual control of choline levels in some autonomic organs in a characteristic dose-dependent manner.
authors.affiliation: Department of Pharmacology, School of Dentistry, Iwate Medical University, Morioka 020-8505, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Murai
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: R
authors.initials: R
authors.lastname: Shirato
authors.forename: T
authors.initials: T
authors.lastname: Kawaguchi
mesh_terms: D000322:Adrenergic Agonists / Q000494:pharmacology*; D018674:Adrenergic Antagonists / Q000494:pharmacology*; D000818:Animals; D002794:Choline / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D008297:Male; D051379:Mice; D011941:Receptors, Adrenergic / Q000502:physiology*; D012469:Salivary Glands / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000322:Adrenergic Agonists; D018674:Adrenergic Antagonists; D011941:Receptors, Adrenergic; D002794:Choline