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Updated: May 20, 2026

Murine Salivary Functional Assessment via Pilocarpine Stimulation Following Fractionated Radiation
Published on: May 4, 2018
Activation of central α2-adrenoceptors mediates salivary gland vasoconstriction
Thiago S Moreira1, Ana C Takakura2, José V Menani3
1Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, 05508-000, São Paulo, Brazil.
Objective:
Peripheral treatment with the cholinergic agonist pilocarpine increases salivary gland blood flow and induces intense salivation that is reduced by the central injection of moxonidine (α2-adrenoceptors/imidazoline agonist). In the present study, we investigated the effects of the intracerebroventricular (i.c.v.) injection of pilocarpine alone or combined with moxonidine also injected i.c.v. On submandibular/sublingual gland (SSG) vascular resistance. In addition, the effects of these treatments on arterial pressure, heart rate and on mesenteric and hindlimb vascular resistance were also tested.
Design:
Male Holtzman rats with stainless steel cannula implanted into lateral ventricle and anaesthetized with urethane+α-chloralose were used.
Results:
Pilocarpine (500nmol/1μl) injected i.c.v. Reduced SSG vascular resistance and increased arterial pressure, heart rate and mesenteric vascular resistance. Contrary to pilocarpine alone, the combination of moxonidine (20nmol/1μl) and pilocarpine injected i.c.v. Increased SSG vascular resistance, an effect abolished by the pre-treatment with the α2-adrenoceptor antagonist yohimbine (320nmol/2μl). The increase in arterial pressure, heart rate and mesenteric resistance was not modified by the combination of moxonidine and pilocarpine i.c.v.
Conclusion:
These results suggest that the activation of central α2-adrenoceptors may oppose to the effects of central cholinergic receptor activation in the SSG vascular resistance.
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