MOLECULAR AND CLINICAL EVIDENCE THAT DOPAMINERGIC RECEPTORS INFLUENCE SALIVARY SECRETION
H. Bagheri, D. O’Connell*, C. Damase-Michel, M. Lapeyre-Mestres, F. Gourio, S. Cismundo, J.M. Senard, O. Rascol, J.L. Montastruc.
Laboratoire de Pharmacologie Médicale et Clinique, INSERM U317, Faculté de Médecine, Toulouse, France.
*Departments of Pharmacology, Therapeutics and Medecine, Cork University Hospital, Ireland.
Dopamine (DA) has been shown to modulate salivary secretion in a number of vertebrate and invertebrate species. In rat salivary tissue, DA increases the volume and protein content of parotid and submandibular gland secretions in a dose-dependent manner acting predominantly on acinar cells at low doses and granular tubular cells at higner doses. Furthermore, patients with Parkinson disease frequently complain of feeling of increased salivary secretion. However, this observation and its mechanism remain discussed (excessive production of saliva, swallowing difficulties or both could explain this symptom).
Molecular and immunohistochemical studies revealed the presence of DAI like receptors in rat and human salivary tissue predominantly located within intralobular ducts.
Through a prospective clinical study, we have investigated the salivary secretion of Parkinsonian out-patients. 17.9% of patients were at stage 1, 14.9% at stage 2, 43.3% at stage 3 and 23.9% at stage 4. Sex ratio was 1.76 and mean age was 66.2±1.1 years (range: 34-85). These patients were matched to a control population. Patients or controls treated with anticholinergic drugs were excluded. Salivary secretion was measured using one salivary coKon plug weighed before and 2 minutes after it was placed under the tongue, close to internal gum. Statistical analysis by Kruskal-Wallis test showed a lower salivary flow in Parkinsonian group (mean: 502.7±39.9 mg) compared to control group (mean: 802.0±71.0 mg) (p