Pharmacological investigation of the role of ion channels in salivary secretion.

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The role of K+ and Cl- channels in salivary secretion was investigated, with emphasis on the potential role of Ca2+ -activated K+ channels. Ligand saturation kinetic assays and autoradiography showed large-conductance (BK) K+ channels to be highly expressed in rat submandibular and parotid glands, whereas low-conductance (SK) K+ channels could not be detected. To investigate the role of K+ and Cl- channels in secretion, intact rabbit submandibular glands were vascularly perfused and secretion induced by 10 microM ACh. Secretion was inhibited by 34+/-3% following perfusion with the general K+ channel inhibitor Ba2+ (5 mM), whereas organic inhibitors of BK (200 nM paxilline) or intermediate-conductance (IK) K+ channels (5 microM clotrimazole) had no effect. Secretion was strongly influenced by Cl- channel inhibitors, as 100 microM 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB) completely abolished, while 10 microM NPPB, 20 microM NS1652 and 20 microM NS3623 reduced secretion by 34+/-3%, 23+/-3% and 59+/-4%, respectively. In conclusion, although high expression levels of BK channels were demonstrated, pharmacological tools failed to demonstrate any role for BK, IK or SK channels in salivary secretion in the rabbit submandibular gland. Other types of K+ channel, however, and particularly Cl- channels, are essential for ACh-induced salivary secretion.
Original languageEnglish
JournalPflügers Archiv: European Journal of Physiology
Issue number1
Pages (from-to)78-87
Number of pages9
Publication statusPublished - 2003

Bibliographical note

Keywords: Acetylcholine; Animals; Autoradiography; Binding Sites; Chloride Channels; Female; Male; Parotid Gland; Peptides; Perfusion; Potassium Channel Blockers; Potassium Channels, Calcium-Activated; Rabbits; Rats; Rats, Wistar; Submandibular Gland

ID: 8419010