title: Multiscale modelling of saliva secretion.
abstract: We review a multiscale model of saliva secretion, describing in brief how the model is constructed and what we have so far learned from it. The model begins at the level of inositol trisphosphate receptors (IPR), and proceeds through the cellular level (with a model of acinar cell calcium dynamics) to the multicellular level (with a model of the acinus), finally to a model of a saliva production unit that includes an acinus and associated duct. The model at the level of the entire salivary gland is not yet completed. Particular results from the model so far include (i) the importance of modal behaviour of IPR, (ii) the relative unimportance of Ca(2+) oscillation frequency as a controller of saliva secretion, (iii) the need for the periodic Ca(2+) waves to be as fast as possible in order to maximise water transport, (iv) the presence of functional K(+) channels in the apical membrane increases saliva secretion, (v) the relative unimportance of acinar spatial structure for isotonic water transport, (vi) the prediction that duct cells are highly depolarised, (vii) the prediction that the secondary saliva takes at least 1mm (from the acinus) to reach ionic equilibrium. We end with a brief discussion of future directions for the model, both in construction and in the study of scientific questions.
authors.affiliation: Department of Mathematics, University of Auckland, New Zealand. Electronic address: sneyd@math.auckland.ac.nz.
authors.forename: James
authors.initials: J
authors.lastname: Sneyd
authors.affiliation: Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Australia & NICTA Victoria Research Laboratory, Australia.
authors.forename: Edmund
authors.initials: E
authors.lastname: Crampin
authors.affiliation: Department of Pharmacology and Physiology, University of Rochester, USA.
authors.forename: David
authors.initials: D
authors.lastname: Yule
mesh_terms: D001692:Biological Transport; D008954:Models, Biological; D012463:Saliva / Q000378:metabolism*
keywords: Aquaporins; Calcium oscillations; Inositol trisphosphate; Salivary gland acinar cells; Sjögren’s syndrome; Water transport