title: The paracellular component of water flow in the rat submandibular salivary gland.
abstract: 1. The pathway of water flow during salivary secretion by the isolated, perfused rat submandibular gland was examined using a family of homologous radiodextran molecules as probes of paracellular fluid transfer. 2. The secretion/perfusate ratio (S/P) of the secreted probes versus molecular radius during fluid secretion evoked by ACh could be resolved into two components: one that fitted a free-diffusion (Stokes-Einstein) curve and indicated diffusion through large channels, and a convective component that was linearly related to radius. 3. The convective component had a cut-off point at 0.5 nm (5 A) radius and an S/P intercept of near 1.0 at the radius of water, which indicates that most of the volume flow was paracellular. 4. The nature of such a paracellular flow is discussed together with the possible integration of this volume flow with the cellular transport of ions, resulting in an isotonic primary secretion from the gland.
authors.affiliation: Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki 444, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Murakami
authors.forename: B
authors.initials: B
authors.lastname: Shachar-Hill
authors.forename: M C
authors.initials: MC
authors.lastname: Steward
authors.forename: A E
authors.initials: AE
authors.lastname: Hill
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002199:Capillary Permeability; D004730:Endothelium, Vascular / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012463:Saliva / Q000378:metabolism; D013363:Submandibular Gland / Q000098:blood supply / Q000166:cytology / Q000378:metabolism*