title: Pharmacological modulation of fluid secretion in the pigmented rabbit conjunctiva.
abstract: We determined net fluid secretion rate across the pigmented rabbit conjunctiva in the presence and absence of pharmacological agents known to affect active Cl- secretion and Na+ absorption. Fluid flow across a freshly excised pigmented rabbit conjunctiva mounted between two Lucite half chambers was measured by a pair of capacitance probes in an enclosed cabinet maintained at 37 degrees C and a relative humidity of 70%. Fluid transport was also measured in the presence of compounds known to affect active Cl- secretion (cAMP, UTP, and ouabain), Na+ absorption (D-glucose), or under the Cl--free condition on both sides of the tissue. Net fluid secretion rate across the pigmented rabbit conjunctiva in the serosal-to-mucosal direction at baseline was 4.3+/-0.2 microl/hr/cm2 (mean +/- s.e.m.). Net fluid secretion rate was increased approximately two-fold by mucosally applied 1 mM 8-Br cAMP (8.4+/-0.4 microl/hr/cm2) and 10 microM UTP (9.8+/-0.6 microl/hr/cm2), but was abolished by either serosally applied 0.5 mM ouabain (0.3+/-0.1 microl/hr/cm2) or under the Cl--free conditions (0.06+/-0.04 microl/hr/cm2). Mucosal addition of 20 mM D-glucose decreased net fluid secretion rate to 1.0+/-0.5 microl/hr/cm2. In conclusion, the pigmented rabbit conjunctiva appears to secrete fluid secondary to active Cl- secretion. This net fluid secretion is subject to modulation by changes in active Cl- secretion rate and in mucosal fluid composition such as glucose concentration.
authors.affiliation: Department of Pharmaceutical Sciences, University of Southern California, Los Angeles 90033, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Shiue
authors.forename: A A
authors.initials: AA
authors.lastname: Kulkarni
authors.forename: H J
authors.initials: HJ
authors.lastname: Gukasyan
authors.forename: J B
authors.initials: JB
authors.lastname: Swisher
authors.forename: K J
authors.initials: KJ
authors.lastname: Kim
authors.forename: V H
authors.initials: VH
authors.lastname: Lee
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001826:Body Fluids / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D003228:Conjunctiva / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology; D008297:Male; D011817:Rabbits; D014544:Uridine Triphosphate / Q000494:pharmacology
chemical_list: D002712:Chlorides; D015124:8-Bromo Cyclic Adenosine Monophosphate; D005947:Glucose; D014544:Uridine Triphosphate