title: Luminal vasopressin modulates transport in the rabbit cortical collecting duct.
abstract: We explored the action of luminal AVP in rabbit CCD perfused in vitro at 37 degrees C. Nanomolar concentrations of luminal AVP induced a sustained hyperpolarization of transepithelial voltage (Vt) in contrast to a transient hyperpolarization caused by basolateral AVP. 10 microM basolateral ouabain abolished the latter but not the former change in Vt. Despite a sustained hyperpolarization (from -20.7 +/- 2.9 to -34.1 +/- 4.7 mV; P less than 0.01), 10 nM luminal AVP only slightly altered net Na+ and K+ fluxes (7.6% stimulation and no significant change, respectively). Instead, luminal AVP appeared to modulate an acetazolamide-sensitive electrogenic ion transport because 200 microM basolateral acetazolamide suppressed the luminal AVP-induced hyperpolarization (percentage of Vt from -50.4 +/- 10.8 to -5.1 +/- 1.4; P less than 0.005). In terms of water transport, 10 nM luminal AVP did not change hydraulic conductivity (Lp, x 10(-7) cm/atm per s) (from 3.9 +/- 0.8 to 5.0 +/- 1.2), but suppressed the increase in Lp induced by 20 pM basolateral AVP (134.9 +/- 19.2 vs. 204.3 +/- 21.1 in control; P less than 0.05). These findings demonstrate distinct luminal action of AVP, suggesting amphilateral regulation of epithelial transport by AVP in the CCD.
authors.affiliation: Division of Nephrology, Jichi Medical School Hospital, Tochigi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ando
authors.forename: K
authors.initials: K
authors.lastname: Tabei
authors.forename: Y
authors.initials: Y
authors.lastname: Asano
mesh_terms: D000042:Absorption; D000086:Acetazolamide / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology* / Q000502:physiology; D001464:Barium / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D005934:Glucagon / Q000494:pharmacology; D066298:In Vitro Techniques; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism
chemical_list: D001127:Arginine Vasopressin; D001464:Barium; D005934:Glucagon; D012964:Sodium; D000086:Acetazolamide; D011188:Potassium