title: Evidence that separate PGE2 receptors modulate water and sodium transport in rabbit cortical collecting duct.
abstract: Prostaglandin E2 (PGE2) modulates both water and sodium transport in the rabbit cortical collecting duct (CCD). To determine whether these effects are mediated by separate PGE2 receptors, we compared the effects of PGE2 and its analogue sulprostone in the isolated perfused rabbit CCD. PGE2 increased basal water permeability (hydraulic conductivity), whereas sulprostone did not. PGE2 and sulprostone were equipotent inhibitors of water absorption when it was prestimulated by vasopressin. Pertussis toxin completely reversed the inhibitory effect of sulprostone but only partially reversed the inhibitory effect of PGE2. In contrast, a protein kinase C (PKC) inhibitor, staurosporine, partially reversed the inhibitory effect of PGE2 but had no effect on sulprostone. PGE2 also raised intracellular calcium ([Ca2+]i). This effect is coupled to its capacity to inhibit Na+ absorption. Sulprostone was 10-fold less potent than PGE2 both in raising [Ca2+]i or inhibiting sodium transport. The results suggest sulprostone selectively interacts with a PGE2 receptor coupled to pertussis toxin-sensitive inhibition of water permeability. Sulprostone less potently activates a PGE2 receptor coupled to [Ca2+]i, PKC activation, and sodium transport and completely fails to interact with the PGE2 receptor that stimulates water permeability in the collecting duct. These results suggest distinct PGE2 receptors modulate sodium and water transport in the CCD.
authors.affiliation: Department of Medicine, University of Ottawa, Ontario, Canada.
authors.forename: R L
authors.initials: RL
authors.lastname: Hébert
authors.forename: H R
authors.initials: HR
authors.lastname: Jacobson
authors.forename: D
authors.initials: D
authors.lastname: Fredin
authors.forename: M D
authors.initials: MD
authors.lastname: Breyer
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001834:Body Water / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015232:Dinoprostone / Q000031:analogs & derivatives / Q000494:pharmacology*; D004533:Egtazic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000187:drug effects / Q000502:physiology*; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D010477:Perfusion; D037342:Pertussis Toxin; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011817:Rabbits; D018078:Receptors, Prostaglandin E / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000378:metabolism*; D019311:Staurosporine; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D018078:Receptors, Prostaglandin E; D010566:Virulence Factors, Bordetella; D001127:Arginine Vasopressin; C016767:sulprostone; D004533:Egtazic Acid; D012964:Sodium; D037342:Pertussis Toxin; D011493:Protein Kinase C; D019311:Staurosporine; D015232:Dinoprostone; D002118:Calcium