[Effect of cGMP-dependent signaling system in regulation of osmotic permeability in the frog urinary bladder].
In frogs' isolated urinary bladders, contribution of cytosolic guanylate cyclase and cGMP-dependent protein kinase to regulation of osmotic permeability was studied. ODQ (25-100 microM), an inhibitor of cytosolic guanylate cyclase induced an increase of vasotocin-activated osmotic permeability but had no effect on the hormone-activated transepithelial urea transport. In isolated mucosal epithelial cells ODQ (50 microM) decreased the concentration of intracellular cGMP. In these cells L-NAME (0.5 nM), an inhibitor of NO synthase, also decreased the level of cGMP whereas cAMP was significantly increased. 8-pCPT-cGMP (25 and 50 microM), a permeable cGMP analogue which selectively activates protein kinase G, inhibited vasotocin-induced increase of water transport along osmotic gradient indicating that protein kinase G is involved in regulation of water reabsorption. The data obtained show that NO/cGMP signalling system in the frog urinary bladder appears to be a negative modulator of vasotocin-activated increase of osmotic permeability.
Fok
E M
EM
I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Acad. Sci., 194223, St. Petersburg, pr. M. Toreza, 44, Russia.
Lavrova
E A
EA
Bakhteeva
V T
VT
Parnova
R G
RG
D000818:Animals; D002463:Cell Membrane Permeability / Q000502:physiology*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000096:biosynthesis / Q000502:physiology*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D003600:Cytosol / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D066298:In Vitro Techniques; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011896:Rana temporaria; D015398:Signal Transduction / Q000502:physiology*; D014508:Urea / Q000493:pharmacokinetics; D001743:Urinary Bladder / Q000166:cytology / Q000378:metabolism / Q000502:physiology*
D004791:Enzyme Inhibitors; D014508:Urea; D019001:Nitric Oxide Synthase; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase; D006152:Cyclic GMP
Rol' tsGMF-zavisimoĭ signal'noĭ sistemy v reguliatsii osmoticheskoĭ pronitsaemosti mochevogo puzyria liagushki.