[Atrial natriuretic factor stimulates the frog urinary bladder osmotic permeability in presence of a cyclic nucleotide phosphodiesterase inhibitor].
The role of atrial natriuretic factor (ANF) in regulation of osmotic water permeability was studied in isolated frog Rana temporaria L. urinary bladder. It was found that ANF (rANF, 1-28) added to the serosal solution at concentrations 5 x 10(-8) M and higher dosedependently stimulated the arginine-vasotocin (AVT)-induced increase of osmotic water permeability. The effect of ANF was revealed only in presence of 3-isobuthyl-1-methylxantine (180 microM) and was accompanied by significant elevation of cGMP level in urinary bladder homogenate and isolated mucosal epithelial cells. C-ANF (des[Gln18, Ser19, Gly20, Leu21, Gly22]-ANF-(4-23)-NH2), a specific agonist of NPR-C receptor, exerted no effect on osmotic water permeability. ANF induced a significant increase of cAMP in urinary bladder homogenates (AVT, 5 x 10(-11) M: 52.3 +/- 10.6; AVT + ANF, 10(-7) M: 114.2 +/- 26.9 pmol/mg protein, n = 5, p < 0.05). The activity of adenylate cyclase in crude plasmatic membrane fraction was not changed. Milrinone, a specific inhibitor of phosphodiesterase 3, at concentrations from 25 to 80 microM, enhanced both the hydroosmotic response to AVT and AVT-stimulated cAMP production. Altogether these data demonstrate that, in the frog urinary bladder, ANF stimulates the AVT-induced increase of osmotic water permeability acting probably through NPR-A receptor-coupled mobilization of cGMP and cGMP-dependent inhibition of phosphodiesterase 3.
Parnova
R G
RG
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Acad. Sci., 44 M. Torez Av., St. Petersburg, 194223, Russia.
Lavrova
E A
EA
Bakhteeva
V T
VT
Fok
E M
EM
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D066298:In Vitro Techniques; D008297:Male; D009711:Nucleotides / Q000378:metabolism*; D009995:Osmosis; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D011896:Rana temporaria; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology; D019459:Urothelium / Q000378:metabolism; D014668:Vasotocin / Q000494:pharmacology
D009711:Nucleotides; D010726:Phosphodiesterase Inhibitors; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D006152:Cyclic GMP; D014668:Vasotocin