Atrial natriuretic factor potentiates glibenclamide-sensitive K+ currents via the activation of receptor guanylate cyclase in follicle-enclosed Xenopus oocytes.
The effect of the atrial natriuretic factor (ANF) on K+ channel opener-induced glibenclamide-sensitive K+ currents was studied using follicle-enclosed Xenopus oocytes. K+ currents induced by the K+ channel opener Y-26763 were potentiated by ANF (0.5-50 nM) in a concentration-dependent manner. 50 nM ANF increased the peak amplitude of the current by 59.4 +/- 9.9% (mean +/- S.E., n = 8). ANF (1-1000 nM) increased the cGMP contents of follicle-enclosed oocytes; about 13-fold increase was achieved by 100 nM ANF, showing a peak at 5 min. The ANF-stimulated accumulation of cGMP was suppressed by HS-142-1 (a non-peptide antagonist of the ANF receptor), at concentrations of 3-300 micrograms/ml. The K+ current-potentiating effect of ANF was mimicked by membrane-permeable cGMP (1 mM 8-bromo cGMP). These results suggest that ANF potentiates glibenclamide-sensitive K+ currents via the activation of receptor guanylate cyclase and consequent accumulation of cGMP in follicle-enclosed Xenopus oocytes.
Sakuta
H
H
Department of Pharmacology, National Defense Medical College, Saitama, Japan.
Okamoto
K
K
Tandai
M
M
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001578:Benzopyrans / Q000494:pharmacology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism*; D011134:Polysaccharides / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D014982:Xenopus laevis
D001578:Benzopyrans; C072551:HS 142-1; D011134:Polysaccharides; D015221:Potassium Channels; C016276:8-bromocyclic GMP; D009320:Atrial Natriuretic Factor; D006162:Guanylate Cyclase; D006152:Cyclic GMP; C074338:Y 26763; D005905:Glyburide