Atrial natriuretic peptide inhibits the spontaneous contractions of rabbit isolated ileum.
The present study investigates the effects of atriopeptin II on spontaneous phasic contractions of rabbit isolated ileum. Atriopeptin II caused a significant and concentration-dependent decrease in ileum motor activity. This effect was mimicked by 8-Br-cGMP and it was not affected by pretreatment with tetrodotoxin. Verapamil significantly decreased ileum contractions; however, in the presence of this calcium blocker, atriopeptin II further reduced ileal motility. These findings demonstrate that atriopeptin II depresses the motility of rabbit ileum through a cGMP-dependent mechanism and suggest that neither ileal neural networks nor extracellular calcium are involved in this effect.
Institute of Medical Pharmacology, School of Medicine and Dentistry, University of Pisa, Italy.
C
C
Blandizzi
C
C
Agen
G
G
Natale
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M
Del Tacca
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007082:Ileum / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010446:Peptide Fragments; D011817:Rabbits
D010446:Peptide Fragments; D009320:Atrial Natriuretic Factor; C062524:atrial natriuretic factor prohormone (103-125)