Atrial natriuretic peptide clearance receptors in trout: effects of receptor inhibition in vivo.
Inactivation of circulating atrial natriuretic peptides (ANP) by specialized clearance (C) receptors has been characterized in mammals but has not been examined in fish. In the present study arterial blood pressure, urine flow, and urine electrolytes were measured in chronically cannulated rainbow trout, Oncorhynchus mykiss, during infusion of the specific C receptor inhibitor, SC-46542. C receptor inhibition decreased blood pressure and pulse pressure, increased heart rate and urine flow, but did not affect urinary electrolyte concentrations. These responses are consistent with those produced by exogenous ANP administration and indicate that: (1) trout possess C-type receptors capable of ANP inactivation, and (2) ANP-like molecules are continuously released and metabolized by trout in vivo. Phosphoramidon, an inhibitor of neutral endopeptidase, did not enhance the SC-46542 response, indicating that C receptors predominate in ANP inactivation in these fish.
Duff
D W
DW
Department of Biology, Indiana University, South Bend, Indiana.
Olson
K R
KR
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism* / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D014337:Trout / Q000378:metabolism*; D014556:Urine
D010446:Peptide Fragments; D011956:Receptors, Cell Surface; C059320:SC 46542; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor