CIRCULATORY AND IONOREGULATORY EFFECTS OF ATRIAL-NATRIURETIC-PEPTIDE ON RAINBOW-TROUT (SALMO-GAIRDNERI RICHARDSON) FED NORMAL OR HIGH-LEVELS OF DIETARY SALT

Rainbow trout fed a normal salt diet (1.3% NaCl) or a high salt diet (12% NaCl for at least 6 months) were chronically cannulated in the dorsal aorta and received 10 μg kg-1 ANP (1-28 human, UBC-Bioproducts) infused over a 10 min period. This had an insignificant influence on sodium balance, blood electrolytes and branchial sodium fluxes. In fish given a normal diet, the blood pressure and heart rate were uninfluenced by ANP, but pulse pressure was reduced by on average 60% and in some cases was not evident at all. Blood pressure in the fish fed a high salt diet was significantly higher than in the control fish; this together with heart rate and pulse pressure was not affected by ANP administration. © 1990 Kugler Publications.