EFFECTS OF WATER-DEPRIVATION AND MORPHINE ADMINISTRATION ON ATRIAL-NATRIURETIC-PEPTIDE MESSENGER-RNA LEVELS IN RAT AURICLES

We investigated the influences of two potent stimuli, water deprivation (5 days) and morphine administration (100 mg/kg), on the level of atrial natriuretic peptide (ANP) mRNA in the rat auricles. The ANP mRNA level was measured by Northern blot hybridization analysis. The plasma concentration of ANP decreased in water deprived rats, and the ANP mRNA levels in both auricles of these rats were lower than those of the control, particularly in the left auricle. Thirty minutes after the injection of morphine, the plasma concentration of ANP markedly increased, while morphine increased the right auricular ANP mRNA level 4 hr after the administration. These data suggest that these stimuli can change ANP gene expression in the auricles and that the changes are induced differentially in both auricles.