Effect of morphine on urine output: possible role of atrial natriuretic factor

Abstract We examined the possible role of atrial natriuretic factor (ANF) in morphine-induced diuresis. Morphine (20 μg/20 μl) administered intracerebroventricularly (i.c.v.) in conscious, normally hydrated Sprague-Dawley rats significantly increased urine output from 0.22 ± 0.16 ml/h/rat to 2.07 ± 0.46 ml/h/rat, 3 h after injection. Morphine injection also significantly increased the plasma ANF level to a maximum of 364 ± 46 pg/ml compared to control animals (33 ± 7 pg/ml in which 20 μl of saline was injected i.c.v. (P