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κ‐Opioid‐receptor agonists modulate the renal excretion of water and electrolytes in anaesthetized rats
Author(s) -
Ashton N.,
Balment R.J.,
Blackburn T.P.
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb14674.x
Subject(s) - endocrinology , medicine , chemistry , diuresis , reabsorption , free water clearance , renal physiology , diuretic , renal sodium reabsorption , (+) naloxone , vasopressin , kidney , renal function , opioid , receptor
1 Subcutaneous injection of the κ‐opioid agonists U50,488 (10 mg kg −1 ) and tifluadom (3.5 mg kg −1 ) into Inactin‐anaesthetized, saline‐infused rats was associated with a diuresis, antinatriuresis and anti‐kaliuresis which lasted for up to 2h. A high (5 mg kg −1 ), but not low (0.1 mg kg −1 ), dose of naloxone blocked the renal effects of U50,488. 2 U50,488 administration in anaesthetized, vasopressin‐deficient Brattleboro DI rats was associated with an attenuated diuresis, though the antinatriuretic response remained intact. 3 The diuretic action of U50,488 was associated with an increase in glomerular filtration rate while fractional fluid reabsorption remained steady. In contrast, fractional sodium and potassium reabsorption were increased. 4 These data suggest that κ‐opioid agonists alter renal handling of both water and electrolytes. This appears to be mediated by two separate mechanisms: increased fluid loss largely reflects altered glomerular events while the fall in electrolyte excretion results from altered tubular handling.