Water versus NaCl intake by rats administered certain dipsogens acutely.
Isotonic saline was ingested in a greater volume than water when any one of three dipsogenic agents [L-5-hydroxytryptophan (25 mg/kg, SC), isoproterenol (25 micrograms/kg, SC), and angiotensin II (100 micrograms/kg, SC)] was administered acutely to rats given either isotonic saline or water to drink. These results are consistent with, but not exclusive to, the hypothesis that feedback inhibition of ingested isotonic saline on further fluid intake is less than that of water. Additional studies showed that the dipsogenic response to angiotensin II (200 micrograms/kg, SC) decreased as the concentration of NaCl solution offered to drink increased beyond 0.15 M in rats given either water or NaCl solution to drink. This suggests the possibility that the intensity of taste of the NaCl solutions may be a factor in their intake under these conditions, although the intake of these salt solutions by untreated controls did not reflect this. When the rats were allowed to choose between either 0.15 or 0.25 M NaCl solution and water, administration of angiotensin II (either 100 or 200 micrograms/kg, SC) increased water intake in preference to the NaCl solution. These results suggest that the rat, under these conditions, has a preference for water over NaCl solution.
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001066:Appetite / Q000187:drug effects*; D004327:Drinking Behavior / Q000187:drug effects*; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology*; D007552:Isotonic Solutions; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride; D014867:Water
D007552:Isotonic Solutions; D014867:Water; D000804:Angiotensin II; D012965:Sodium Chloride; D006916:5-Hydroxytryptophan; D007545:Isoproterenol