Stress, endogenous opioids and salt intake.
The effect of stress on NaCl intake was examined in mice given a choice of water and 1.5% NaCl to drink. Immobilization of mice for 15-min and 24-h food deprivation resulted in a 2.5- and 5-fold increases in NaCl intake, respectively, without affecting water intake. Naloxone treatment (0.01, 0.1 and 1.0 mg/kg) produced a dose-dependent decrease in the stress-induced NaCl intake, as did captopril treatment (5, 10 and 50 mg/kg). Intraventricular injection of angiotensin II in mice resulted in an increase in 1.5% NaCl intake, which was blocked by naloxone. Morphine (10 mg/kg) increased the preference of mice for a normally aversive 3.0% NaCl solution, but not for preferred, less concentrated, solutions of NaCl. The results suggest that both endogenous opioids and angiotensin II contribute to stress-induced NaCl intake, and that endogenous opioids may also mediate the increase in NaCl intake, observed with angiotensin II.
D000804:Angiotensin II / Q000008:administration & dosage / Q000037:antagonists & inhibitors; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D004326:Drinking / Q000187:drug effects*; D004723:Endorphins / Q000037:antagonists & inhibitors / Q000502:physiology*; D005508:Food Deprivation / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000503:physiopathology*
D004723:Endorphins; D012462:Saline Solution, Hypertonic; D000804:Angiotensin II; D009270:Naloxone; D012965:Sodium Chloride; D009020:Morphine; D002216:Captopril