Sodium ingestion in oxytocin knockout mice
Regis R Vollmer1, Xia Li, Joseph R Karam
1Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA. vollm@pitt.edu
Experimental Neurology
|August 26, 2006
Summary
Oxytocin (OT) pathways do not solely regulate NaCl intake in mice. Oxytocin knockout and wild-type mice showed similar responses to varying NaCl diets and dehydration, suggesting OT is more critical for short-term intake control.
Area of Science:
- Neuroscience
- Physiology
- Behavioral Science
Background:
- Central oxytocin (OT) pathways are known to inhibit NaCl intake in rodents under specific conditions.
- Oxytocin knockout (OT KO) mice previously consumed more saline than wild-type (WT) mice when water-deprived.
Purpose of the Study:
- To investigate the role of oxytocin in regulating NaCl intake in C57BL/6 mice across different conditions.
- To compare NaCl intake behaviors between OT KO and WT mice when presented with varying NaCl concentrations and diets.
Main Methods:
- Assessed taste aversion to different NaCl concentrations (0.2 M, 0.3 M, 0.5 M) in OT KO and WT mice.
- Measured daily intake of low (0.01%), regular (1.0%), and high (8.0%) NaCl diets with concurrent choice of water or 0.5 M NaCl.
- Evaluated responses to sustained dehydration using 0.5 M NaCl as the sole fluid source.
Main Results:
- OT KO and WT mice exhibited equivalent taste aversion to NaCl solutions, proportional to concentration.
- Both genotypes consumed similar amounts of NaCl diets and equally reduced saline intake as dietary NaCl increased.
- During dehydration, OT KO and WT mice showed comparable decreases in food intake, body weight, and increases in fluid ingestion.
Conclusions:
- Oxytocin pathways are not the sole regulators of ad libitum NaCl intake from solutions or diets.
- Oxytocin signaling appears more critical for modulating NaCl intake during brief periods of dehydration compensation.
