Refined salt appetite methodology for rats demonstrated by assessing sex differences.

The salt appetite of the rat is useful for studying certain behavioral and neurological functions. A refined method for inducing and measuring salt appetite for these purposes is described, and the efficiency and reliability of the procedures are demonstrated by parametric studies comparing the appetite behaviors of male and female rats. The method for inducing salt appetite couples 2 days of dietary sodium deprivation with a brief diuretic treatment. The measurement procedure involves a 2-hr period of access to one of several sodium chloride solutions differing in palatability or concentration. The induction procedure allowed precise control of drive levels, and the measurement procedure yielded highly reliable results as a function of the properties of the incentives. Female rats consistently ingested about twice as much sodium chloride solution as did male rats regardless of the palatability of the solution or of body sodium levels. At the same time, female rats lost less sodium in urine following diuretic treatment.