Intracerebroventricular chloride infusion enhances water intake in rats

Central anionic influences on dipsogenic response was studied in 54 euhydrated rats. Quantity of water consumed following third ventricular infusions of equimolar hypertonic chloride and bicarbonate solutions of sodium, potassium, calcium, and barium was compared. Control group (n=6) was given artificial cerebrospinal fluid infusion while rats of the remaining 8 groups (n=6 each) received one of the test solutions. All the chloride solutions, irrespective of the cations to which they were associated, elicited significantly greater dipsogenic response as compared to the control, or the bicarbonate solutions. Response of the bicarbonate solutions was more than the control only in the observation taken 30 min after the infusions. In the later observations, there was no significant difference. Drinking was not affected significantly by the cationic composition of the infusion fluids. Anionic concentration of the solutions has predominantly influenced the dipsogenic response. Enhancement of drinking following infusions of chloride solutions suggests the possibility of the CSF anions exerting active physiological influences over the juxtacerebroventricular sensors.