Effects of norepinephrine applied to the lateral hypothalamus on schedule induced polydipsia.

Intrahypothalamic injections of 3 doses of norepinephrine were administered to rats under conditions of 80 percent body weight reduction (prepolydipsia), 80 percent body weight reduction (schedule induced polydipsia), and normal body weight (postpolydipsia). The only significant reduction in water intake occurred with the highest dose of norepinephrine, under the prepolydipsic condition. The fact that norepinephrine failed to block schedule induced polydipsia indicates that this behavior is regulated by a different biochemical system than that of deprivation induced drinking.