Hyperdipsia in the baboon during operant conditioning of blood pressure elevation

Water intake was monitored in 7 male baboons during acquisition stages of blood pressure conditioning (Exp I) and during 24-hr periods (Exp II). Water intake was elevated during noncontingent food pellet delivery, and more so during early acquisition stages of operantly conditioned blood pressure elevations. Changes in blood pressure, heart rate, and water intake were found to correspond closely during conditioning sessions. Several possible sources of control over drinking are discussed, such as food-related discriminative stimuli and hypothalamic integration of cardiovascular hemodynamics, water ingestion, and thermal regulation. Data are thought to be best accounted for by the explanation that drinking is controlled by both external conditional and reinforcing stimuli and internal physiological influences. (40 ref)