These studies were designed to examine the effects of "hunger" induced by food deprivation, 2-deoxy-D-glucose (200 mg/kg), or insulin (2 U/kg) and "thirst" induced by water deprivation, sodium chloride (4 M), or polyethylene glycol (5 ml of 30% w/w) on lateral hypothalamic self-stimulation in 40 male Long-Evans rats. Changes in self-stimulation were evaluated at electrodes that produced stimulation-bound eating and/or drinking or neither behavior. Daily 30-min test sessions consisted of three 5-min periods of self-stimulation alternated with three 5-min periods when bar presses resulted in a 5-s time-out from experimenter-delivered stimulation (stimulation escape). Food deprivation significantly increased self-stimulation; insulin, 2-deoxy-D-glucose, and sodium chloride significantly suppressed self-stimulation; water deprivation mildly inhibited self-stimulation; and polyethylene glycol had no effect. This pattern of findings was noted at electrodes that did and those that did not elicit eating and/or drinking. These findings argue against the hypothesis that the magnitude of lateral hypothalamic self-stimulation is differentially and predictably controlled by specific drive mechanisms indexed by the consummatory behaviors also elicited by the stimulation.
Animals Brain Mapping