NMDA lesions of rat lateral hypothalamus: effects of dietary and physiological challenges.

Rats bearing NMDA lesions of the lateral hypothalamus (LH) were tested for their reactions to alterations in the sensory (but not calorific) content of the diet (finickiness), to 24 h food or water deprivation, and to dehydrating injections of hypertonic saline and glucoprivic injections of 2-deoxy-D-glucose (2-DG). Lesioned rats lost weight following surgery but had no significant eating or drinking difficulties in the home cage. They were not finicky and responded normally to 24 h food or water deprivation. Responses to hypertonic saline and 2-DG challenges were significantly impaired. These data suggest a subtle motivational disorder following LH lesion, rather than motor or sensory impairment.