Eating induced rise in LHA-dopamine correlates with meal size in normal and bulbectomized rats.

Dopaminergic function in the lateral hypothalamic area (LHA) is important for processing intrinsic and extrinsic feeding related information. Brain microdialysis was used to examine if dopamine release in the LHA correlates with meal size in normal and bulbectomized rats. Food-deprived bulbectomized rats ate significantly less food (1.7 +/- 0.1 g) than food-deprived sham operated rats (3.1 +/- 0.5 g, p < 0.05), accompanied by a lesser increase in LHA-dopamine release (150.6 +/- 4.9% vs. 195.1 +/- 13.9, p < 0.02). LHA-dopamine release was significantly higher in rats which ate a full meal (2.9 +/- 0.1 g) than in rats which ate half a meal (1.5 +/- 0.1 g, p < 0.05), being 155.9 +/- 7.8% vs. 131.0 +/- 4.9% (p < 0.05) in food-deprived normal rats. Data suggest that dopamine release in the LHA correlates to the quantity of food consumed during a meal.