Possible involvement of the dopamine D2 receptors of ventromedial hypothalamus in the control of free- and scheduled-feeding and plasma ghrelin level in rat

Abstract

Abstract Objectives We investigated effect of the ventromedial hypothalamus (VMH) dopamine D2 receptor inhibition on food intake and plasma ghrelin following chronic free or scheduled meal with different caloric intakes. Methods Male Wistar rats (220–250 g) were fed diets containing free (control) or three scheduled diets of standard, restricted and high-fat for 1 month. The animals stereotaxically received an intra VMH single dose of sulpiride (0.005 µg)/or saline (0.5 µL) before meal time. Thirty minutes later, food intake and circulating ghrelin were measured. Results Sulpiride significantly reduced food intake and ghrelin concentration in freely fed and scheduled-standard diet (p<0.05), while increased food intake, with ghrelin level on fasted level in scheduled-restricted group (p<0.01) compared to control. Food intake and ghrelin concentration between scheduled-high fat and freely fed or scheduled-standard diets did not show significant changes. Conclusions The VMH D2 receptors are possibly involved in controlling scheduled eating behavior, depending on energy balance context.