Hypothalamic dopaminergic D2/D3 receptors are involved in feeding behavior regulation

Abstract

Dopamine is a neurotransmitter strongly involved in the feeding behavior regulation. It has been reported that different dopamine receptor agonists inhibited voluntary food intake, nevertheless, dopamine depletion induced intense hypophagia. Current knowledge of D2 receptors and D3 mRNA expression in the paraventricular nucleus of the hypothalamus (PVN) suggests that D2-like receptors may be playing a main role in the dopaminergic feeding behavior regulation. The aim of the present study was to evaluate the effects of paraventricular D2/D3 receptor activation on food intake and behavioral satiety sequence (BSS) in rats. Male Wistar rats (220-240 g) were intra-PVN injected with D2/D3/D4 receptor agonists and/or antagonists, and food intake and BSS were evaluated during 2 hours (dark phase of light cycle). The obtained results showed that intra-PVN D2/D3 activation significantly decreased food intake without disrupting the BSS. The above results strongly suggest that hypothalamic dopamine induces inhibitory effects on food intake via D2/D3 receptors in the PVN.