A study explores the roles of inhibitory and stimulatory neurons in the brain's hypothalamus in regulating food intake. Feeding has complex neural underpinnings, with ties to physiological, social, and emotional factors. The arcuate nucleus of the brain's hypothalamus contains anorexigenic neurons, which inhibit feeding, and orexigenic neurons, which promote feeding. However, how the activities of the two neuronal groups are balanced is unclear. Huda Akil and colleagues used optogenetic, transgenic, viral, and anatomical approaches to target specific neurons and observe the effects on feeding in mice. The authors found that activating anorexigenic neurons alone rapidly inhibited food consumption, even in mice that had undergone fasting. However, attempting feeding inhibition simultaneously with activation of a subset of orexigenic neurons led to an increase in feeding. Thus, the two neuronal populations are unevenly balanced, and the activation of feeding is dominant. Follow-up analyses revealed that the two neuronal systems connect to different brain regions during activation, and that orexigenic neurons engage the opioid reward system. Further, the opioid receptor antagonist naloxone blunted increases in food intake induced by neuronal activation. According to the authors, rather than trying to amplify the inhibition of food consumption, interventions to control feeding should focus on blocking the activation drive, with possible value in targeting opioid receptors.
Article #18-02237: "Uneven balance of power between hypothalamic peptidergic neurons in the control of feeding," by Qiang Wei et al.
MEDIA CONTACT: Huda Akil, University of Michigan, Ann Arbor, MI; tel: 734-763-3770; e-mail: <firstname.lastname@example.org>