A particular subset of neurons located in an enigmatic region of the hypothalamus plays a central role in regulating feeding and body weight in mice, a new study reveals. The results illuminate a previously unknown neural mechanism of feeding regulation and offer new perspectives on understanding changes in appetite.
Knowledge of the function of a region of the hypothalamus called the nucleus tuberalis lateralis, or NTL, is scarce, though scientists seek to better understand it as damage to this brain region in patients results in marked declines in appetite, and in rapid loss in body weight. To further explore any role the NTL may have in regulation of feeding and body weight, researchers observed the behavior of GABAnergic somatostatin (SST) neurons in the NTL using a mouse model.
The authors found that the SST neurons were activated by both hunger (following overnight food deprivation) and after administration of the hunger hormone, ghrelin. Selective activation and deactivation of the neurons, using both drugs and optogenetics, demonstrated that eating behavior could be controlled - activation increased eating behavior, while inhibition significantly reduced it via projections to the paraventricular nucleus and bed nucleus of the stria terminalis. Total elimination of the neurons altogether resulted in decreased daily food intake as well as reduced weight gain. According to the study's findings, SST neurons are required for controlling healthy eating and body weight.
In a related Perspective, it was noted that the results are highly relevant - efforts to affect body weight and other physiological impairments associated with aberrant feeding behaviors, like obesity or anorexia nervosa, have been futile. Despite the translational uncertainty between the neural circuitry of mice and humans, the results are novel and warrant further investigation.
Neural circuit controlling hunger identified!
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