Effects of GABA and Leptin Receptor‐Expressing Neurons in the Lateral Hypothalamus on Feeding, Locomotion, and Thermogenesis

Objective The lateral hypothalamus (LH) is known for its role in feeding, and it also regulates other aspects of energy homeostasis. How genetically defined LH neuronal subpopulations mediate LH effects on energy homeostasis remains poorly understood. The behavioral effects of chemogenetically activating LH gamma‐aminobutyric acid (GABA) and the more selective population of LH GABA neurons that coexpress the leptin receptor (LepR) were compared. Methods LepR‐cre and VGAT‐cre mice were injected with AAV5‐hSyn‐DIO‐hM3DGq‐mCherry in the LH. The behavioral effects of LH GABA or LH LepR neuronal activation on feeding, locomotion, thermogenesis, and body weight were assessed. Results The activation of LH GABA neurons increased body temperature (P ≤ 0.008) and decreased body weight (P ≤ 0.01) despite decreased locomotor activity (P = 0.03) and transiently increased chow intake (P ≤ 0.009). Also, similar to other studies, this study found that activation of LH GABA neurons induced gnawing on both food and nonfood (P = 0.001) items. Activation of LH LepR neurons decreased body weight (P ≤ 0.01) and chow intake when presented on the cage floor (P ≤ 0.04) but not when presented in the cage top and increased locomotor activity (P = 0.002) and body temperature (P = 0.03). Conclusions LH LepR neurons are a subset of LH GABA neurons, and LH LepR activation more specifically regulates energy homeostasis to promote a negative energy balance.