ATP stimulates appetite by enhancing the expression of hypothalamic orexigenic neuropeptides.

Hypothalamic neuropeptides play a pivotal role in regulating appetite and energy homeostasis. Extracellular ATP, a key signaling molecule in the hypothalamus, is associated with neuronal activity and metabolic processes. However, its role in appetite control remains unclear. This study explored how sustained extracellular ATP regulates the expression of hypothalamic orexigenic neuropeptides Agrp and Npy. The administration of ATP alone reduced food intake, body weight, and orexigenic neuropeptide expression in mice. Conversely, inhibition of ATP conversion into AMP using the ectonucleoside triphosphate diphosphohydrolase inhibitor ARL67156 caused a transient increase in these parameters. Prolonged extracellular ATP was shown to upregulate Agrp and Npy expression via purinergic P2X4 receptor (P2X4R) activation in AGRP/NPY-expressing cells. Activation of P2X4R induced CaMKII phosphorylation, which subsequently led to CREB phosphorylation and upregulation of orexigenic neuropeptides. Our findings reveal a mechanism whereby extracellular ATP accumulation promotes appetite through P2X4R-CaMKII-CREB signaling, shedding light on how extracellular ATP impacts hypothalamic appetite control.