The paraventricular nucleus (PVN) of the hypothalamus plays key roles in the regulation of energy balance. However, whether excitatory glutamatergic transmission from pro-opiomelanocortin (POMC) neurons affects the activity of PVN parvocellular neurons is not known. Mechanistic target of rapamycin complex 1 (mTORC1) controls intracellular energy availability. Cannabinoid receptor type 1 (CB1R) can affect the mTOR pathway. Mazier et al. show that mTORC1 activity in POMC neurons regulates glutamatergic inputs to PVN parvocellular neurons and that this function is exerted via control of pre-synaptic CB1R.