Figure 5. Model of the control of body temperature and appetite by VMPO^LPS neurons.

Activation of the immune system in periphery leads to circulating immune signals. These signals activate ependymal and endothelial cells lining the blood brain barrier, which react by secreting additional signals including IL-1b, PGE2 and CCL2, which are further amplified by local glial cells. VMPO^LPS neurons are activated by these signals through their expression of the corresponding receptors as well as through activation of local synaptic inputs. In response, VMPO^LPS neurons induce fever, warmth seeking and loss of appetite through direct and indirect connections to homeostatic brain circuits.