TNF and obesity due to melanocortin 4 receptor deficiency: Thus, we first sought to examine NAc GPR120 expression and if GPR120 stimulation protects against the activation of NAc microglia in response to central of TNF-α and IL-1β—two cytokines required for the innate immune response, that influence affective states and that are upregulated in the brain in response to systemic LPS, stress and obesity [2, 29].