AMP-activated protein kinase (AMPK) plays a crucial role in both cellular and whole body energy homeostasis. Here we demonstrate that the muscarinic receptor agonist carbachol activates AMPKalpha1-containing complexes in the human SH-SY5Y cell line via a mechanism specific for the AMPK upstream kinase, CaMKKbeta. Activation of AMPK inhibits mRNA expression of the orexigenic neuropeptides AgRP and MCH but surprisingly has no effect on NPY mRNA, a neuropeptide previously shown to be regulated by AMPK. Rather than restoring mRNA levels to baseline, pharmacological inhibition of CaMKKbeta or AMPK greatly increases AgRP and MCH mRNA expression. These data support a hypothesis that modulating basal AMPK activity in the hypothalamus is essential for maintaining tight regulation of pathways contributing to food intake.