In the brain, neighboring neurons are often phenotypically distinct and can subserve opposing physiological processes. For example, POMC- and NPY-expressing neurons form distinct neuronal subtypes within the arcuate nucleus and have opposite effects on hypothalamic control of appetite and body weight regulation. Interpretation of gene expression profiling of these neurons, which differentially respond to hormones and metabolic state, depends on the ability to selectively label, harvest and analyze a single neuronal subtype. We have developed an approach to label, harvest and analyze targeted neuronal subtypes in the brain. In this approach, target cells are either labeled by a neuronal tracer (see MacKenzie et al., 2003 SFN Annual Meeting) or are genetically labeled as in this study. POMC neurons were labeled by EGFP expressed by the POMC promoter in transgenic mice. Mice were perfused with 4% paraformaldehyde and cryosections prepared for LCM. EGFP-positive cells were identified by direct fluorescence and...