Double labeling of dopamine and POMC neurons. Representative dopamine (A, B) and POMC (C, D) neurons that responded to estrogen. Arcuate neurons were filled with biocytin during the whole-cell recording. A, Biocytin-streptavidin-Cy2 labeling of fusiform arcuate neuron. Scale bar, 20 μm. B, Immunocytochemical staining of TH in the same neuron (arrow). C, Biocytin-streptavidin-Cy2 labeling of a small pyramidal arcuate neuron. Scale bar, 20 μm. D, Immunocytochemical staining of β-endorphin in the same neuron (arrow).