Fig. 4.

UCP2 in axonal mitochondria of the hypothalamus.A–G, Electron micrographs reveal the association of the UCP2 immunolabeling with mitochondria of different hypothalamic axons (arrows). Arrowheads in Dpoint to a symmetrical synapse established by a UCP2-immunoreactive axon terminal in the arcuate nucleus. In F, note the abundance of UCP2-labeled mitochondria in an axon of the internal layer of the median eminence, which is the neuronal link between the magnocellular, paraventricular, and supraoptic nuclei and the posterior lobe of the pituitary. G, A large axon terminal containing UCP2-labeled mitochondria (arrows) in the external layer of the median eminence is in direct apposition to a portal capillary (cap), which provides the humoral link between the hypothalamus and the anterior pituitary.Asterisks indicate mitochondria with no UCP2 immunolabeling. Note that synaptic vesicles seem to be devoid of UCP2 labeling. Scale bar, 1 μm.