Terminations of LHRH-immunoreactive fibers in the subfornical organ of the opossum: an ultrastructural study.

Electron microscopic immunocytochemical approaches were used to analyze LHRH-containing elements in the subfornical organ of the opossum, a species in which this input to the subfornical organ is prominent. Not only were LHRH synaptic specializations easily demonstrated in the subfornical organ, forming axo-dendritic and axo-axonal contacts, but also LHRH-immunoreactive fibers contacted astrocytic end-feet on fenestrated capillaries and were found in the subependymal layer. LHRH-carrying elements in the subfornical organ may be important for relating reproductive functions to body fluid balance.