Orexinergic innervation of POMC-containing neurons in the rat arcuate nucleus

A pre-embedding double immunostaining technique was used to study the synap tic relationships between orexin-like immunoreactive axon terminals and pre opiomelanocortin (POMC)like immunoreactive neurons in the rat arcuate nucle us. Most of the synapses were axo-dendritic, while some axo-somatic synapse s were also found. Both the axo-somatic and axodendritic synapses were symm etrical. In some cases the presynaptic orexin-like immunoreactive axon term inals contained a few large dense-cored vesicles. The results suggest that the orexinergic axon terminals in the arcuate nucleus may play an important role in the regulation of food intake via synapses through POMC neurons. N euroReport 12:547-551 (C) 2001 Lippincott Williams & Wilkins.