Ultrastructural localization of orexin-1 receptor in pre- and post-synaptic neurons in the rat arcuate nucleus

Neurosci Lett. 2002 Aug 30;329(2):209-12. doi: 10.1016/s0304-3940(02)00660-2.


The distribution and ultrastructural localization of the orexin-1 receptor (OX(1)R) in the rat arcuate nucleus were studied using immunocytochemical techniques. OX(1)R-containing neurons were found throughout the nucleus, but were concentrated in its posterior region. Both OX(1)R-positive perikarya and dendrites were found to receive synapses from other unknown axon terminals. In addition, a small number of OX(1)R-positive axon terminals were observed. These OX(1)R-immunoreactive axon terminals were often found to make synapses on unidentified immunonegative dendritic processes. The present results indicate that orexin may act on food intake regulating neurons through both pre- and post-synaptic OX(1)R.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arcuate Nucleus of Hypothalamus / chemistry
  • Arcuate Nucleus of Hypothalamus / ultrastructure*
  • Male
  • Neurons / chemistry
  • Neurons / ultrastructure*
  • Orexin Receptors
  • Presynaptic Terminals / chemistry
  • Presynaptic Terminals / ultrastructure*
  • Rats
  • Rats, Wistar
  • Receptors, G-Protein-Coupled
  • Receptors, Neuropeptide / analysis
  • Receptors, Neuropeptide / ultrastructure*


  • Orexin Receptors
  • Receptors, G-Protein-Coupled
  • Receptors, Neuropeptide