Neuropeptide Y innervation of ACTH-immunoreactive neurons in the arcuate nucleus of rats: a correlated light and electron microscopic double immunolabeling study

Brain Res. 1990 Jan 8;506(2):215-22. doi: 10.1016/0006-8993(90)91253-d.


A fairly high number of neuropeptide Y (NPY) and adrenocorticotropic hormone (ACTH) immunoreactive (ir) neuronal perikarya and dense networks of NPY-ir fibers are present in the hypothalamic arcuate nucleus of rats. Light and electron microscopic double immunolabeling techniques were used to demonstrate morphological connections between NPY-ir nerve fibers and ACTH-ir neurons here. Silver-gold intensified diaminobenzidine (DAB) labeling of perikaryal-dendritic immunoreactivity followed by a second, non-intensified DAB chromogen labeling of immunoreactive nerve terminals was used and recommended in the above sequence as a method of choice for the detection of synaptic contacts with double-labeling technique. By this way, NPY-immunoreactivity was localized in axons and axonal terminals forming a variety of conventional synaptic contacts with ACTH-ir neuronal perikarya and dendrites in the arcuate nucleus.

MeSH terms

  • Adrenocorticotropic Hormone / metabolism*
  • Animals
  • Arcuate Nucleus of Hypothalamus / cytology
  • Arcuate Nucleus of Hypothalamus / metabolism*
  • Immunohistochemistry
  • Male
  • Microscopy, Electron
  • Neuropeptide Y / metabolism*
  • Rats
  • Rats, Inbred Strains


  • Neuropeptide Y
  • Adrenocorticotropic Hormone