Suprachiasmatic nucleus in the mouse: retinal innervation, intrinsic organization and efferent projections

Brain Res. 2001 Oct 19;916(1-2):172-91. doi: 10.1016/s0006-8993(01)02890-6.


The suprachiasmatic nucleus (SCN) is the principal circadian pacemaker of the mammalian circadian timing system. The SCN is composed of two anatomically and functionally distinct subdivisions, designated core and shell, which can be distinguished on the basis of their chemoarchitecture and connections in the rat. In the present study, we examine the intrinsic organization and the afferent and efferent connections of the mouse SCN using immunocytochemistry and ocular injections of cholera toxin. Neurons of the SCN shell contain GABA, calbindin (CALB), arginine vasopressin (AVP), angiotensin II (AII) and met-enkephalin (mENK), and receive input from galanin (GAL) and vasoactive intestinal polypeptide (VIP) immunoreactive fibers. Neurons of the SCN core synthesize GABA, CALB, VIP, calretinin (CALR), gastrin releasing peptide (GRP), and neurotensin (NT), and receive input from the retina and from fibers that contain neuropeptide Y (NPY) and 5-hydroxytryptamine (5HT). Fibers projecting from SCN neurons that are immunoreactive for AVP and VIP exhibit a characteristic morphology, and project to the lateral septum, a series of medial hypothalamic areas extending from the preoptic to the posterior hypothalamic area and to the paraventricular thalamic nucleus. The organization of the mouse SCN, and its connections, are similar to that in other mammalian species.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Angiotensin II / metabolism
  • Animals
  • Arginine Vasopressin / metabolism
  • Biological Clocks / physiology*
  • Calcium-Binding Proteins / metabolism
  • Cholera Toxin
  • Dopamine beta-Hydroxylase / metabolism
  • Enkephalin, Methionine / metabolism
  • Galanin / metabolism
  • Gastrin-Releasing Peptide / metabolism
  • Immunohistochemistry
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neural Pathways / cytology*
  • Neural Pathways / metabolism
  • Neurons / cytology*
  • Neurons / metabolism
  • Neuropeptide Y / metabolism
  • Neuropeptides / metabolism*
  • Neurotensin / metabolism
  • Neurotransmitter Agents / metabolism*
  • Phenotype
  • Retina / cytology*
  • Retina / metabolism
  • Serotonin / metabolism
  • Somatostatin / metabolism
  • Substance P / metabolism
  • Suprachiasmatic Nucleus / cytology*
  • Suprachiasmatic Nucleus / metabolism
  • Vasoactive Intestinal Peptide / metabolism
  • gamma-Aminobutyric Acid / metabolism


  • Calcium-Binding Proteins
  • Neuropeptide Y
  • Neuropeptides
  • Neurotransmitter Agents
  • Angiotensin II
  • Arginine Vasopressin
  • Serotonin
  • Substance P
  • Vasoactive Intestinal Peptide
  • Neurotensin
  • Somatostatin
  • gamma-Aminobutyric Acid
  • Enkephalin, Methionine
  • Gastrin-Releasing Peptide
  • Galanin
  • Cholera Toxin
  • Dopamine beta-Hydroxylase