Increased neuropeptide Y concentrations in the lateral hypothalamic area of the rat after the onset of darkness: Possible relevance to the circadian periodicity of feeding behavior

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Life Sciences; (United States)

DOI:https://doi.org/10.1016/0024-3205(91)90608-E· OSTI ID:5272330

McKibbin, P E; Robers, P; Williams, G ^[1]

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1. Univ. of Liverpool (United Kingdom)

Neuropeptide Y (NPY) is a major hypothalamic peptide which powerfully stimulates feeding when injected into the hypothalamus and is implicated in circadian rhythmicity. To investigate whether NPY is involved in the increased feeding that follows the onset of darkness in rats, NPY levels were measured in discrete hypothalamic areas before and after darkness. Four groups of eight adult female Wistar rats were habituated to a 12:12 hour light:dark cycle, with food presented at the onset of darkness (19.00 hours). Seven hypothalamic regions were microdissected from slices of fresh brain and acid-extracted for radioimmunoassay of NPY. NPY levels ((fmol/{mu}g) protein) were significantly higher in the lateral hypothalamic area (LHA) of the dark-phase group in both studies. In the other six regions, NPY levels did not differ between light and dark phases. The LHA regulates the circadian rhythmicity of feeding and NPY injection here stimulates feeding. Alterations in NPY in the LHA around the onset of darkness may be related to the initiation of dark-phase feeding.

• OSTI ID: 5272330
• Journal Information: Life Sciences; (United States), Vol. 48:26; ISSN 0024-3205
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
HYPOTHALAMUS
RADIOIMMUNOASSAY
PEPTIDES
BIOSYNTHESIS
DAILY VARIATIONS
FOOD
RATS
VISIBLE RADIATION
ANIMALS
BIOASSAY
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DIAGNOSTIC TECHNIQUES
ELECTROMAGNETIC RADIATION
IMMUNOASSAY
IMMUNOLOGY
ISOTOPE APPLICATIONS
MAMMALS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIATIONS
RADIOASSAY
RADIOIMMUNODETECTION
RADIOIMMUNOLOGY
RODENTS
SYNTHESIS
TRACER TECHNIQUES
VARIATIONS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques