This grant proposal is a request for an ADAMHA RSDA (Level II). Humans and other animals display seasonal changes in body weight. The environmental signal for this response and for seasonal reproduction cycles in some species is daylength change, the neuroendocrine transducer of which is the pineal gland and its hormone, melatonin (MEL). Furthermore, the duration is the critical feature of the nocturnal MEL secretion profile. Siberian hamsters will be studied, a species that exhibit dramatic seasonal fluctuations in body fat following exposure to short 'winter-like' photoperiods. The goal of this research is to identify the CNS target sites of MEL that trigger seasonal changes in body fat. The target sites of MEL will be identified by determining: 1) the localization of MEL binding in brain using autoradiography and examining environmental and hormonal influences on MEL binding (e.g., time-of-day, photoperiod, pinealectomy [PINX]), 2) whether lesions of MEL binding sites will eliminate short day-induced changes in body weight and fat, food intake and reproductive status, 3) whether lesions of MEL binding sites block short day responses by eliminating the reception of the short day MEL signal by giving PINX hamsters bearing lesions programmed subcutaneous (s.c.) MEL infusions that mimic the MEL signal associated with transfer to short days, 4) the neural input and output pathways of the target sites using new, highly sensitive anterograde and retrograde tracers, 5) whether short day responses elicited by programmed s.c. MEL infusions can be blocked by selective damage of fibers of passage or cell bodies with microknife cuts and neurotoxins, respectively, in PINX hamsters, 6) whether short day responses can be elicited by directly microinfusing MEL into the target sites in PINX hamsters, and 7) the neurochemical substrate that receives the MEL signal by immunocytochemical methods. These studies should identify the CNS site(s) responsible for the photoperiodic (MEL) control of several seasonal cycles and add to our understanding of how naturally-occurring changes in the environment can have dramatic effects on body fat. The acquisition of the neuroanatomical techniques will compliment the interdisciplinary research program of the Principal Investigator and create a unique research environment for examining brain/behavior/energy metabolism.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Scientist Development Award - Research (K02)
Project #
1K02MH000841-01
Application #
3070208
Study Section
Research Scientist Development Review Committee (MHK)
Project Start
1990-04-01
Project End
1995-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
1
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Georgia State University
Department
Type
Schools of Arts and Sciences
DUNS #
837322494
City
Atlanta
State
GA
Country
United States
Zip Code
30302
Day, Diane E; Mintz, Eric M; Bartness, Timothy J (2002) Diet choice exaggerates food hoarding, intake and pup survival across reproduction. Physiol Behav 75:143-57
Demas, Gregory E; Bowers, Robert R; Bartness, Timothy J et al. (2002) Photoperiodic regulation of gene expression in brown and white adipose tissue of Siberian hamsters (Phodopus sungorus). Am J Physiol Regul Integr Comp Physiol 282:R114-21
Demas, G E; Drazen, D L; Jasnow, A M et al. (2002) Sympathoadrenal system differentially affects photoperiodic changes in humoral immunity of Siberian hamsters (Phodopus sungorus). J Neuroendocrinol 14:29-35
Campbell, Patrick K; Waymire, Katrina G; Heier, Robb L et al. (2002) Mutation of a novel gene results in abnormal development of spermatid flagella, loss of intermale aggression and reduced body fat in mice. Genetics 162:307-20
Bartness, Timothy J; Demas, Gregory E; Song, C Kay (2002) Seasonal changes in adiposity: the roles of the photoperiod, melatonin and other hormones, and sympathetic nervous system. Exp Biol Med (Maywood) 227:363-76
Day, D E; Bartness, T J (2001) Effects of foraging effort on body fat and food hoarding in Siberian hamsters. J Exp Zool 289:162-71
Song, C K; Bartness, T J (2001) CNS sympathetic outflow neurons to white fat that express MEL receptors may mediate seasonal adiposity. Am J Physiol Regul Integr Comp Physiol 281:R666-72
Shi, H; Bartness, T J (2001) Neurochemical phenotype of sympathetic nervous system outflow from brain to white fat. Brain Res Bull 54:375-85
Demas, G E; Bartness, T J (2001) Novel method for localized, functional sympathetic nervous system denervation of peripheral tissue using guanethidine. J Neurosci Methods 112:21-8
Bartness, T J; Song, C K; Demas, G E (2001) SCN efferents to peripheral tissues: implications for biological rhythms. J Biol Rhythms 16:196-204

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