Secretion of the hypothalamic neuropeptide luteinizing hormone releasing hormone is critical to reproduction in all mammals. The neural afferents that modulate the activity of LHRH neurons are not known, although gonadal steroids and the catecholamines, especially norepinephrine, are potent stimulators of LHRH secretion. Activity of LHRH neurons may be modulated by neural systems either by direct innervation of LHRH neurosecretory cells or indirectly through interneurons. Nonetheless, these influences must ultimately reach LHRH neurons to influence synthesis and/or neurosecretion. It is the purpose of these studies to identify and morphologically characterize contacts that are afferent to those LHRH neurons that are critical to ovulation in mammals. First, it is hypothesized that there are groups of LHRH neuronal cell bodies that abruptly change their content of immunoreactive LHRH in relationship to ovulation, while other groups do not; and that these """"""""dynamic"""""""" and """"""""static"""""""" groups of cells are present within the forebrain of mammalian species that are spontaneous (monkeys and rats), induced (ferrets) or seasonal ovulators (bats). Second, it is hypothesized that synaptic input to """"""""dynamic"""""""" but not """"""""static"""""""" groups of LHRH neurons changes in relation to ovulation and/or development. Finally, it is hypothesized that among mammals exhibiting different mechanisms of ovulation, afferent contacts to those LHRH neurons that are critical to ovulation, will be morphologically similar; while afferents to other LHRH neurons, whose function is specifically related to the pattern of ovulation, will differ. Afferent synapses will be examined for their plasticity, and, regardless of the degree of plasticity, for morphological parameters in pre- and post- ovulatory females compared to that in prepuberal females and adult males. These studies will utilize light and electron microscopic immunocytochemistry to study relationships between LHRH neurons themselves, between LHRH neurons and catecholamine neurons and between LHRH neurons and other afferents of unspecified origin.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD019803-04A1
Application #
3317385
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1985-09-01
Project End
1992-11-30
Budget Start
1989-07-01
Budget End
1990-11-30
Support Year
4
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Tufts University
Department
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02111
King, J C; Liu, E; Ronsheim, P M et al. (1998) Expression of Fos within luteinizing hormone-releasing hormone neurons, in relation to the steroid-induced luteinizing hormone surge in guinea pigs. Biol Reprod 58:316-22
King, J C; Tai, D W; Hanna, I K et al. (1995) A subgroup of LHRH neurons in guinea pigs with progestin receptors is centrally positioned within the total population of LHRH neurons. Neuroendocrinology 61:265-75
King, J C; Rubin, B S (1995) Dynamic alterations in luteinizing hormone-releasing hormone (LHRH) neuronal cell bodies and terminals of adult rats. Cell Mol Neurobiol 15:89-106
King, J C; Rubin, B S (1994) Dynamic changes in LHRH neurovascular terminals with various endocrine conditions in adults. Horm Behav 28:349-56
Hiatt, E S; Brunetta, P G; Seiler, G R et al. (1992) Subgroups of luteinizing hormone-releasing hormone perikarya defined by computer analyses in the basal forebrain of intact female rats. Endocrinology 130:1030-43
Stopa, E G; Koh, E T; Svendsen, C N et al. (1991) Computer-assisted mapping of immunoreactive mammalian gonadotropin-releasing hormone in adult human basal forebrain and amygdala. Endocrinology 128:3199-207
Anthony, E L; Weston, P J; Montvilo, J A et al. (1989) Dynamic aspects of the LHRH system associated with ovulation in the little brown bat (Myotis lucifugus). J Reprod Fertil 87:671-86
Blaustein, J D; King, J C; Toft, D O et al. (1988) Immunocytochemical localization of estrogen-induced progestin receptors in guinea pig brain. Brain Res 474:1-15
Stopa, E G; Sower, S A; Svendsen, C N et al. (1988) Polygenic expression of gonadotropin-releasing hormone (GnRH) in human? Peptides 9:419-23
King, J C; Sower, S A; Anthony, E L (1988) Neuronal systems immunoreactive with antiserum to lamprey gonadotropin-releasing hormone in the brain of Petromyzon marinus. Cell Tissue Res 253:1-8

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