Anatomical relationships of monoaminergic and neuropeptide Y-containing fibres with luteinizing hormone-releasing hormone systems in the preoptic area of the sheep brain: immunohistochemical studies.
Immunohistochemical double-labellings of luteinizing hormone-releasing hormone and neuropeptide Y, serotonin, tyrosine hydroxylase and dopamine-beta-hydroxylase, were performed in the preoptic area at the level of the organum vasculosum laminae terminalis. The observed neuropeptide Y-, serotonin-, tyrosine hydroxylase- and dopamine-beta-hydroxylase-immunoreactive fibres presented large varicosities when they were found within close proximity to luteinizing hormone-releasing hormone-containing perikarya. The fact that neuropeptide Y- and dopamine-beta-hydroxylase-immunoreactive fibres exhibited the same morphological characteristics and the comparison of the distribution of these two fibre populations raised the possibility of the co-localization of neuropeptide Y and dopamine-beta-hydroxylase in the same fibres. Dopamine-beta-hydroxylase- and tyrosine hydroxylase-immunoreactive fibres were morphologically different, suggesting that both dopaminergic and noradrenergic fibres could contact luteinizing hormone-releasing hormone-containing perikarya. Serotonin-immunoreactive fibres were also found close to the perikarya and to the proximal dendrite of the luteinizing hormone-releasing hormone-containing neurons. This study showed only putative sites of interactions between chemically identified fibres and luteinizing hormone-releasing hormone-containing neurons. Further ultrastructural immunocytochemical investigations are needed to ascertain the existence of synaptic contacts.
Tillet
Y
Y
Laboratoire de Neuroendocrinologie, INRA, Nouzilly, France.
Caldani
M
M
Batailler
M
M
D000818:Animals; D015306:Biogenic Monoamines / Q000502:physiology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D009478:Neuropeptide Y / Q000502:physiology*; D009638:Norepinephrine / Q000378:metabolism; D011301:Preoptic Area / Q000166:cytology / Q000502:physiology*; D012756:Sheep; D013194:Staining and Labeling
D015306:Biogenic Monoamines; D009478:Neuropeptide Y; D007987:Gonadotropin-Releasing Hormone; D009638:Norepinephrine