Distribution of orexin B and its relationship with GnRH in the pig hypothalamus.
Increasing evidence suggests that orexins--hypothalamic neuropeptides--act as neurotransmitters or neuromediators in the brain, regulating autonomic and neuroendocrine functions. Orexins are closely associated with gonadotropin-releasing hormone (GnRH) neurons in the preoptic area and alter luteinizing hormone (LH) release, suggesting that they regulate reproduction. Here, we investigated the distribution of orexin B (immunohistochemical technique) and the relationship between orexin B and GnRH containing fibres and neurons in the pig hypothalamus using double immunofluorescence and laser-scanning confocal microscopy. Orexin B immunoreactive neurons were mainly localized in the perifornical area (PeF), dorsomedial hypothalamic nucleus (DMH), zona incerta (ZI) and the posterior hypothalamic area (PH), with a sparser distribution in the preoptic and anterior hypothalamic area. Immunoreactive fibres were distributed throughout the central nervous system. Approximately 30% GnRH neurons were in close contact with orexin B immunoreactive fibres, among these approximately 6% of GnRH neurons co-localized with orexin B perikarya in the region between the caudal preoptic area and the anterior hypothalamic area. Orexin B may regulate reproduction by altering LH release in the hypothalamus.
Su
Juan
J
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China.
Lei
Zhihai
Z
Zhang
Wenlong
W
Ning
Hongmei
H
Ping
Jihui
J
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D000068797:Orexins; D013552:Swine / Q000502:physiology*
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D007987:Gonadotropin-Releasing Hormone