title: Continuous stress promotes expression of VGF in melanotroph via suppression of dopamine.
abstract: Prolonged exposure to stress elicits profound effects on homeostasis that may lead to cryptogenic disorders such as chronic fatigue syndrome. To investigate the pathophysiology associated with the syndrome, we used a rat continuous stress (CS) model where the pituitary represents one of the most affected organs. Here we found that mRNA for VGF (non-acronymic), a member of the granin family, was induced specifically in the intermediate lobe (IL). This was matched by a concomitant increase at the peptide/protein level assessed by C-terminal antibody. Furthermore, the up-regulation of VGF was confirmed by immunohistochemistry in a subset of melanotrophs. VGF expression was altered in the IL of rats receivingthe dopamine D2 receptor agonist bromocriptine or the antagonist sulpiride. In vitro, dopamine dose-dependently decreased the mRNA levels in cultured melanotrophs. These findings suggest that VGF expression under CS is negatively regulated by dopaminergic neurons projecting from the hypothalamus.
authors.affiliation: Department of Functional Anatomy and Neuroscience, Nagoya University, Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan.
authors.forename: Kyohei
authors.initials: K
authors.lastname: Tokizane
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Konishi
authors.forename: Masaya
authors.initials: M
authors.lastname: Yasui
authors.forename: Tokiko
authors.initials: T
authors.lastname: Ogawa
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sasaki
authors.forename: Naoto
authors.initials: N
authors.lastname: Minamino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kiyama
mesh_terms: D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D002478:Cells, Cultured; D004298:Dopamine / Q000502:physiology*; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D059290:Dopaminergic Neurons / Q000378:metabolism; D015870:Gene Expression; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D008297:Male; D052717:Melanotrophs / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism; D052716:Pituitary Gland, Intermediate / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D061251:Primary Cell Culture; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013312:Stress, Physiological; D013469:Sulpiride / Q000494:pharmacology; D015533:Transcriptional Activation
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D009479:Neuropeptides; D012333:RNA, Messenger; C062040:Vgf protein, rat; D001971:Bromocriptine; D013469:Sulpiride; D004298:Dopamine