Temporal changes of c-fos expression in oxytocinergic magnocellular neuroendocrine cells of the rat hypothalamus with restraint stress.
The present experiments were undertaken to examine c-fos expression in magnocellular neuroendocrine cells (MNCs) of the rat hypothalamus with restraint stress using dual immunohistochemistry for c-fos and oxytocin. Restraint stress induced c-fos expression in oxytocinergic MNCs in the supraoptic nucleus (SON) and paraventricular nucleus (PVN). Quantitative immunohistochemical analysis revealed that percentages of c-fos-positive cells to oxytocin-immunoreactive MNCs in the SON and PVN maximally increased at 2 h after restraint stress had started, and began to decline in spite of the fact that the restraint of animals were continued. Similar results were obtained from time course of c-fos expression in parvocellular neurons of the PVN. When animals were released to move freely in their home cages following the 3-h restraint, the plasma levels of oxytocin declined to reach basal levels within 30 min and c-fos immunoreactivity in the hypothalamic MNCs and parvocellular neurons disappeared faster than those of the continually restrained. These results demonstrate that restraint stress induces c-fos expression in oxytocinergic MNCs in the SON and PVN, and that time course of c-fos expression is transient even in the continuation of restraint stress.
Miyata
S
S
Department of Applied Biology, Kyoto Institute of Technology, Japan.
Itoh
T
T
Lin
S H
SH
Ishiyama
M
M
Nakashima
T
T
Kiyohara
T
T
D000818:Animals; D015870:Gene Expression / Q000502:physiology*; D016762:Genes, fos / Q000502:physiology*; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D009490:Neurosecretory Systems / Q000166:cytology / Q000378:metabolism*; D010121:Oxytocin / Q000096:biosynthesis* / Q000097:blood; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000378:metabolism*
D016760:Proto-Oncogene Proteins c-fos; D010121:Oxytocin