Suppressed neuropeptide Y (NPY) mRNA in rat amygdala following restraint stress.
We have previously demonstrated that NPY produces anxiolytic-like effects through actions in the amygdala, and that anxiogenic-like effects of restraint stress are mediated through this structure. Here, we examined the effects of restraint stress on NPY mRNA levels in amygdala and several other brain regions. A sensitive solution hybridization-RNase protection assay (RPA) was developed, employing a combination of internal and external standards, which allowed absolute quantitation of NPY mRNA in tissue-samples of less than 10 mg. NPY mRNA levels were determined, following a 1-h restraint stress, in homogenates of tissue from the amygdala, neocortex, striatum and hypothalamus, and the time course of these effects was examined. A highly significant decrease in NPY-mRNA levels was seen in the amygdala at 1 h and 2 h following restraint, with levels returning to normal within 10 h. A similar effect was seen in the neocortex, but was less pronounced and slower in onset. Striatal and hypothalamic NPY expression was not significantly affected. Tissue levels of NPY-peptide were modestly decreased in the amygdala at 1 h following restraint and had returned to normal within 4 h. The present findings support the hypothesis that anxiety related behavioral effects of stress may in part be mediated through modulation of NPY function in the amygdala.
Thorsell
A
A
Department of Clinical Neuroscience and Family Medicine, Karolinska Institute, Addiction Center South, M67 Huddinge University Hospital, Sweden.
Svensson
P
P
Wiklund
L
L
Sommer
W
W
Ekman
R
R
Heilig
M
M
D000679:Amygdala / Q000378:metabolism*; D000818:Animals; D016375:Antisense Elements (Genetics); D001007:Anxiety / Q000235:genetics / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D002940:Circadian Rhythm; D003342:Corpus Striatum / Q000378:metabolism; D015870:Gene Expression; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D015336:Molecular Probe Techniques; D009478:Neuropeptide Y / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012260:Ribonucleases; D013312:Stress, Physiological / Q000235:genetics* / Q000378:metabolism; D014018:Tissue Distribution
D016375:Antisense Elements (Genetics); D009478:Neuropeptide Y; D012333:RNA, Messenger; D012260:Ribonucleases