Effect of acute or repeated stress on behavior and brain norepinephrine system in Wistar-Kyoto (WKY) rats.
WKY rats develop more restraint-induced gastric ulcers and exhibit more depressive behavior compared to other rat strains. Exposure to novel stressors for 21 days exacerbates depressive behavior in WKY rats and alters beta-adrenoceptors (beta-ARs) and norepinephrine transporter (NET) sites in several limbic brain regions when compared to Sprague-Dawley rats. The present study examined whether these effects would be elaborated following an acute stressor and whether WKY rats would demonstrate adaptation after repeated stress. Rats were subjected to a 2-h supine restraint stress for either one or eight consecutive daily sessions. Open-field behavioral data were collected immediately after the daily stress sessions. Brains were sectioned for autoradiographic analysis of 125I-pindolol binding to beta-ARs and 3H-nisoxetine binding to NET sites in discrete brain regions. Acute 1-day stress resulted in a significant drop in body weight and an inhibition of behaviors in the open field. These effects were also sustained following 7 days of chronic restraint stress. In contrast, while acute stress had no effect on NET binding sites or beta-ARs, repeated stress decreased NET sites in the amygdala, hypothalamus, and locus coeruleus with little effect on beta-ARs in the brain regions examined.
Zafar
H M
HM
Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Paré
W P
WP
Tejani-Butt
S M
SM
D000208:Acute Disease; D000319:Adrenergic beta-Antagonists / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001345:Autoradiography; D001522:Behavior, Animal / Q000502:physiology; D002908:Chronic Disease; D005473:Fluoxetine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D007457:Iodine Radioisotopes; D008032:Limbic System / Q000502:physiology*; D008297:Male; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000502:physiology*; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000503:physiopathology*; D014316:Tritium
D000319:Adrenergic beta-Antagonists; D007457:Iodine Radioisotopes; D005473:Fluoxetine; D014316:Tritium; C011386:nisoxetine; C029247:3-iodopindolol; D010869:Pindolol; D009638:Norepinephrine