Effects of partial locus coeruleus denervation and chronic mild stress on behaviour and monoamine neurochemistry in the rat.
It has been proposed that lesions of the ascending noradrenergic projections render animals more vulnerable to stress. In this study, the effects of partial denervation of the locus coeruleus (LC) by DSP-4 (10 mg/kg) treatment, chronic mild stress (CMS) and their combination were examined. DSP-4 was administered to rats 1 week before the onset of CMS, which was applied for 5 weeks. In the forced swimming test, the immobility time was decreased by both DSP-4 and CMS. In the open field test, the number of defecations was increased after DSP-4 treatment plus CMS. Partial LC denervation decreased the levels of noradrenaline (NA) by 34%, increased NA turnover, and decreased the density of beta-adrenoceptors in the cerebral cortex. CMS decreased the binding affinity of beta-adrenoceptors, an effect not observed in the DSP-4 treated animals. In conclusion, 6 weeks after partial LC denervation NA turnover is increased in the cortex, and the effect of CMS on emotionality is enhanced.
Häidkind
Riina
R
Department of Psychology, University of Tartu, Centre of Behavioural and Health Sciences, Tiigi 78, EE-50410 Tartu, Estonia.
Eller
Marika
M
Harro
Maarike
M
Kask
Ants
A
Rinken
Ago
A
Oreland
Lars
L
Harro
Jaanus
J
D000704:Analysis of Variance; D000818:Animals; D001596:Benzylamines / Q000633:toxicity*; D015306:Biogenic Monoamines / Q000378:metabolism*; D001835:Body Weight / Q000187:drug effects; D002908:Chronic Disease; D003714:Denervation / Q000379:methods; D005106:Exploratory Behavior / Q000187:drug effects; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D008125:Locus Coeruleus / Q000187:drug effects*; D008297:Male; D014179:Neurotransmitter Uptake Inhibitors / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D011941:Receptors, Adrenergic / Q000145:classification / Q000187:drug effects / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism; D044263:Receptors, Serotonin, 5-HT1; D013312:Stress, Physiological / Q000378:metabolism / Q000523:psychology*; D013395:Sucrose / Q000378:metabolism
D001596:Benzylamines; D015306:Biogenic Monoamines; D014179:Neurotransmitter Uptake Inhibitors; D011941:Receptors, Adrenergic; D017448:Receptors, Dopamine D2; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D013395:Sucrose; C012102:DSP 4