Reduced 5-hydroxytryptamine-dependent behaviour in rats following chronic corticosterone treatment
| Autor: | G.A. Kennett, Gerald Curzon, Stephen L. Dickinson |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Male
Restraint Physical Agonist Serotonin medicine.medical_specialty Dextroamphetamine Methoxydimethyltryptamines medicine.drug_class Open field chemistry.chemical_compound Dopamine Corticosterone Postsynaptic potential Internal medicine medicine Animals p-Chloroamphetamine Amphetamine P-Chloroamphetamine Molecular Biology Behavior Animal General Neuroscience Brain Rats Inbred Strains Rats Endocrinology chemistry Neurology (clinical) Stress Psychological Developmental Biology medicine.drug Faecal pellet |
| Zdroj: | Brain Research. 345:10-18 |
| ISSN: | 0006-8993 |
| Popis: | The effect of chronic corticosterone treatment (50 mg/kg s.c. 2 × daily) for up to 4 days on behavioural responses to drugs affecting 5-hydroxytryptamine (5-HT) and dopamine (DA) systems was examined in rats 20 h after the last treatment, when placed in experimental cages, to which they had become habituated. Corticosterone- and vehicle-treated rats exhibited both comparable spontaneous behaviour when given 0.9% NaCl i.p. and showed similar behavioural responses following amphetamine (3 mg/kg i.p.). However, responses to the 5-HT-releasing drugp-chloroamphetamine (PCA, 4 mg/kg i.p.) were altered with decreased head-weaving hind-limb abduction and forepaw treading. Postsynaptic changes appear to be involved as responses to the 5-HT agonist 5-methoxy-N, N-dimethyltryptamine (5-MeODMT, 5 mg/kg i.p.) (tremor, hind-limb abduction and forepaw treading) were also decreased. Hind brain and striatal concentrations of 5-HT, DA and their metabolites were comparable in corticosterone and vehicle treated rats killed 20 h after the last treatment. Brain PCA levels determined 30 min after injection were also comparable in both groups. PCA induced behaviour was not altered 20 h after 1 day corticosterone treatment or 4 day after 1 day treatment and 5-MeODMT-induced behaviour was not altered 20 h after 14 days treatment with a lower dose of corticosterone (10 mg/kg s.c. × 2). Twenty h after 1 day corticosterone treatment (50 mg/kg s.c. × 2), rats placed in an open field for the first time showed significantly more activity and dropped fewer faecal pellets than controls. However 20 h after 4 days treatment, activity in the open field was significantly less than that of controls. These effects of corticosterone were strikingly different and largely opposite to those of repeated immobilisation stress. They thus suggest that stress-induced corticosterone release may oppose some of the behavioural consequences of stress. |
| Databáze: | OpenAIRE |
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