title: Suppression of glucocorticoid secretion and antipsychotic drugs have similar effects on the mesolimbic dopaminergic transmission.
abstract: Specific antagonists of central dopaminergic receptors constitute the major class of antipsychotic drugs (APD). Two principal effects of APD are used as criteria for the pre-clinical screening of their antipsychotic action: (i) inhibition of basal and depolarization-induced activity of mesolimbic dopaminergic neurons; (ii) antagonism of the locomotor effects of dopaminergic agonists. Given that glucocorticoid hormones in animals increase dopamine release and dopamine-mediated behaviors and that high levels of glucocorticoids can induce psychotic symptoms in humans, these experiments examined whether inhibition of endogenous glucocorticoids might have APD-like effects on mesolimbic dopaminergic transmission in rats. It is shown that suppression of glucocorticoid secretion by adrenalectomy profoundly decreased (by greater than 50%): (i) basal dopaminergic release and the release of dopamine induced by a depolarizing stimulus such as morphine (2 mg/kg, s.c.), as measured in the nucleus accumbens of freely moving animals by microdialysis; (ii) the locomotor activity induced by the direct dopaminergic agonist apomorphine. The effects of adrenalectomy were glucocorticoid specific given that they were reversed by the administration of glucocorticoids at doses within the physiological range. Despite its profound diminution of dopaminergic neurotransmission, adrenalectomy neither modified the number of mesencephalic dopaminergic neurons nor induced gliosis in the mesencephalon or in the nucleus accumbens, as shown by tyrosine hydroxylase and glial fibrillary acidic protein immunostaining. In conclusion, these findings suggest that blockade of central effects of glucocorticoids might open new therapeutic strategies of behavioral disturbances.
authors.affiliation: Laboratoire de Psychobiologie des Comportements Adaptatifs, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 259, Université de Bordeaux II, France.
authors.forename: P V
authors.initials: PV
authors.lastname: Piazza
authors.forename: M
authors.initials: M
authors.lastname: Barrot
authors.forename: F
authors.initials: F
authors.lastname: Rougé-Pont
authors.forename: M
authors.initials: M
authors.lastname: Marinelli
authors.forename: S
authors.initials: S
authors.lastname: Maccari
authors.forename: D N
authors.initials: DN
authors.lastname: Abrous
authors.forename: H
authors.initials: H
authors.lastname: Simon
authors.forename: M
authors.initials: M
authors.lastname: Le Moal
mesh_terms: D000315:Adrenalectomy; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001058:Apomorphine / Q000494:pharmacology; D003345:Corticosterone / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D005938:Glucocorticoids / Q000502:physiology; D006801:Humans; D008032:Limbic System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
chemical_list: D014150:Antipsychotic Agents; D005904:Glial Fibrillary Acidic Protein; D005938:Glucocorticoids; D009020:Morphine; D014446:Tyrosine 3-Monooxygenase; D001058:Apomorphine; D004298:Dopamine; D003345:Corticosterone