Differential long-term effects of MDMA on the serotoninergic system and hippocampal cell proliferation in 5-HTT knock-out vs- wild-type mice-

Authors
T. Renoir, E. Païzanis, M. El Yacoubi, F. Saurini, N. Hanoun et al.


Lab
INSERM, U677, Paris, France ; Université Pierre et Marie Curie – Paris 6, Faculté de Médecine Pierre et Marie Curie, UMR S677, Paris, France.

Journal
The International Journal of Neuropsychopharmacology

Abstract
Although numerous studies investigated the mechanisms underlying 3,4-methylenedioxymethamphetamine (MDMA)-induced neurotoxicity, little is known about its long-term functional consequences on 5-HT neurotransmission in mice. This led us to evaluate the delayed effects of MDMA exposure on the 5-HT system, using in-vitro and in-vivo approaches in both 5-HTT wild-type and knock-out mice. Acute MDMA in-vitro application on slices of the dorsal raphe nucleus (DRN) induced concentration-dependent 5-HT release and 5-HT cell firing inhibition. Four weeks after MDMA administration (20 mg/kg b.i.d for 4 d), a 2-fold increase in the potency of the 5-HT1A receptor agonist ipsapirone to inhibit the discharge of DRN 5-HT neurons and a larger hypothermic response to 8-OH-DPAT were observed in MDMA- compared to saline-treated mice. This adaptive 5-HT1A autoreceptor supersensitivity was associated with decreases in 5-HT levels but no changes of [3H]citalopram binding in brain. Long-term MDMA treatment also induced a 30% decrease in BrdU labelling of proliferating hippocampal cells and an increased immobility duration in the forced swim test suggesting a depressive-like behaviour induced by MDMA treatment. All these effects were abolished in 5-HTT_/_ knock-out mice. These data indicated that, in mice, MDMA administration induced a delayed adaptive supersensitivity of 5-HT1A autoreceptors in the DRN, a deficit in hippocampal cell proliferation and a depressive-like behaviour. These 5-HTT-dependent effects, opposite to those of antidepressants, might contribute to MDMA-induced mood disorders.

BIOSEB Instruments Used:
Tail Suspension Test - Wireless (BIO-TST5)

DEMANDE DE PUBLICATION

Merci de votre intérêt pour notre gamme de produits et de votre demande pour cette publication qui vous sera envoyée si l'équipe de recherche et la revue le permettent. Notre équipe commerciale vous contactera dans les plus brefs délais.