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Neonatal citalopram treatment inhibits the 5-HT depleting effects of MDMA exposure in rats.

Division of Neurology, Dept. of Pediatrics, Cincinnati Children's Research Foundation and University of Cincinnati College of Medicine, Cincinnati, OH 45229-3039, USA.
ACS Chemical Neuroscience (Impact Factor: 4.21). 01/2012; 3(1):12-21. DOI: 10.1021/cn2000553
Source: PubMed

ABSTRACT Neonatal exposure to 3,4-methylenedioxymethamphetamine (MDMA) produces long-term learning and memory deficits and increased anxiety-like behavior. The mechanism underlying these behavioral changes is unknown but we hypothesized that it involves perturbations to the serotonergic system as this is the principle mode of action of MDMA in the adult brain. During development 5-HT is a neurotrophic factor involved in neurogenesis, synaptogenesis, migration, and target region specification. We have previously showed that MDMA exposure (4×10 mg/kg/day) from P11-20 (analogous to human third trimester exposure) induces ~50% decreases in hippocampal 5-HT throughout treatment. To determine whether MDMA-induced 5-HT changes are determinative, we tested if these changes could be prevented by treatment with a selective serotonin reuptake inhibitor (citalopram: CIT). In a series of experiments we evaluated the effects of different doses and dose regimens of CIT on MDMA-induced 5-HT depletions in three brain regions (hippocampus, entorhinal cortex, and neostriatum) at three time-points (P12, P16, P21) during the treatment interval (P11-20) known to induce behavioral alterations when animals are tested as adults. We found that 5 mg/kg CIT administered twice daily significantly attenuated MDMA-induced 5-HT depletions in all three regions at all three ages but that the protection was not complete at all ages. Striatal dopamine was unaffected. We also found increases in hippocampal NGF and plasma corticosterone following MDMA treatment on P16 and P21, respectively. No changes in BDNF were observed. CIT treatment may be a useful means of interfering with MDMA-induced 5-HT reductions and thus permit tests of the hypothesis that the drug's cognitive and/or anxiety effects are mediated through early disruptions to 5-HT dependent developmental processes.

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    ABSTRACT: We previously showed that developmental 3,4-methylenedioxymethamphetamine (MDMA) treatment induces long-term spatial and egocentric learning and memory deficits and serotonin (5-HT) reductions. During brain development, 5-HT is a neurotrophic factor influencing neurogenesis, synaptogenesis, migration, and target field organization. MDMA (10 mg/kg × 4/d at 2 h intervals) given on post-natal day (PD) 11-20 in rats (a period of limbic system development that approximates human third trimester brain development) induces 50% reductions in 5-HT during treatment and 20% reductions when assessed as adults. To determine whether the 5-HT reduction is responsible for the cognitive deficits, we used citalopram (Cit) pretreatment to inhibit the effects of MDMA on 5-HT reuptake in a companion study. Cit attenuated MDMA-induced 5-HT reductions by 50% (Schaefer et al., 2012). Here we tested whether Cit (5 or 7.5 mg/kg × 2/d) pretreatment attenuates the cognitive effects of MDMA. Within each litter, different offspring were treated on PD11-20 with saline (Sal) + MDMA, Cit + MDMA, Cit + Sal or Sal + Sal. Neither spatial nor egocentric learning/memory was improved by Cit pretreatment. Unexpectedly, Cit + Sal (at both doses) produced spatial and egocentric learning deficits as severe as those caused by Sal + MDMA. These are the first data showing cognitive deficits resulting from developmental exposure to a selective serotonin reuptake inhibitor. These data indicate the need for further research on the long-term safety of antidepressants during pregnancy.
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