Ecstasy induces apoptosis via 5-HT(2A)-receptor stimulation in cortical neurons.

REQUIMTE, Toxicology Department, Faculty of Pharmacy, University of Porto, Rua Aníbal Cunha 164, 4099/030 Porto, Portugal.
NeuroToxicology (Impact Factor: 3.05). 08/2007; 28(4):868-75. DOI: 10.1016/j.neuro.2007.04.005
Source: PubMed

ABSTRACT 3,4-Methylenedioxymethamphetamine (MDMA or "Ecstasy") is a psychoactive and hallucinogenic drug of abuse. MDMA has been shown to produce neurotoxicity both in animals and humans. MDMA and other amphetamines induce serotonergic and dopaminergic terminal neurotoxicity and also neurodegeneration in areas including the cortex, hippocampus, striatum and thalamus. Herein, we investigated the mechanisms involved in MDMA-induced neurotoxicity to neuronal serum free cultures from rat cortex. The hyperthermic effect produced by MDMA has been shown to be a clinically relevant aspect for the neurotoxic events. Thus, MDMA-induced toxicity to cortical neurons was evaluated both under normothermic (36.5 degrees C) and hyperthermic (40 degrees C) conditions. Our findings showed that MDMA produced neuronal apoptosis, accompanied by activation of caspase 3, in a concentration dependent manner. MDMA neurotoxicity was completely prevented by pre-treatment with a 5-HT(2A)-receptor antibody, which acted as an "irreversible non-competitive antagonist" of this receptor. Furthermore, MDMA depleted intracellular glutathione (GSH) levels in a concentration dependent manner, an effect that was attenuated by Ketanserin, a competitive 5-HT(2A)-receptor antagonist. Accordingly, N-acetylcysteine, an antioxidant and GSH precursor, also reduced MDMA-induced toxicity. Specific inhibitors of the inducible and neuronal nitric oxide synthase (NOS) partially prevented MDMA neurotoxicity, ascertaining the involvement of reactive nitrogen species, in the toxic effect. In conclusion, direct MDMA 5-HT(2A)-receptor stimulation produces intracellular oxidative stress that leads to neuronal apoptosis accompanied by caspase 3 activation.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Amphetamine-like psychostimulants (ATS) are used worldwide by millions of patients for several psychiatric disorders. Amphetamine (AMPH) and "ecstasy" (3,4-methylenedioxymethamphetamine or MDMA) are common drugs of abuse. The impact of chronic ATS exposure to neurons and brain aging is still undisclosed. Current neuronal culture paradigms are designed to access acute ATS toxicity. We report for the first time a model of chronic exposure to AMPH and MDMA using long-term rat cortical cultures. In two paradigms, amphetamines were applied to neurons at day one in vitro (DIV) (0, 1, 10 and 100 μM of each drug) up to 28 days (200 μM was applied to cultures up to 14DIV). Our reincubation protocol assured no decrease in the neuronal mediums' drug concentration. Chronic exposure of neurons to concentrations equal to or above 100 μM of ATS up to 28DIV promoted significant mitochondrial dysfunction and elicited neuronal death, which was not prevented by glutamate receptor antagonists at 14DIV. Amphetamines failed to promote accelerated senescence as no increase in β-galactosidase activity at 21DIV was found. In younger cultures (4 or 8DIV), AMPH promoted mitochondrial dysfunction and neuronal death earlier than MDMA. Overall, AMPH proved more toxic and was the only drug that decreased intraneuronal glutathione levels. Meanwhile, caspase 3 activity increased for either drug at 200 μM in younger cultures at 8DIV, but not at 14DIV. At 8DIV, ATS promoted a significant change in the percentage of neurons and astroglia present in culture, promoting a global decrease in the number of both cells. Importantly, concentrations equal to or below 10 μM of either drug did not promote neuronal death or oxidative stress. Our paradigm of neuronal cultures long-term exposure to low micromolar concentrations of amphetamines closely reproduces the in vivo scenario, being valuable to study the chronic impact of ATS.
    Neuroscience 07/2014; · 3.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 3,4- Methylenedioxymethamphetamine (MDMA or "Ecstasy") is a psychoactive and hallucinogenic drug of abuse. MDMA has been shown to produce neurotoxicity both in animals and humans. Recently, the vasodilator drugs such as pentoxifylline is one of the new strategies which have been considered as neuroprotector. In this study effect of pentoxifylline on bcl- 2 gene expression changes in hippocampus of rat following long- term use of ecstasy was investigated. 30 male Wistar rats weighing 250-300 g were randomly divided into 5 groups: control (normal), sham (MDMA injection), experimental 1 (MDMA and then PTX injections), experimental 2 (PTX injection and after 1 week, MDMA injection) and vehicle (saline injection) groups. All drugs were injected intraperitoneally.Two weeks later, the hippocampi were removed for studying the changes in bcl-2 gene expression. We used quantitative real time PCR for detection of bcl-2 gene expression in treated groups and then compared them to control samples. The results showed the gene dosage ratio of 0.49, 0.78 and 1.17 for sham, experimental 1 and experimental 2 groups, respectively. The results also showed the bcl-2 gene expression declined in sham group as compared to the experimentalgroups. Furthermore, we observed a significant difference in the bcl-2 gene expression between sham and experimental 2 groups. We conclude that quantitative real time PCR could be used as a direct method for the detection of bcl-2 gene expression in tested and normal samples.
    Iranian journal of pharmaceutical research (IJPR) 01/2013; 12(3):521-7. · 0.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Methamphetamine is a psychomotor stimulant that produces hyperlocomotion in rodents. Limonene (a cyclic terpene from citrus essential oils) has been reported to induce sedative effects. In this study, we demonstrated that limonene administration significantly inhibited serotonin (5-hydroxytryptamine, 5-HT)-induced head twitch response in mice. In rats, pretreatment with limonene decreased hyperlocomotion induced by methamphetamine injection. In addition, limonene reversed the increase in dopamine levels in the nucleus accumbens of rats given methamphetamine. These results suggest that limonene may inhibit stimulant-induced behavioral changes via regulating dopamine levels and 5-HT receptor function.
    Phytomedicine: international journal of phytotherapy and phytopharmacology 01/2014; · 2.97 Impact Factor