Persistent MDMA‐induced dopaminergic neurotoxicity in the striatum and substantia nigra of mice

Repeated doses of MDMA (ecstasy) given to mice cause a lasting loss of dopamine-producing neurons in the substantia nigra, a brain region critical for movement. One day after injection, the number of these neurons drops and remains low for at least 30 days. In the striatum, markers of dopamine function also fall sharply within a day and stay reduced for a month, though some recovery begins after three days, with new nerve fiber growth. Damage is selective: the nucleus accumbens is unaffected, showing MDMA destroys the nigrostriatal pathway but spares the mesolimbic pathway. Immune cell activation follows the same pattern, confirming the link between inflammation and dopamine cell death.

Study at a glance

Abstract

Abstract Acute administration of repeated doses of 3,4‐methylenedioxymethamphetamine (MDMA, ecstasy) dramatically reduces striatal dopamine (DA) content, tyrosine hydroxylase (TH), and DA transporter‐immunoreactivity in mice. In this study, we show for the first time the spatiotemporal pattern of dopaminergic damage and related molecular events produced by MDMA administration in mice. Our results include the novel finding that MDMA produces a significant decrease in the number of TH‐immunoreactive neurons in the substantia nigra (SN). This decrease appears 1 day after injection, remains stable for at least 30 days, and is accompanied by a dose‐dependent long‐lasting decrease in TH‐ and DA transporter‐immunoreactivity in the striatum, which peaked 1 day after treatment and persisted for at least 30 days, however, some recovery was evident from day 3 onwards, evidencing sprouting of TH fibers. No change is observed in the NAc indicating that MDMA causes selective destruction of DA‐containing neurons in the nigrostriatal pathway, sparing the mesolimbic pathway. The expression of Mac‐1 increased 1 day after MDMA treatment and glial fibrillary acidic protein increased 3 days post‐treatment in the striatum and SN but not in the NAc, in strict anatomical correlation with dopaminergic damage. These data provide the first evidence that MDMA causes persistent loss of dopaminergic cell bodies in the SN.