Amphetamine toxicities

Methamphetamine and MDMA cause long-lasting reductions in markers of biogenic amine neurotransmission, traditionally linked to nerve terminal damage, in rodents, nonhuman primates, and humans. Recent evidence shows damage may extend to cell bodies of various neurons and blood–brain barrier endothelial cells. The damage involves oxidative stress, excitotoxicity, neuroinflammation, ubiquitin proteasome dysfunction, and mitochondrial and neurotrophic factor impairment. These mechanisms overlap with those in chronic stress and HIV infection, both of which amplify methamphetamine toxicity. The frequent co-occurrence of substituted amphetamine abuse with HIV or chronic stress suggests increased vulnerability to neurotoxicity in these individuals.

Study at a glance

Abstract

The drugs of abuse, methamphetamine and MDMA, produce long‐term decreases in markers of biogenic amine neurotransmission. These decreases have been traditionally linked to nerve terminals and are evident in a variety of species, including rodents, nonhuman primates, and humans. Recent studies indicate that the damage produced by these drugs may be more widespread than originally believed. Changes indicative of damage to cell bodies of biogenic and nonbiogenic amine–containing neurons in several brain areas and endothelial cells that make up the blood–brain barrier have been reported. The processes that mediate this damage involve not only oxidative stress but also include excitotoxic mechanisms, neuroinflammation, the ubiquitin proteasome system, as well as mitochondrial and neurotrophic factor dysfunction. These mechanisms also underlie the toxicity associated with chronic stress and human immunodeficiency virus (HIV) infection, both of which have been shown to augment the toxicity to methamphetamine. Overall, multiple mechanisms are involved and interact to promote neurotoxicity to methamphetamine and MDMA. Moreover, the high coincidence of substituted amphetamine abuse by humans with HIV and/or chronic stress exposure suggests a potential enhanced vulnerability of these individuals to the neurotoxic actions of the amphetamines.