Serial exposure to ethanol drinking and methamphetamine enhances glutamate excitotoxicity

Area of Science:

• Neuroscience
• Neuropharmacology
• Toxicology

Background:

• Alcohol and methamphetamine abuse frequently co-occur.
• The neurochemical effects of combined alcohol and methamphetamine exposure are not well understood.
• Both substances independently affect glutamatergic transmission, but their serial effects on dopamine neuron damage are unknown.

Purpose of the Study:

• To investigate the neurochemical consequences of serial alcohol and methamphetamine exposure.
• To determine the role of glutamate signaling in mediating dopamine neuron damage from co-abuse.
• To examine the neuroprotective potential of ceftriaxone against these effects.

Main Methods:

• Sprague-Dawley rats were given intermittent access to ethanol (EtOH) followed by methamphetamine (Meth) or saline.
• Glutamate transporters and extracellular glutamate levels in the striatum were measured.
• Effects of ceftriaxone administration during EtOH drinking were assessed.

Main Results:

• Ethanol drinking decreased glutamate aspartate transporter (GLAST) and increased basal extracellular glutamate.
• Ceftriaxone prevented these EtOH-induced changes in GLAST and glutamate.
• Ethanol drinking potentiated Meth-induced increases in extracellular glutamate, spectrin proteolysis, and dopamine depletion, effects attenuated by ceftriaxone.

Conclusions:

• Ethanol-induced alterations in glutamate uptake contribute to vulnerability to methamphetamine neurotoxicity.
• Serial alcohol and methamphetamine exposure causes unique neurotoxicity not seen with individual drug use.
• Ceftriaxone shows potential in mitigating the neurotoxic effects of combined alcohol and methamphetamine abuse.