Methamphetamine-induced short-term increase and long-term decrease in spatial working memory affects protein Kinase M...

Area of Science:

• Neuroscience
• Addiction Research
• Cognitive Psychology

Background:

• Methamphetamine (MA) is a neurotoxic and addictive stimulant.
• MA's effects on learning and memory are complex and not fully understood.
• Adolescent brain development may be particularly vulnerable to MA's impact.

Purpose of the Study:

• To investigate the long-term effects of adolescent MA exposure on working memory and cognitive flexibility.
• To explore the underlying neural mechanisms in the hippocampus and striatum.
• To assess changes in glutamate and dopamine receptor expression and memory-related proteins.

Main Methods:

• Adolescent mice received weekly MA injections (30 mg/kg) for 5 weeks.
• Working and reference memory were assessed using the radial 8-arm maze (RAM).
• Post-abstinence, cognitive flexibility was re-evaluated, and brain tissue (hippocampus, striatum) was analyzed for specific protein and receptor expression.

Main Results:

• MA-treated mice initially showed improved working memory, but later exhibited significant working memory errors after abstinence.
• Hippocampal analysis revealed reduced PKMζ and GluA2, with increased GluN2B and decreased D1.
• Striatal analysis showed increased DAT and TH, reduced GluN2B, and increased PKMζ and PKCζ.

Conclusions:

• Adolescent MA exposure induces lasting working memory deficits and cognitive inflexibility.
• MA alters synaptic function in the hippocampus and dopamine signaling in the striatum.
• The study highlights the potential role of PKMζ/PKCζ in mediating MA-induced neuroadaptations and memory impairments.