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A General Method for Evaluating Deep Brain Stimulation Effects on Intravenous Methamphetamine Self-Administration
Published on: January 22, 2016
[Microglia-mediated cognitive impairment induced by methamphetamine]
Naotaka Izuo1,2, Yuka Kusui1,3, Atsumi Nitta1
1Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, University of Toyama.
Abstract:
More than half of chronic methamphetamine (METH) users exhibit multi-domain cognitive deficits, including impaired attention, executive function, and memory. MRI studies consistently demonstrate hippocampal atrophy and frontotemporal cortical thinning; these structural changes spatially overlap with glial activation, indicating the coexistence of morphological damage and ongoing neuroinflammation. To clarify causality, we developed a mouse model in which low-dose METH is micro-infused into the nucleus accumbens. The mice displayed cognitive dysfunction and hippocampal long-term potentiation deficits together with microglial activation and mRNA up-regulation of IL-1β and the complement component C1q. Suppressing microglial activation with minocycline normalized these soluble factors and restored cognitive function. Complement proteins drive microglia-mediated synaptic pruning, and their over-activation has been implicated in Alzheimer's disease and schizophrenia. Taken together, our findings suggest that METH-induced cognitive impairment is mediated by abnormal microglial pruning via complement signaling. This review summarizes the clinical phenotype of METH-related cognitive dysfunction, integrates preclinical findings, and proposes novel therapeutic avenues that target microglial activation.
Insights
Methamphetamine (METH) use causes cognitive deficits by activating microglia, leading to synaptic pruning. Suppressing this microglial activation with minocycline restored cognitive function in a mouse model.
Area of Science:
- Neuroscience
- Neuroinflammation
- Neuropharmacology
Background:
- Chronic methamphetamine (METH) use is linked to cognitive deficits and brain structural changes.
- Neuroinflammation, indicated by glial activation, co-occurs with morphological damage in METH users.
- Microglial activation and complement signaling are implicated in neurodegenerative and psychiatric disorders.
Purpose of the Study:
- To investigate the causal link between METH, neuroinflammation, and cognitive dysfunction.
- To explore the role of microglial activation and complement signaling in METH-induced cognitive impairment.
- To identify potential therapeutic targets for METH-related cognitive deficits.
Main Methods:
- Developed a mouse model with nucleus accumbens micro-infusion of low-dose METH.
- Assessed cognitive function, hippocampal long-term potentiation, and microglial activation markers (IL-1β, C1q).
- Administered minocycline to suppress microglial activation and evaluated its effects.
Main Results:
- METH-infused mice exhibited cognitive deficits and impaired hippocampal long-term potentiation.
- These mice showed increased microglial activation and elevated IL-1β and C1q mRNA levels.
- Minocycline treatment normalized these molecular markers and restored cognitive function.
Conclusions:
- METH-induced cognitive impairment is mediated by abnormal microglial pruning via complement signaling.
- Targeting microglial activation presents a promising therapeutic strategy for METH-related cognitive dysfunction.
- This study provides a preclinical basis for developing novel treatments for stimulant use disorder.
