Methamphetamine (METH) is a common abused drug. METH‐triggered glutamate (Glu) levels in dorsal CA1 (dCA1) could partially explain the etiology of METH‐caused abnormal memory, but the synaptic mechanism remains unclear. Here, we found that METH withdrawal disrupted spatial memory in mice, accompanied by the increases in Glu levels and postsynaptic neuronal activities at dCA1 synapses. METH withdrawal weakened the capacity of Glu clearance in astrocytes, as indicated by increasing the A1‐like astrocytes and phosphorylated signal transducer and activator of transcription 3 (p‐STAT3), decreasing the Glu transporter 1(GLT‐1, also known as EAAT2 or SLC1A2), Glu‐aspartate‐transporter (GLAST also known as EAAT1 or SLC1A3) and astrocytic glutamine synthase (GS), but failed to affect the presynaptic Glu release from dCA3 within dCA1. Moreover, we identified that in vitro A1‐like astrocytes exhibited an increased STAT3 activation and the impaired capacity of Glu clearance. Most importantly, selective knockdown of astrocytic STAT3 in vivo in dCA1 restored the astrocytic capacity of Glu clearance, normalized Glu levels at dCA1 synapses, and finally rescued METH withdrawal‐disrupted spatial memory in mice. Thus, astrocytic Glu clearance system, especially STAT3, serves as a novel target for future therapies against METH neurotoxicity.

Paternal methamphetamine (METH) exposure results in long-term behavioural deficits in the sub-generations with a sex difference. Here, we aim to investigate the sex-specific neurobehavioural outcomes in the first-generation offspring mice (F1 mice) paternally exposed to METH prior to conception and explore the underlying brain mechanisms. We found that paternal METH exposure increased anxiety-like behaviours and spatial memory deficits only in female F1 mice and caused depression-like behaviours in the offspring without sex-specific differences. In parallel, METH-sired F1 mice exhibited sex-specific brain activity pattern in response to mild stimulus (in water at room temperature for 3 min). Overall, paternal METH exposure caused a blunting phenomenon of prelimbic cortex (PrL), infralimbic cortex (IL) and nucleus accumbens (NAc) core in both male and female F1 mice, as indicated by the decreased c-Fos levels under mild stimulus. Of note, the activity of central nucleus of the amygdala (CeA) by mild stimulus was triggered in male but suppressed in female F1 mice, whereas the neurons of orbitofrontal cortex (OFC), cingulate cortex (Cg1), NAc shell, medial habenula (mHb), dorsal hippocampal CA1 (dCA1) and ventral hippocampal CA1 (vCA1) were only blunted in female F1 mice. Taken together, the distinct brain stimulation patterns between male and female F1 mice might contribute to the sex-specific behavioural outcomes by paternal METH exposure, which indicate that sex differences should be considered in the treatment of offspring paternally exposed drugs.

24Methamphetamine (METH) is frequently abused drug and produces cognitive deficits. METH could 25 induce hyper-glutamatergic state in the brain, which could partially explain METH-related cognitive 26 deficits, but the synaptic etiology remains unclear. Here, we investigated the role of dCA1 tripartite 27 synapses and the potential therapeutic effects of electro-acupuncture (EA) in the METH withdrawal-28 induced spatial memory deficits. METH withdrawal weakened astrocytic capacity of Glu uptake, but 29 failed to change Glu release from dCA3, resulting in hyper-glutamatergic excitotoxicity at dCA1 30 tripartite synapses. By restoring the astrocytic capacity of Glu uptake, EA treatments suppressed the 31 hyper-glutamatergic state and normalized the excitability of postsynaptic neuron in dCA1, finally 32 alleviated spatial memory deficits in METH withdrawal mice. These findings indicate that astrocyte 33 at tripartite synapses might be a novel target for developing therapeutic interventions against METH-34 associated cognitive disorders, and EA represent a promising non-invasive therapeutic strategy for 35 the management of drugs-caused neurotoxicity.36 3

As a highly addictive psychostimulant drug, paternal methamphetamine (METH) exposure enhances the risk of developing addiction to drugs in descendants, however the underlying mechanism remains unclear. Medial prefrontal cortex (mPFC) is a key brain region that implicated in susceptibility to drugs. Here, male adult mice were exposed to METH for 30 days, followed by mating with naive female mice to create the first-generation (F1) mice. In METH-sired mice, baseline levels of c-Fos were decreased but β1-adrenergic receptor (ADRB1) were increased in mPFC by paternal METH exposure. Trained with subthreshold-dosed administration of METH, METH-sired mice exhibited significant METH-preferred behaviors, accompanied with higher levels of c-Fos, ADRB1 and dendritic spines density in mPFC. Importantly, local blocking ADRB1 activity or specific knockdown of ADRB1 on excitatory neurons of mPFC, both efficiently inhibited METH-preferred behaviors in METH-sired mice. In parallel, levels of p-ERK1/2 and ΔFosB, as well as dendritic spine density were reduced by knocking-down mPFC ADRB1 in METH-sired mice. Collectively, these findings suggested that targeting ADRB1 signals in mPFC may represent a promising therapeutic strategy for preventing drug addiction, particularly in progeny with a history of paternal drugs exposure.