Single-dose methamphetamine administration impairs ORM retrieval in mice via excessive DA-mediated inhibition of PrL^Glu activity

Methamphetamine (METH), an abused psychostimulant, impairs cognition through prolonged or even single-dose exposure, but animal experiments have shown contradictory effects on memory deficits. In this study we investigated the effects and underlying mechanisms of single-dose METH administration on the retrieval of object recognition memory (ORM) in mice. We showed that single-dose METH administration (2 mg/kg, i.p.) significantly impaired ORM retrieval in mice. Fiber photometry recording in METH-treated mice revealed that the activity of prelimbic cortex glutamatergic neurons (PrL^Glu) was significantly reduced during ORM retrieval. Chemogenetic activation of PrL^Glu or glutamatergic projections from ventral CA1 to PrL (vCA1^Glu-PrL) rescued ORM retrieval impairment. Fiber photometry recording revealed that dopamine (DA) levels in PrL of METH-treated mice were significantly increased, and micro-infusion of the D2 receptor (D2R) antagonist sulpiride (0.25 μg/side) into PrL rescued ORM retrieval impairment. Whole-cell recordings in brain slices containing the PrL revealed that PrL^Glu intrinsic excitability and basal glutamatergic synaptic transmission were significantly reduced in METH-treated mice, and the decrease in intrinsic excitability was reversed by micro-infusion of Sulpiride into PrL in METH-treated mice. Thus, the impaired ORM retrieval caused by single-dose METH administration may be attributed to reduced PrL^Glu activity, possibly due to excessive DA activity on D2R. Selective activation of PrL^Glu or vCA1^Glu-PrL may serve as a potential therapeutic strategy for METH-induced cognitive dysfunction.