Developmental Exposure to Psychostimulant Primes Activity-dependent Gene Induction in Frontal Cortex

Area of Science:

• Neuroscience
• Molecular Biology
• Developmental Psychology

Background:

• Perinatal neurodevelopment is critical for establishing neural connections.
• Early psychostimulant exposure poses risks for later cognitive and affective disorders.
• Molecular mechanisms linking early psychostimulant exposure to long-term effects are unclear.

Purpose of the Study:

• Investigate amphetamine's impact on activity-dependent Arc gene induction in neonatal mouse frontal cortex.
• Determine if amphetamine exposure causes lasting molecular changes in neural circuits.
• Identify molecular targets of psychostimulants during perinatal development.

Main Methods:

• Neonatal mice exposed to amphetamine.
• Measured Arc mRNA expression following activity-dependent induction.
• Assessed histone modifications (H3K4me1) at the Arc locus.
• Examined CREB phosphorylation.
• Investigated dopamine receptor signaling involvement.

Main Results:

• Amphetamine amplified immediate Arc mRNA expression.
• Amphetamine potentiated subsequent Arc mRNA induction without re-exposure.
• This priming effect correlated with increased H3K4me1 at the Arc locus.
• H3K4me1 increase required dopamine receptor signaling.
• No long-lasting CREB phosphorylation changes were observed.

Conclusions:

• Developmental amphetamine exposure induces lasting chromatin changes (H3K4me1) at the Arc locus.
• This epigenetic modification primes activity-dependent Arc gene induction.
• These findings reveal molecular mechanisms for psychostimulant-induced long-term psychiatric risks.