Increased context-dependent conditioning to amphetamine in mice lacking TAAR1

Area of Science:

• Neuroscience
• Pharmacology
• Addiction Research

Background:

• Amphetamine derivatives are known psychostimulants with addictive potential.
• Recent evidence suggests amphetamines may directly activate the trace amine-associated receptor 1 (TAAR1).
• The role of TAAR1 in the behavioral effects and addiction liability of amphetamines remains largely unexplored.

Purpose of the Study:

• To investigate the contribution of TAAR1 to the reinforcing and addictive properties of amphetamines.
• To examine the effects of TAAR1 deficiency on context-dependent sensitization and conditioned place preference (CPP) to d-amphetamine (AMPH).
• To explore the neurobiological mechanisms underlying TAAR1's role in amphetamine conditioning.

Main Methods:

• Utilized TAAR1 knockout (TAAR1-KO) mice and wild-type littermates.
• Assessed context-dependent locomotor sensitization to AMPH.
• Evaluated AMPH-induced CPP and its reinstatement in TAAR1-KO and wild-type mice.
• Analyzed striatal levels and phosphorylation of the NMDA receptor subunit GluN1.

Main Results:

• TAAR1-KO mice exhibited significantly higher conditioned locomotor responses to AMPH compared to wild-type controls.
• TAAR1-KO animals showed increased sensitivity to priming-induced reinstatement of AMPH-associated CPP.
• Absence of TAAR1 led to alterations in total and phosphorylated GluN1 levels in the striatum of both saline- and AMPH-treated mice.
• These findings suggest a role for TAAR1 in modulating frontostriatal glutamate transmission.

Conclusions:

• TAAR1 receptors play an inhibitory role in mediating conditioned responses to amphetamines.
• TAAR1 influences amphetamine conditioning, at least partly, through the modulation of corticostriatal glutamate transmission.
• Targeting TAAR1 may offer a novel therapeutic strategy for mitigating amphetamine addiction.