Heterozygote Dopamine Transporter Knockout Rats Display Enhanced Cocaine Locomotion in Adolescent Females

Area of Science:

• Neuroscience
• Pharmacology
• Genetics

Background:

• Cocaine is a widely abused psychostimulant, with the dopamine transporter (DAT) mediating its rewarding effects.
• Altered DAT expression is linked to increased drug abuse rates and psychiatric comorbidities.
• Understanding sex differences in response to cocaine is crucial for addiction research.

Purpose of the Study:

• To investigate the effects of cocaine on locomotor behaviors in adolescent rats with varying DAT expression levels.
• To examine potential sex-based differences in adolescent responses to cocaine.
• To explore the role of alpha synuclein (α-syn) and PICK 1 proteins in cocaine susceptibility.

Main Methods:

• Utilized a novel DAT transgenic rat model.
• Administered acute and chronic doses of cocaine to adolescent rats.
• Assessed locomotor behaviors and measured DAT, α-syn, and PICK 1 protein expression.

Main Results:

• Female rats exhibited higher sensitivity to cocaine at lower doses, indicating greater vulnerability.
• Male DAT heterozygous (HET) adolescents showed more pronounced and sustained locomotor responses to high-dose acute cocaine.
• Chronic cocaine exposure augmented effects in HET DAT adolescent female rats.
• DAT knockout (KO) rats displayed significant basal hyperactivity, suggesting a possible ceiling effect.
• Lower expression of α-syn and PICK 1 proteins was observed in female HET and KO rats.

Conclusions:

• Adolescent DAT mutations significantly influence behavioral responses to cocaine, with notable sex differences.
• Female rats with reduced DAT expression show increased vulnerability to cocaine, potentially linked to lower α-syn and PICK 1 levels.
• This research highlights the importance of considering genetic factors and sex in adolescent cocaine abuse susceptibility.