Prolonged Amphetamine Treatments Cause Long-Term Decrease of Dopamine Uptake in Cultured Cells.

Area of Science:

• Neuroscience
• Pharmacology
• Cell Biology

Background:

• Amphetamine (AMPH) is a stimulant treating ADHD, narcolepsy, and obesity.
• AMPH inhibits dopamine (DA) and norepinephrine (NE) reuptake by binding to catecholamine transporters.
• Therapeutic and recreational use of AMPH involves prolonged exposure, necessitating investigation into long-term effects.

Purpose of the Study:

• To investigate the prolonged effects of amphetamine (AMPH) on dopamine (DA) uptake.
• To determine if AMPH-induced reductions in DA uptake persist through cell division.
• To assess AMPH's long-term effects in cell models relevant to neuronal function.

Main Methods:

• LLC-PK1 cells stably expressing human dopamine transporter (hDAT) were pretreated with AMPH (1 or 50 µM) for 15 hours.
• SH-SY5Y neuroblastoma cells were pretreated with AMPH (50 µM) and differentiated with retinoic acid (RA).
• DA uptake, cell viability, ATP, and ROS levels were measured after pretreatment and subsequent cell divisions.

Main Results:

• AMPH (1 and 50 µM) pretreatment significantly reduced DA uptake in LLC-PK1 cells immediately after 15 hours.
• AMPH (50 µM) pretreatment led to reduced DA uptake persisting after 1, 2, and 3 cell divisions in LLC-PK1 cells.
• AMPH (50 µM) significantly reduced DA uptake in SH-SY5Y cells after 15 hours and 3 cell divisions, without affecting cell viability, ATP, or ROS.

Conclusions:

• Amphetamine (AMPH) induces long-term effects on dopamine (DA) uptake that are maintained across cell divisions.
• These sustained effects were observed in both kidney (LLC-PK1) and neuronal (SH-SY5Y) cell models.
• AMPH's long-term impact on DA uptake occurs independently of cellular toxicity.