7-OH-DPAT has d-amphetamine-like discriminative stimulus properties

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Stimulant drugs like d-amphetamine are widely abused.
• Understanding the neurobiological mechanisms underlying stimulant drug discrimination is crucial for developing effective treatments.
• Dopamine pathways are implicated in the rewarding and reinforcing effects of stimulants.

Purpose of the Study:

• To investigate the role of dopamine D2/D3 receptors in the discriminative stimulus properties of d-amphetamine.
• To determine if a dopamine D2/D3 receptor agonist, 7-OH-DPAT, can substitute for d-amphetamine in a drug discrimination task.
• To examine the effects of a dopamine D2/D3 receptor antagonist, eticlopride, on 7-OH-DPAT substitution.

Main Methods:

• Rats were trained to discriminate between d-amphetamine (1 mg/kg) and saline using food-maintained responding (FR25 schedule).
• In extinction tests, rats were administered various doses of d-amphetamine or 7-OH-DPAT, and responding was recorded.
• The effects of eticlopride pretreatment on 7-OH-DPAT substitution were assessed.

Main Results:

• Decreasing doses of d-amphetamine resulted in a decrease in drug-appropriate responding.
• The dopamine D2/D3 receptor agonist 7-OH-DPAT fully substituted for the d-amphetamine discriminative stimulus at doses of 0.1, 0.3, and 1.0 mg/kg.
• This substitution was associated with a significant reduction in overall response rates.
• Eticlopride partially blocked the substitution produced by 7-OH-DPAT.

Conclusions:

• The dopamine D2/D3 receptor agonist 7-OH-DPAT shares discriminative stimulus properties with d-amphetamine.
• Dopamine D2/D3 receptors play a significant role in mediating the discriminative effects of d-amphetamine.
• These findings contribute to understanding the neurochemical basis of stimulant drug discrimination and potential therapeutic targets.