Effect of subchronic treatment with methamphetamine on apomorphine-induced changes in locomotor activity in mice

Area of Science:

• Neuroscience
• Pharmacology
• Neurobiology

Background:

• Methamphetamine is a stimulant with known effects on the dopamine system.
• Apomorphine is a dopamine receptor agonist used to study dopaminergic function.
• Understanding drug interactions is crucial for managing substance use and neurological disorders.

Purpose of the Study:

• To investigate the effects of subchronic methamphetamine on dopamine receptor sensitivity.
• To determine if methamphetamine alters the response to apomorphine in mice.
• To examine the impact on presynaptic dopamine metabolism.

Main Methods:

• Mice received methamphetamine (3 mg/kg, s.c., twice daily for 14 days).
• Apomorphine (0.1 or 3 mg/kg, s.c.) was administered to assess motor activity.
• Striatal DOPA accumulation was measured after inhibiting L-amino acid decarboxylase.

Main Results:

• Methamphetamine attenuated low-dose apomorphine-induced hypomotility.
• Methamphetamine enhanced high-dose apomorphine-induced hypermotility.
• No significant changes in apomorphine-induced decrease in striatal DOPA accumulation were observed.

Conclusions:

• Subchronic methamphetamine treatment modulates behavioral responses to apomorphine.
• Presynaptic dopamine receptor sensitivity in the striatum appears unaffected by this treatment regimen.
• These findings suggest complex alterations in dopamine receptor signaling pathways.