Methamphetamine effects in zebrafish (Danio rerio) depend on behavioral endpoint, dose and test session duration

Area of Science:

• Neuroscience
• Behavioral Pharmacology
• Zebrafish Models

Background:

• Zebrafish (Danio rerio) are increasingly used in behavioral pharmacology research.
• Limited data exist on methamphetamine's effects in adult zebrafish, with poorly defined exposure parameters.
• Short test sessions may mask drug effects due to anxiety-like behaviors from novel environments.

Purpose of the Study:

• To investigate the effects of methamphetamine on zebrafish behavior using extended test sessions.
• To determine optimal exposure parameters for observing methamphetamine's behavioral pharmacology in zebrafish.

Main Methods:

• Adult zebrafish were exposed to a range of methamphetamine doses (0.1–3.0 mg/L) via immersion.
• Locomotor activity was recorded for 50 minutes, a duration longer than typical studies.
• Behavioral parameters included swimming velocity, distance traveled, freezing time, and tank zone preferences.

Main Results:

• Methamphetamine did not significantly alter swimming velocity, distance, or freezing time.
• A dose-dependent decrease in bottom-zone occupancy and increased top-zone visits were observed.
• Methamphetamine increased side-transition counts, with effects appearing 10-20 minutes post-exposure.

Conclusions:

• Extended test sessions (50 min) are necessary to reveal methamphetamine's behavioral effects in zebrafish.
• Anxiety-like behaviors from procedural stress can interfere with observing drug effects in shorter sessions.
• Habituation to testing procedures is recommended for accurate methamphetamine behavioral assessment in zebrafish.