Related Experiment Video
Updated: Jul 11, 2026
A General Method for Evaluating Deep Brain Stimulation Effects on Intravenous Methamphetamine Self-Administration
Published on: January 22, 2016
A comparison of amphetamine- and methamphetamine-induced locomotor activity in rats: evidence for qualitative
Darien A Hall1, Jessica J Stanis, Hector Marquez Avila
1Department of Psychology and Neuroscience Program, University of Illinois at Urbana-Champaign, 731 Psychology Bldg MC-716, 603 E Daniel St, Champaign, IL 61820, USA.
Rationale:
Methamphetamine (METH) is typically characterized as a more potent psychostimulant than amphetamine (AMPH), but few studies have directly compared the effects of these drugs at low, behaviorally activating doses that tend not to produce focused stereotypy.
Objectives:
The objective of the study was to compare the effects of AMPH or METH treatment on locomotor activity in an open-field arena, focusing on their ability to produce conditioned locomotor activity, sensitization, and cross-sensitization.
Materials And Methods:
Adult male rats were given AMPH or METH (0.5 or 1.0 mg/kg) for 5 days, with half of the rats presented with discrete, salient stimuli (S+) during the postinjection period. After a 3-day withdrawal, they were given three different injections on successive days: a saline challenge to assess conditioned responding, a drug challenge to assess sensitization, and a cross-sensitization test to the same dose of the drug with which they were not pretreated.
Results:
Except in certain conditions, AMPH and METH were equipotent at activating locomotor activity. The exceptions included when rats were presented with S+ on acute and drug challenge days and in tests of cross-sensitization. There were no consistent differences in the magnitude of sensitization produced by AMPH or METH, and both drugs produced similar amounts of conditioned locomotion after a saline injection.
Conclusions:
We have found specific conditions where METH is more potent than AMPH, but this study and others that used higher doses of these drugs are not consistent with the generalized characterization of METH as a more potent psychostimulant.
Insights
Methamphetamine (METH) and amphetamine (AMPH) showed similar effects on locomotor activity in rats at low doses. Specific conditions revealed METH as more potent, challenging its general characterization as a stronger psychostimulant.
Area of Science:
- Neuroscience
- Psychopharmacology
- Behavioral Science
Background:
- Methamphetamine (METH) is often considered more potent than amphetamine (AMPH).
- Few studies directly compare low, behaviorally activating doses of METH and AMPH.
- Stereotypy is not consistently observed at these low doses.
Purpose of the Study:
- Compare locomotor activity effects of AMPH and METH in rats.
- Investigate conditioned locomotor activity, sensitization, and cross-sensitization.
- Evaluate drug potency at low, activating doses.
Main Methods:
- Adult male rats received AMPH or METH (0.5 or 1.0 mg/kg) for 5 days.
- Salient stimuli (S+) were presented to half the rats post-injection.
- Locomotor activity was assessed via challenges after a 3-day withdrawal period.
Main Results:
- AMPH and METH were generally equipotent in activating locomotor activity.
- METH showed greater potency in specific conditions, including S+ presentation and cross-sensitization tests.
- No significant differences in sensitization magnitude were found between METH and AMPH.
Conclusions:
- METH is not consistently more potent than AMPH at low, activating doses.
- Specific experimental conditions can reveal higher potency for METH.
- Findings challenge the generalized view of METH as a superior psychostimulant compared to AMPH.
Related Concept Videos
01:25Adrenergic Agonists: Indirect-Acting Agents
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
01:24CNS Stimulants: Cocaine, Amphetamines and Cannabinoids
01:23Drugs Acting on Autonomic Ganglia: Stimulants
Ganglionic stimulants activate NM nicotinic receptors in autonomic ganglia, falling into two categories: nicotine mimetics [e.g., lobeline, dimethylpiperazine, tetramethylammonium] and muscarinic receptor agonists [e.g., muscarine, methacholine]. The first category's action is rapid and blocked by nicotinic receptor antagonists, while the second category's action is delayed and blocked by atropine-like agents. Nicotine, an alkaloid, affects the heart rate by stimulating sympathetic or...