Related Experiment Video
Updated: Aug 18, 2026
Three Laboratory Procedures for Assessing Different Manifestations of Impulsivity in Rats
Published on: March 17, 2019
Acute yohimbine increases laboratory-measured impulsivity in normal subjects
Alan C Swann1, Daniel Birnbaum, Ashley A Jagar
1Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, Texas 77030, USA. Alan.C.Swann@uth.tmc.edu
Background:
State-dependent changes in impulsivity may be related to norepinephrine. To examine possible relationships between norepinephrine and acute changes in impulsivity, we measured effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on laboratory-measured impulsivity in healthy subjects without psychiatric or substance-use disorders.
Methods:
Impulsivity was assessed using the Immediate and Delayed Memory Tasks (IMT-DMT), derived from the Continuous Performance Test, before and after placebo or two doses of yohimbine, given 4 days apart. Blood pressure was monitored, and psychiatric symptoms were measured using self-rated visual analog scales.
Results:
Yohimbine was associated with a dose-related increase in impulsive IMT commission errors, with an increase of > 50% relative to baseline at the higher dose. The activation factor of the Internal State Scale was increased at the same dose.
Conclusions:
These results are consistent with increased impulsivity in normal subjects given yohimbine, possibly related to increased norepinephrine.
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...
01:30Attention-Deficit/Hyperactivity Disorder
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings.
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...
01:21Drugs Affecting Neurotransmitter Release or Uptake
01:16Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
01:15Drug Abuse and Addiction: Pharmacological Phenomena