Related Experiment Video

Updated: Feb 5, 2026

Creating Dynamic Images of Short-lived Dopamine Fluctuations with lp-ntPET: Dopamine Movies of Cigarette Smoking
14:21

Creating Dynamic Images of Short-lived Dopamine Fluctuations with lp-ntPET: Dopamine Movies of Cigarette Smoking

Published on: August 6, 2013

18.8K

Dopamine and serotonin antagonists fail to alter the discriminative stimulus properties of

Susan Schenk1, Quenten Highgate

  • 1School of Psychology, Victoria University of Wellington, Wellington, New Zealand.

Behavioural Pharmacology
|September 11, 2018
PubMed

Insights

Higher doses of MDMA (3,4-methylenedioxymethamphetamine) involve both dopamine and serotonin systems. Dopamine antagonists blocked amphetamine discrimination but not MDMA, suggesting flexible mechanisms for MDMA

Area of Science:

  • Neuroscience
  • Pharmacology
  • Behavioral Science

Background:

  • Discriminative stimulus effects of 3,4-methylenedioxymethamphetamine (MDMA) are typically studied at low doses (1.5 mg/kg), implicating serotonergic mechanisms.
  • Dopaminergic mechanisms are known to mediate the effects of amphetamine (AMPH).
  • Higher doses of MDMA (3.0 mg/kg) may involve both dopaminergic and serotonergic pathways.

Purpose of the Study:

  • To investigate the role of selective dopamine (DA) and serotonin (5HT) antagonists in the discriminative stimulus effects of amphetamine (AMPH) and MDMA.
  • To determine if dopaminergic or serotonergic systems are necessary for the discriminative stimulus properties of AMPH and a higher dose of MDMA.

Main Methods:

  • Rats were trained to discriminate between AMPH (0.5 mg/kg) or MDMA (3.0 mg/kg) and saline using a food-reinforced drug-discrimination procedure.
  • The effects of selective DA antagonists (SCH 23390, eticlopride) and 5HT antagonists (ritanserin, WAY-100635, GR129375) on drug discrimination were assessed.
  • Antagonists were administered at specific dose ranges to evaluate their impact on stimulus generalization.

Main Results:

  • Both DA antagonists dose-dependently reduced AMPH discrimination but did not affect MDMA discrimination.
  • None of the tested 5HT antagonists altered the discriminative stimulus effects of either AMPH or MDMA.
  • The discriminative stimulus of MDMA (3.0 mg/kg) appears to involve both DAergic and 5HTergic components.

Conclusions:

  • Dopaminergic mechanisms are critical for the discriminative effects of AMPH.
  • The discriminative stimulus of a high dose of MDMA can be maintained by either dopaminergic or serotonergic pathways, as neither is strictly required.
  • This suggests a degree of flexibility in the neurobiological substrates mediating the subjective effects of MDMA at higher doses.

More Related Videos

Behavioral Determination of Stimulus Pair Discrimination of Auditory Acoustic and Electrical Stimuli Using a Classical Conditioning and Heart-rate Approach10:50

Behavioral Determination of Stimulus Pair Discrimination of Auditory Acoustic and Electrical Stimuli Using a Classical Conditioning and Heart-rate Approach

Published on: June 6, 2012

14.9K
Combined Infusion and Stimulation with Fast-Scan Cyclic Voltammetry CIS-FSCV to Assess Ventral Tegmental Area Receptor Regulation of Phasic Dopamine06:40

Combined Infusion and Stimulation with Fast-Scan Cyclic Voltammetry CIS-FSCV to Assess Ventral Tegmental Area Receptor Regulation of Phasic Dopamine

Published on: April 23, 2020

3.7K

Related Concept Videos

Drugs Affecting GI Tract Motility: Dopamine Receptor Antagonists01:28

Drugs Affecting GI Tract Motility: Dopamine Receptor Antagonists

Prokinetic agents are specialized medications that stimulate gastrointestinal (GI) motility, promoting food movement through the GI tract. Dopamine, an inhibitory neurotransmitter, plays a significant role in this process, reducing GI motility and indirectly controlling the speed of digestion. Dopamine receptor antagonists, such as metoclopramide and domperidone, offer a unique advantage as prokinetic agents. By blocking the dopamine receptors, these drugs increase GI motility, improving food...
1.4K
Chemotherapy-Induced Nausea and Vomiting: Dopamine Receptor Antagonists01:29

Chemotherapy-Induced Nausea and Vomiting: Dopamine Receptor Antagonists

Dopamine receptor antagonists, also known as antipsychotic agents, are critical in managing chemotherapy-induced vomiting. These antiemetic agents block dopamine receptors in the chemoreceptor trigger zone (CTZ), inhibiting signal transmission to the vomiting center. Antipsychotic agents encompass phenothiazines (PTZ), butyrophenones, benzamides, and thienobenzodiazepines (Zyprexa), which are utilized for their antiemetic and sedative properties.
Phenothiazines, such as prochlorperazine...
890
Stereotypes, Prejudice, and Discrimination02:55

Stereotypes, Prejudice, and Discrimination

Humans are very diverse and although we share many similarities, we also have many differences. The social groups we belong to help form our identities (Tajfel, 1974). These differences may be difficult for some people to reconcile, which may lead to prejudice toward people who are different. Prejudice is a negative attitude and feeling toward an individual based solely on one’s membership in a particular social group (Allport, 1954; Brown, 2010). Prejudice is common against people who...
95.4K
Hypothesis: Accept or Fail to Reject?01:17

Hypothesis: Accept or Fail to Reject?

The outcome of any hypothesis testing leads to rejecting or not rejecting the null hypothesis. This decision is taken based on the analysis of the data, an appropriate test statistic, an appropriate confidence level, the critical values, and P-values. However, when the evidence suggests that the null hypothesis cannot be rejected, is it right to say, 'Accept' the null hypothesis?
There are two ways to indicate that the null hypothesis is not rejected. 'Accept' the null...
29.6K
Alterations in Respiration II01:30

Alterations in Respiration II

There are numerous types of normal and abnormal respiration. Based on ventilatory movements, breathing patterns are classified as regular, deep, or shallow. Examples include Biot's breathing, Cheyne-Stokes respiration, Kussmaul's breathing, hyperventilation, and hypoventilation. Each pattern is clinically significant and aids in evaluating patients.
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
1.8K
Altered States of Awareness01:06

Altered States of Awareness

Altered states of consciousness represent significant deviations from one's normal mental state. These deviations can range from subtle changes in awareness to profound transformations in perception, thought processes, and sensory experiences. Altered states of consciousness can be triggered by various factors, including drug use, meditation, hypnosis, illness, or even intense fatigue.
The ingestion of substances like stimulants or hallucinogens leads to chemical alterations in the brain...
1.1K