Hallucinogens Flashcards
What is a hallucinogen?
Psychoactive agent that causes changes in perception by altering the function of monoaminergic or glutamatergic systems.
What is the 5 criteria required to classify a drug as a hallucinogen?
- Predominant changes in mood, perception, and thought.
- Minimal intellectual and memory impair.
- Excessive stimulation/stupor and narcosis should not be excessive.
- ANS side effects should be minimal.
- Addictive craving should be absent.
What are classical psychedelics?
Drugs with perception-altering effects like hallucinations and disorganized thoughts. Include LSD, psilocybin, and mescaline.
What is the common receptor activated by classical psychedelics?
5HT2a receptor.
Why are not all 5HT2a receptors hallucinogenic?
Biased agonism.
What pathway does LSD activate?
Activates phospholipase A2, Gs coupled pathway.
What kind of agonist is LSD?
Partial.
Describe LSD tolerance
A single dose of LSD will lead to profound tolerance due to the downregulation of 5-HT2 receptors, but not other 5-HT receptors. Involves cross-tolerance.
What is psilocybin?
Indole molecule structurally similar to serotonin; causes euphoria and visual/mental hallucinations. Prodrug that rapidly dephosphorylates into psilocyin.
Partial agonist at 5HT, high affinity for 5HT-2b and 2c, lower affinity for 2a.
What are dissociative hallucinogenics?
Distort perception of sight and sound, cause sense of detachment. Often associated with analgesia.
What is phencyclidine?
NMDA receptor antagonist that also acts as an inhibitor at the dopamine transporter to increase synaptic dopamine levels. Addiction liability.
What is nitrous oxide?
Laughing gas: dissociative anesthetic that leads to feelings of euphoria and depersonalization. Low potency, non-competitive NMDA antagonist that stimulates endogenous opioid release. Also a positive allosteric modulator at GABAa receptors.
What are deliriant hallucinogens?
Hallucinogens that induce a state characterized by extreme confusion and inability to control actions. Images and hallucinations produced seem real to the patient (low lucidity).
What receptors to deliriant hallucinogens tend to block?
Muscarinic acetylcholine receptors.
What is datura?
Deliriant hallucinogen, competitive antagonist at muscarinic cholinergic receptors.
