20 Hallucinogens Flashcards
What is a hallucinogen?
a psychoactive agent that causes changes in thoughts, emotions, and consciousness
- most hallucinogen drugs alter function of the monoaminergic or glutamatergic systems
most hallucinogen drugs alter function of the _______\_or ________\_ systems
most hallucinogen drugs alter function of the monoaminergic (specifically serotonin) or glutamatergic systems
What are five criteria for a drug to be classified as a hallucinogen?
- In proportion to other effects, changes in thought, perception, and mood should predominate
- Intellectual or memory impairment should be minimal
- Stupor, narcosis, or excessive stimulation should not be an integral effect
- autonomic nervous system side effects should be minimal
- addictive craving should be absent = low abuse liability
What are classical psychedelics?
Include drugs with perception-altering psychedelic effects
- eg lysergic acid diethylamide (LSD)
- Psilocybin
- Mescaline
- Common mechanism of action at the serotonin 5HT2a receptor
What is the mechanism of action of classical psychedelics?
Common mechanism of action at the serotonin 5HT2a receptor
- these include drugs with perception-altering psychedelic effects
What drug did Albert Hofmann accidentally discover?
Lysergamides (LSD)
From what was LSD discovered from?
Ergot alkaloids which are produced by a fungus that grows on rye
- known to be good vasoconstrictors - potential treatment for migraine
- Pure ergot derivative not very stable in solution so Hofmann chemically manipulated it to make it more stable
- Ended up making lysergic acid diethylamide (LSD) = highly hallucinogenic
Why do ergot alkaloids have potential for treating migraines?
Good vasocontrictors
LSD has over _______ known targets including several _____ receptors
Remember: Low Ki = _____ affinity
LSD has over 50 known targets including several serotonin (5-HT) receptors
Remember: Low Ki = high affinity
LSD has the highest affinity for the _______ receptors
Serotonin
The hallucinogenic effects of LSD is mediated by ______ receptor
The hallucinogenic effects of LSD is mediated by 5HT-2a receptor
- LSD is a high affinity partial agonist at 5-HT2a receptors
How do we know 5HT-2a activation is responsible for hallucinations?
Transgenic mouse model lacking these receptors (5HT-2a knockout mice) do not show hallucinogenic like behavior to LSD
Are all 5HT-2a agonists hallucinogenic?
No
Why aren’t all 5HT-2a agonists hallucinogenic?
biased mechanism
- LSD activates phospholipase A2 instead of phospholipase C (like serotonin)
- Leads to different intracellular signalling pathways and regulation of different genes
What drug blocks the hallucinogenic effects of LSD in humans? How?
Ketanserin
- antagonist of 5HT2a
**In image should say LSD + ketanserin*** (NOT KETAMINE)