Hallucinogens

Question 1

Define psychedelics

Answer 1

drugs which liberate the mind

Question 2

Define entheogens

Answer 2

drugs which bring out the inner god

Question 3

What are the classes of hallucinogen?

Answer 3

indolealkylamines

phenylethylamines

Question 4

What are indolealkylamines and their structure?

Answer 4

similar structure to 5HT
naturally occurring; as an insecticide
e.g. LSD, psilocybin

Question 5

What is LSD?

Answer 5

lysergic acid diethylamide
active ingredient from ergot fungus
taken via blotter paper or liquid
effects; seeing shapes, intense visual experience, euphoria, synaesthesia, time suspension

Question 6

What risks are associated with LSD?

Answer 6

hallucinogen persisting perception disorder
flashbacks
psychosis (delusions)
paranoia
not long-lasting mental health problems

Question 7

What is psilocybin?

Answer 7

the active ingredient found in the psilocybe mushroom
used by aztecs and mayans (indoalkylamine)
positive persistent effects; meaningful, positive life changing experiences

Question 8

What is sclerotium tampenensis?

Answer 8

the active ingredient of the tampanensis mushroom (indoalkylamine)

Question 9

What are phenylethylamines and their structure?

Answer 9

structural similarity to dopamine and norepinephrine

mixed hallucinogenic and stimulant effects

Question 10

What is mescaline?

Answer 10

the active ingredient in the peyote cactus
ingested fresh/powder form
similar effects to LSD
legal for use in native indian american religious ceremonies
naturally occurring phenylethylamine

Question 11

What is methoxyamphetamine?

Answer 11

MDMA
synthetic drug that resembles amphetamine
synthetic phenylethylamine

Question 12

What are the effects of MDMA?

Answer 12

wakefulness, endurance, energy, euphoria, wellbeing, empathy, sharpened sensory perception, flight of ideas, anxiety, difficulty concentrating

Question 13

How is serotonin synthesised?

Answer 13

from l-tryptophan in the diet
L-trypt + tryptophan hyroxylase = l-5-hyroxytryptophan
l-5-hyroxy + l-amino acid decarboxylase = 5-HT

Question 14

What is the serotonin pathway?

Answer 14

cell bodies in the brainstem (dorsal raphe nucleus) project everywhere in the cortex

Question 15

What are the types of serotonergic receptor?

Answer 15

5HT-1 - 15
all metabotropic (except 5-HT3A)
auto receptors; 5-HT1A, B, D
5-HT1A; inhibits cAMP production and activates K+ channel opening
5-HT2A; excites protein kinase C and increases intracellular Ca2+

Question 16

What are the mechanisms of action of LSD?

Answer 16

5HT1A receptor agonist in raphe nuclei
- inhibits firing of raphe neurons
- does not account for hallucinogenic effects
5HT2A receptor agonist
- hallucinogenic effects are absent in knockouts (head twitch)
- correlation between binding and hallucinogenic effects
- 5HT2A antagonists (riperidone) block subjective effects

Question 17

What is the primary mechanism of the hallucinogenic effects of LSD?

Answer 17

preferential activation of later V pyramidal neurons in PFC via increased 5HT2AR stimulation

Question 18

What is the primary mechanism of action of MDMA?

Answer 18

indirect serotonergic agonist; enters synaptic terminal via SERT and promotes release from vesicle by reversing function of SERT
increases 5HT release into synapse
increases release of DA and NE
evidence; SSRIs inhibit actions of MDMA by blocking the action of SERT (citalopram)

Question 19

What is the function of 5HT1A?

Answer 19

inhibits cAMP production and activates K+ channel opening

Question 20

What is the function of 5HT2A?§

Answer 20

excites protein kinase C and increases intracellular Ca2+