Lecture 21 - Hallucinogens

Question 1

a psychoactive agent that causes changes in perception

Answer 1

hallucinogen

Question 2

most hallucinogen drugs alter function of the:

Answer 2

monoaminergic or glutamatergic neurotransmitter systems

Question 3

what are the four classes of hallucinogens?

Answer 3

1) classical psychedelics
2) dissociative agents
3) deliriants
4) oneirogens

Question 4

what distinguishes the classes of hallucinogens?

Answer 4

mechanism of action and effects

Question 5

includes drugs with perception-altering psychedelic effects, and have a common mechanism of action at the 5HT2a receptor

Answer 5

classical psychedelics

Question 6

lysergic acid diethylamide (LSD), psilocybin, and dimethyltryptamine (DMT) are all examples of:

Answer 6

classical psychedelics

Question 7

LSD was discovered accidentally by:

Answer 7

Dr. Albert Hofmann

Question 8

compounds that are produced by a fungus that grows on rye

Answer 8

ergot alkaloids

Question 9

ergot alkaloids are known to be good:

Answer 9

vasoconstrictors (why they were originally studied to treat cardiovascular disease and migraines)

Question 10

when Dr. Hofmann tried to chemically manipulate ergot alkaloids, he ended up making:

Answer 10

lysergic acid diethylamide (LSD)

Question 11

how many targets does LSD have?

Answer 11

50 known targets (including several serotonin receptors)

Question 12

LSD has a very high affinity for:

Answer 12

the 5HT2a receptor

Question 13

the hallucinogenic effects of LSD are mediated by:

Answer 13

5HT2a receptors

Question 14

LSD is a:

Answer 14

high affinity partial agonist at the 5HT2a receptor (and other 5HT receptors)

Question 15

how do we know 5HT2a activation is responsible for hallucinations?

Answer 15

transgenic mouse models lacking these receptors (knockout) do not show hallucinogenic like behaviour (head bobs) to LSD

Question 16

true or false: all 5HT2a agonists are hallucinogenic

Answer 16

false

Question 17

why is it that not all 5HT2a agonists are hallucinogenic?

Answer 17

biased agonism

Question 18

at the 5HT2a receptor, LSD activates:

Answer 18

the phospholipase C signalling pathway

Question 19

non-hallucinogenic 5HT2a agonists activate:

Answer 19

the beta-arrestin signalling pathway

Question 20

it was found that pretreatment with the 5HT2a receptor antagonist _______ blocked the effects of LSD

Answer 20

ketanserin

Question 21

what are the effects of LSD due to activity at the 5HT1 receptor?

Answer 21

dilated pupils, increases heart rate, and increases blood pressure

Question 22

what are the effects of LSD due to activity at the 5HT2b receptor?

Answer 22

valvopathies are possible with chronic use (even in microdoses)

Question 23

what type of hallucinations are caused by LSD?

Answer 23

distortion of sensory perception, range from simple colour patterns to more complex scenes, sometimes come with feelings of enlightenment

Question 24

what are the potential adverse psychiatric effects of using LSD?

Answer 24

anxiety, paranoia, and delusions

Question 25

distressing visual hallucinations that appear following drug use

Answer 25

hallucinogenic persisting perception disorder (HPPD)

Question 26

how is LSD tolerated in the body?

Answer 26

a single dose of LSD can lead to profound tolerance that lasts for several days

Question 27

tolerance of LSD is accompanied by:

Answer 27

downregulation of 5HT (but no other receptors)

Question 28

is cross tolerance of LSD with other hallucinogens acting at serotonin receptors possible?

Answer 28

yes

Question 29

classical psychedelic which contains an indole ring with an amine group (structurally similar to serotonin)

Answer 29

psilocybin

Question 30

what are the effects of using psilocybin?

Answer 30

euphoria, visual and mental hallucinations, changes in perception and a distorted sense of time, spiritual experiences

Question 31

what are the adverse effects of using psilocybin?

Answer 31

nausea and panic attacks

Question 32

true or false: psilocybin is a prodrug

Answer 32

true

Question 33

psilocybin is rapidly dephosphorylated into ______ when ingested orally

Answer 33

psilocin

Question 34

psilocin is a:

Answer 34

partial agonist at 5HT receptors

Question 35

psilocin has a high affinity for the _____ and _____ receptors, and slightly lower affinity for the _____ receptor

Answer 35

5HT2b, 5HT2c, and 5HT2a

Question 36

what causes the hallucinogenic effects of psilocin?

Answer 36

activity at the 5HT2a receptor

Question 37

type of hallucinogens which distort perceptions of sight and sound, and produce feelings of detachment from the environment or self

Answer 37

dissociative hallucinogens

Question 38

the use of dissociative hallucinogens is often associated with _____, and can lead to _____

Answer 38

analgesia, depersonalization (out of body experiences)

Question 39

phencyclidine (aka angel dust) is an:

Answer 39

NMDA recpetor antagonist, and an inhibitor at the dopamine transporter (DAT)

Question 40

the use of phencylidine (PCP) leads to:

Answer 40

increased synaptic levels of dopamine (increases release and blocks reuptake)

Question 41

why has phencyclidine (PCP) been largely replaced by ketamine as an anesthetic?

Answer 41

for its highly addictive effects

Question 42

dissociative hallucinogen which produces changes in body image, loss of ego boundaries, paranoia, and depersonalization

Answer 42

phyencyclidine (PCP)

Question 43

type of hallucinogen that induces a state of delirium characterized by extreme confusion and an inability to control ones actions

Answer 43

deliriant hallucinations

Question 44

both _____ and _____ can produce visual and auditory hallucinations

Answer 44

deliriant hallucinogens, psychedelics

Question 45

type of hallucination where imagery is often perceived as real and users may not be aware they are in a state of drug-altered consciousness (low lucidity)

Answer 45

deliriant hallucinations

Question 46

deliriant hallucinogens tend to block:

Answer 46

muscarinic acetylcholine receptors (anticholinergic)

Question 47

a widespread poisonous plant that contains tropane alkaloids such as scopolamine and atropine

Answer 47

datura stramonium

Question 48

atropine and scopolamine are:

Answer 48

competitive antagonists at the muscarinic cholinergic receptors

Question 49

symptoms of datura stramonium use include:

Answer 49

delirium, confusion, hallucinations, and loss of consciousness

Question 50

hallucinogen associated with systemic effects like dry mouth, dilated pupils, muscle stiffness, tachycardia, etc.

Answer 50

datura stramonium

Question 51

is the use of datura stramonium lethal?

Answer 51

yes (at high doses)

Question 52

true or false: at very high doses, first generation antihistamines can produce deliriant hallucinations (related to their anticholinergic effects)

Answer 52

true

Question 53

why are fist generation antihistamines a potentially inappropriate medication for older adults?

Answer 53

older adults are more susceptible to the delirium effects of first generation antihistamines

Question 54

a substance that produces a dreamlike state of consciousness

Answer 54

oneirogen

Question 55

salvinorin A is an:

Answer 55

agonist at the kappa opioid receptor

Question 56

salvinorin A is derived from:

Answer 56

the plant salvia divinorum

Question 57

produces very short acting hallucinations (~5 minutes); includes featues of classical psychedelics, dissociative hallucinogens, and anticholinergic deliriants; and is characterized by an immersive dream state similar to REM sleep

Answer 57

salvinorin A