Hallucinogens

Question 1

Hallucinogen

Answer 1

psychoactive agent that causes changes in perception
most alter the function of monoaminergic (serotonin) or glutamatergic systems

Question 2

Classes

Answer 2

differ in mechanism of action and effects

Question 3

Classical Psychedelics

Answer 3

targets 5-HT2a receptors
perception-altering psychedelic effects
sensory distortions

Question 4

LSD

Answer 4

good vasoconstrictor
low Ki = high affinity partial agonist at 5-HT2a
Gq cascade = activation of PLC
dilated pupils, increased heart rate and blood pressure
HPPD: distressing hallucinations following drug use →profound tolerance

Question 5

LHM

Answer 5

not a hallucinogen but a 5-HT2a agonist
biased agonist - selective for beta-arrestin pathway

Question 6

Psilocybin

Answer 6

structural homology to serotonin
euphoria, hallucinations, distorted perception
nausea and panic attacks
prodrug → psilocin: partial agonist at 5-HT receptors (high affinity at 2b/c, low at 2a)

Question 7

Dissociative Hallucinogens

Answer 7

distort perception = depersonalization, analgesia (ex. NO)

Question 8

Phencyclidine (PCP)

Answer 8

NMDA receptor antagonist - blocks glutamate signalling
inhibitor of dopamine transporter = increases levels of synaptic dopamine - addiction
changes in body image, loss of ego boundaries, paranoia, depersonalization

Question 9

Deliriant Hallucinogens

Answer 9

induce state of delirium = extreme confusion, loss of control
low lucidity: hallucinations are perceived as real - not aware of drug-altered consciousness
block muscarinic acetylcholine receptors (anticholinergics)
first generation anti-histamines are anticholinergics and have hallucinogenic effects at high doses

Question 10

Scopolamine + Atropine

Answer 10

tropane alkaloids - competitive antagonists at cholinergic receptors
delirium, confusion, hallucinations, loss of consciousness
dry mouth, muscle stiffness

Question 11

Oneirogens

Answer 11

produce dream-like state of consciousness (similar to REM)
REM - higher cortical rhythms than the rest of sleep (~5Hz)

Question 12

Salvia divinorum

Answer 12

Salvium A - agonist at kappa opioid receptor
short lasting hallucinations - immersive, low lucidity
includes features of classical psychedelics (visual imagery), dissociative hallucinogens (depersonalization + derealization), and deliriant hallucinogens (low lucidity)