14: Hallucinogens Flashcards
Classical hallucinogens show some structural similarity to _____ and stimulate the _____ receptor.
Serotonin; 5-HT2A.
Hallucinogenic substances were used for hundreds of years for what purposes?
Religious ceremonies.
Hallucinogens that act via serotonergic receptors can be classified into what two main categories?
Tryptamines (e.g. psilocybin, LSD) and phenethylamines (e.g. mescaline).
Densest 5-HT2A receptors are localized where?
To layers IV and V of pyramidal cells of anterior cortex.
What is the onset of effect for LSD and duration of action? What is a distinct effect?
Effects typically begin within 30 to 90 minutes of ingestion and may last 12 hours.
Synesthesia, in which a person seems to hear or feel colors and see sounds.
Effects of psychosis-like sx in LSD are highly dependent on what? Why is clinical research difficult for LSD? What usually motivates usage?
Personality of drug-taker.
Unpredictability of effect and “bad” trips.
Curiosity and “self-discovery.”
Psilocybin effects are stronger within _____ alterations whereas ketamine more affects the _____.
Perceptual; control and cognition.
Provide three examples showing hallucinogens grant distinct effects.
Ketamine: largest increase in disembodiment.
MDMA: strong effects on blissful state and experience of unity.
Psilocybin: equipotent effect on blissful state and imagery.
Nearly all hallucinogens lack affinity for what? What does this suggest?
Lack affinity for DA receptors or for the DA uptake transport.
Therefore, do not directly affect DA transmission.
What is hallucinogen persisting perception disorder?
Re-experiencing one or more of the perceptual effects that were induced by hallucinogens, but occurring after effect of the drug has worn off or in complete absence of the drug. No treatment available.
Hallucinogens can induce the onset of psychosis or depression, which can sometimes led to suicide. What is the incidence rate for this?
8:10,000.
How do hallucinogens affect “head twitch” in rodents?
Direct and indirect 5-HT agonists induce this effect, 5-HT2 receptor antagonists selectively block the head twitch.
PCP-like drugs and NMDA receptor antagonists enhance 5-HT2A-receptor-mediated head twitch response.
What is PCP and how is it most commonly consumed? What are the dangers? What are disturbing side effects?
Phencyclidine: weak base that is lipid, water, and alcohol soluble.
Inhalation accounts for 70% of usage, because onset of action occurs in 2-5 minutes.
Doses greater than 10 mg usually result in comas. Most disturbing behavioral effects are violent, aggressive and bizarre behaviors with self-mutilation tendencies.
How effective is ketamine psychedelic therapy of alcoholism?
1 year: abstinence in 73/111 people.
2 years: 33/81 people.
3 years: 14/42 people.
What is Salvinorin A?
Does not act via 5-HT2A receptor stimulation, is the k opioid receptor selective agonist.
Induces depresssive-like behaviours.
