Week 12: Cannabinoids & Psychedelics

Question 1

Main psychoactive substance of cannabis

Answer 1

9-tetrahydrocannabinol (9-THC)

Question 2

Marijuana absorption rate through inhalation

Answer 2

• Peak = almost instantaneous
• Lungs –> absorbed through bloodstream
• Duration = 4 hrs

Question 3

Marijuana absorption rate through mouth

Answer 3

• Peak = ~30-mins to 2 hrs
• ~30% absorbed/metabolized
• Slow absorption = slower effects
• Duration = 8 hrs

Question 4

Endocannabinoids

Answer 4

• Endogenous (derived internally) NTs that activate cannabinoid receptors

PRIMARY ENDOCANNABINOIDS
- Anadamide
- 2-archidonoyl-glycerol (@-AG)

Question 5

Retrograde NTs

Answer 5

Postsynaptic cell produces & releases into synapse
- Binds to presynaptic

Question 6

CB1 receptor targets

Answer 6

MOSTLY CNS
- Motor activity
- Thinking
- Motor coordination
- Appetite
- Short term memory
- Pain perception
- Immune cells

Question 7

CB2 receptor targets

Answer 7

MOSTLY PNS
- Gut
- Kidneys
- Pancreas
- Skeletal muscle
- Bone
- Eye
- Tumours
- Reproductive system
- Immune system
- Skin
- Cardiovascular system
- Liver

Question 8

Cannabinoid receptor agonists

Answer 8

• Mimic actions of endocannabinoids/THC
• Evoke same reduction in inhibitory currents caused by depolarization-induced suppression of inhibition
• Depolarization-induced suppression of inhibition could be prevented by cannabinoid receptor antagonists

Question 9

Cannabinoid receptors are ______ receptors

Answer 9

G-protein-coupled

Question 10

CB1 receptor activity

Answer 10

• Activated by AEA and 2-AG
• Inhibits: cAMP accumulation, voltage-gated Ca+ channels, K+ channels, NT release in presynaptic excitatory & inhibitory synapses

Question 11

CB1 receptors are largely _______

Answer 11

Pre-synaptic

Question 12

CB1 receptor activation leads to _____ dopamine concentrations in the ____ ______

Answer 12

Increased; nucleus accumbens
- High CB1 agonist = increase dopamine in nucleus accumbens
- Decrease CB1 antagonist = decrease glutamate in nucleus accumbens

Question 13

Reduced ___ ___ occurs in CB1 receptor knock-out mice

Answer 13

Reduced food

Question 14

Behavioural effects of cannabinoids

Answer 14

• Mild memory deficits
• Lower activity in hippocampus and DLPFC (dorsolateral)
• Impair motor coordination and muscle tone

Question 15

Long-term cannabis use

Answer 15

• Lower hippocampus and DLPFC activity (linked to memory)
• Decrease concentrations of acetylcholine and GABA in hippocampus
• Glutamate neurons from the hippocampus release less glutamate in structures

Question 16

Subjective effects

Answer 16

• Buzz, high, stoned
• Fater passage of time
• Suspiciousness and paranoia (changes in PFC = less synaptic density/efficiency)
• Apathy, lethargy
• Effortful task seem less effortful

Question 17

Cannabis and drug-discrimination procedures

Answer 17

• Only 9-THC produced 9-THC appropriate responding

Question 18

Exposure to cannabinoids is known to result in ____ _____

Answer 18

CB1R downregulation = lower lvls of CB1 expression)

Question 19

Medical uses of cannabis

Answer 19

• Autoimmune disease, cancer, epilepsy, glaucoma, neuropathic pain, unhealthy weight loss

Question 20

Psychedelic drugs

Answer 20

• Induce reality-altering experience, consisting of hallucinations, sensory distortions, delusions

Question 21

Hallucinogens

Answer 21

• LSD, psilocybin, mescaline, and dimethyltryptamine
• True: Perception of images/sounds that aren’t real
• Pseudo-hallucinations: Altered perception of things that are real

Question 22

Absorption of LSD

Answer 22

• Normally orally (ex. paper holds acid & absorbed into mouth)
• Peak after ~60 mins
• Cells in liver metabolize LSD –> 2-oxo-3-hydroxy-LSD
• Last 6-12 hrs
• Half-life of 3 hrs

Question 23

LSD pharmacodyanmics

Answer 23

• Activates both 5-HT1A and 5-HT2A receptors in visual cortex = modify visual processes
• Increased glutamate release through 5-HT2A activation

Question 24

Brain activity w/ LSD

Answer 24

• Visual cortex became more active w/ rest of brain
• Blood flow to visual regions increased (believed to be correlated w/ hallucinations)

Question 25

Default mode network (DMN)

Answer 25

Network interacting brain regions that is active when a person isn’t focused on the outside world