19: Opium and Cannabis

Question 1

What are the 4 key steps in pain perception?

Answer 1

1. Transduction – Injury causes chemicals to activate pain receptors (nociceptors).
2. Transmission – Signals travel from nerves to brain using neurotransmitters like glutamate.
3. Modulation – The brain can increase or reduce pain signals using substances like endorphins.
4. Perception – Brain becomes aware of and interprets the pain.

Question 2

What happens during transduction?

Answer 2

Cell damage causes release of chemicals like histamine → stimulates nociceptors → action potential is generated.

Question 3

How is pain transmitted?

Answer 3

Neurotransmitters (e.g., glutamate, substance P) carry signals to the brain.

Question 4

How does the body modulate pain naturally?

Answer 4

Endorphins bind to opioid receptors → reduce neurotransmitter release (pre-synaptic) and block signals (post-synaptic).

Question 5

What do endorphins do at the synapse?

Answer 5

Inhibit neurotransmitter release and block signal propagation.

Question 6

How do opioids mimic endorphins?

Answer 6

They bind to the same receptors (like MOR) to block pain signals.

Question 7

What’s the relationship between MOR, β-endorphins, GABA, and dopamine?

Answer 7

β-endorphins inhibit GABA → allows dopamine to increase → reward feeling.

Question 8

What are the 3 main Cannabis species and where are they from?

Answer 8

Cannabis sativa: tall, fibrous – Central Asia

Cannabis indica: bushier – Indian subcontinent

Cannabis ruderalis: small, fast-flowering – Russia/Europe

Question 9

What are glandular trichomes and what do they produce?

Answer 9

Hair-like structures on cannabis that produce cannabinoids, terpenes, flavonoids.

Question 10

How does THC affect the brain?

Answer 10

Binds to CB1 receptors → causes psychoactive effects.

Question 11

How does CBD differ from THC?

Answer 11

CBD is non-psychoactive and alters CB1 shape → reduces THC binding.

Question 12

What are the two main endocannabinoids?

Answer 12

Anandamide (AEA) – binds CB1;
2-AG – binds CB2 (immune system-related).

Question 13

What are bast fibres and where do they come from?

Answer 13

Strong fibres from plant inner bark – e.g., hemp, flax.

Question 14

How was hemp used historically (1600–1900)?

Answer 14

For rope, sails, clothing – important in shipping and industry.

Question 15

Why was Russian hemp dominant in the 1700s?

Answer 15

Cheap serf labour, strong fibre quality, export-driven economy.