18: Psychoactive Plants (Stimulants)

Question 1

What are Stimulants?

Answer 1

Drugs that increase central nervous system activity

Examples: Cocaine (high-efficacy), Nicotine, Caffeine (both low-efficacy)

Question 2

Alkaloids

Answer 2

Cocaine, nicotine, and caffeine = alkaloids from tropical plants

Question 3

Alkaloids often affect?

Answer 3

The Nervous System

Question 4

Synaptic Transmission (Stimulants)

Answer 4

Neurons communicate via synapses using neurotransmitters

Stimulants can:

• Bind to post-synaptic receptors
• Block re-uptake of neurotransmitters → increases their concentration in the synaptic cleft

Question 5

Cocaine’s Mechanism

Answer 5

Blocks dopamine and norepinephrine transporters

Leads to heightened arousal, reward, attention, motivation

Question 6

Caffeine’s Mechanism

Answer 6

Blocks adenosine receptors (which normally inhibit norepinephrine)

Result: increased norepinephrine → wakefulness

Question 7

Nicotine’s Mechanism

Answer 7

Binds to nicotinic receptors (ionotropic, named after nicotine)

Mimics acetylcholine, triggering stimulation

Question 8

Coca Plant (Erythroxylem coca): uses ?

Answer 8

Traditional Uses in Andes: chewing leaves, coca tea

Used ceremonially and spiritually

Chewed with calcium carbonate to form freebase cocaine → easier absorption

Use dates back 3,000–8,000 years

Question 9

Cocaine History

Answer 9

Extracted in 19th century

Used as local anaesthetic

Forms:
- Cocaine hydrochloride (powder)

• Freebase cocaine (crack) – made by removing the salt form using a base

Question 10

Coca-Cola Origins:

Answer 10

Invented in 1886

Original ingredients: Coca leaf extract + Kola nut (caffeine)

Cocaine removed by 1903

Question 11

Tobacco (Nicotiana tabacum): Origins ?

Answer 11

Domesticated in the American tropics

Indigenous uses: spiritual, medicinal, recreational

Spread to Europe, became economically valuable

Question 12

Coffee (Coffea arabica & canephora): Origins?

Answer 12

Origin: Ethiopia

Spread to Arab world → Europe

Coffeehouses = centers for social, intellectual exchange

Question 13

Identify three mechanisms by which stimulants affect synaptic transmission.

Answer 13

Stimulants can:
(1) increase neurotransmitter release,
(2) block reuptake,
(3) mimic neurotransmitters at receptors.

Question 14

Name two neurotransmitters whose reuptake is blocked by cocaine and describe the behavioural effects.

Answer 14

Dopamine – causes euphoria and addiction.
Norepinephrine – increases arousal and alertness.

Question 15

Name two stimulant crops that were part of the Columbian Exchange.

Answer 15

Tobacco and coffee

Question 16

How are stimulants like coffee and tobacco linked to colonialism and global labour exploitation?

Answer 16

Cultivated on plantations using enslaved or exploited labour; profits fueled European colonial economies.