Caffeine & Methylxanthines

What is caffeine

drug that is in the methylxanthine class; stimulant drug

What are the types of methylxanthines?

caffeine

theobromine

theophylline

When were methylxanthines first isolated from coffee?

1820

Coffee origin

East Africa (Ethiopia)

2 types of coffee

arabica

robusta

Where are arabica and robusta found?

seed of coffee tree berry

how much tap water in NA and Europe is used for coffee and tea production?

1/3

Coffee is the __________ most traded product in the world

2nd

Where is tea from?

African origin

now farmed in south america (tea tree)

What are the three types of tea

black

oolong

green

Black Tea

fermented and oxidized leafs of camellia sinensis

oolong tea

semifermented tea leafs of camellia sinensis

green tea

unfermented leaves of camellia sinensis

white tea

young, unfermented leaves (type of green tea)

What is herbal tea?

infused water

what gives tea its scent?

flower petals

tea contains what methylxanthines?

caffeine

theophylline

theobromine

cocao is from where?

farmed in Africa

Amazon origin

cacao makes what?

chocolate (cocoa)

What are the 2 methylxanthines found in cocoa?

caffeine

theobromine

(4) other natural sources of methylxanthines

ilex plant

guarana

cola

cassina

ilex plant

aka holly

found in Amazon region

used to produce Yerba Mate

Guarana

found in Amazon

2-6% caffeine content

What is the most potent natural source of caffeine?

Guarana

Cola

found in Southern Nigeria

nut that can be chewed

Cassina

found in S America

used to produce Youpon or black tea

Foods/drinks that contain methylxanthines

cola beverages

pudding mixes

baked goods

dairy desserts and candy

medicines that contain methylxanthines

headache meds

weight control aids

allergy relief compounds

stimulants

asthma meds

History of coffee

first use in Ethiopia (12-15th centuries)

spread through Europe in 1650 with the founding of coffeehouses

long association with politics and intellect

History of Tea

first use in China (780 AD)

introduced to Europe in 1600s

Boston Tea Party (1773) - no taxation without representation

Cocoa History

first use by Mayas, Aztecs, Incas in Pre-Columbia - mixed with psychedelics

Montezuma had 50 glasses/day

Cortes took it to Spain in 1520 and kept in a secret for 100 years

1st chocolate factory in England 1728

Route of admin

orally

rectal suppository

intramuscular or intravenous

Absorption

lipid soluble

mostly absorbed in intestines

caffeine peak

30-60 mins

distribution

crosses blood brain barrier and placental barrier

excretion

2% excreted unchanged

half life of caffeine

2.5-4.5 hours

the half life for theophylline and theobromine is (longer/shorter) than caffeine.

longer

caffeine metabolism

individual differences based on genetic enzymes

smokers eliminate 2x as fast

slowed during pregnancy

infants cannot metabolize well

caffeine metabolism slowed by

alcohol

NTs

blocks adenosine receptor —> inhibits release of GABA —> stimulates release of dopamine

Adenosine

inhibitory neuromodulator that slows everything down

neurophysiology

reduces spontaneous firing across brain

removal of GABAnergic inhibition

stimulates release of epinephrine and other catecholamines

high dosage effects

blocks benzodiazepine receptors

causes anxiety

Anandamide-like effects

chocolate stimulator of cannabinoid receptors

effects on body

stimulates sympathetic NS

epinephrine release from adrenal gland

bronchial dilation

vasoconstrictor in brain

what can methylxanthines be used to treat?

asthma and headaches

effects on human performance and behavior

increases perception and performance (depending on dose, time of consumption, and nature of task)

improves athletic performance

increases visual sensitivity, reaction time, driving

methylxanthines work best to increase performance when…

the performance is degraded by fatigue

effects on sleep

insomnia

wake up more easily

effects on unconditioned behavior of nonhumans

spontaneous motor activity

automutilation

effects on operant and respondent behavior of nonhumans

increases responses to negative and punished stimuli

increases avoidance responding (similar to amphetamine)

methylxanthines are generalized to what drug at low dosage?

cocaine (DA blockers block low dose discrimination)

subjective effects

feelings of well-being, alertness, energy, motivation for work, self-confidence

subjective effects at low doses

more positive effects

subjective effects at high IV doses

mistaken for cocaine

tolerance

increases generation of adenosine receptors

chronic treatment moves DR curve 6x

subjective effects tolerated within 4 days

withdrawal

decrease in locomotor activity

can resolve in a few weeks

causes headaches, drowsiness, decreased energy, lethargy

onset of withdrawal symptoms

12-28 hours

how long do withdrawal symptoms last?

2-9 days

Self-Admin in Humans

caffeinated coffee and capsules are reinforcers

primarily admin to avoid withdrawal symptoms

task-dependent use

caffein dependence syndrome

withdrawal, tolerance, desire to quit, use with health problems

population studies

most valuable commodity after oil

70mg consumed/person/day

North American consumption

>200 mg/person/day

harmful effects on reproduction

reduces blood flow to baby

lowers birth rate

found in breast milk (not good for infants)

harmful effects

cardiac disease (increased BP)

anxiety disorder (panic)

cancer?

bone density (loss in postmenopausal women)

possible lethal effects

lethal dose = 3-8g (30-80 cups of coffee)

convulsions and respiratory collapse