Download Document

Wake Up and
Smell the Caffeine
Psychology 2800
5/23/2017
Caffeine
1
Introduction


5/23/2017
The most popular psychoactive
drug in North America
How many people here DO NOT
ingest caffeine?
Caffeine
2
5/23/2017
Caffeine
3
Introduction

5/23/2017
That includes:
 Coffee 130 mg
 Tea 40 mg
 Soft Drinks (colas) 30 – 90 mg
 Cold and Headache medications
15 – 50 mg
 Rev ?, probably about 100 mg
 Chocolate! 50 – 100 mg
 Wake up pills 100 – 500 mg
Caffeine
4
Introduction




5/23/2017
Almost always taken orally,
absorbed in small intestine.
Crosses all barriers
Absorbed more slowly from cold
beverages
Less than 2% is excreted
Caffeine
5
Metabolism


Half life is between 30 min and 3.5
hr
Metabolism slowed by birth control
pills
Sped up by broccoli!
 2x faster in smokers

5/23/2017
Caffeine
6
Metabolism


That was with adults (well not kids
anyway)
Different deal in kids and infants
85% excreted
 4 DAY half life
 Different pathways and metabolism
than in adults
 More similar to non-humans

5/23/2017
Caffeine
7
Neurophysiological
Effects.


Like alcohol, we don’t know!
Might block adenosine
Neuromodulator that inhibits firing
 So, caffeine disinhibits?
 High doeses block benzodiazipine
receptors

5/23/2017
Caffeine
8
Neurophysiological
Effects



Might cause release of epinephrine
Causes smooth muscles to relax,
striate muscles to contract
Decreases airway resistance



5/23/2017
Good for asthma, colds
Constriction of blood vessels to the
brain
Dilation other places
Caffeine
9
Neuropshysiological
Effects

Not sure if it helps performance


Increases FA levels, could be
performance enhancing, especially
for long athletic events.


Does reduce drowsiness,boredom.
Controlled substance.
Increases time in light sleep
Stages 1 and 2
 Can counteract barbiturates.

5/23/2017
Caffeine
10
Effects on Nonhumans



Small doses increase SMA
Large doses do the opposite
Increases FR responding



5/23/2017
Affects timing
Increases suppressed behaviour.
Generalizes to coke, not to
amphetamine.
Caffeine
11
But, how does that first
cup make you feel?

Humans are great at discriminating


Caffeine makes us:





Energized
Focused
Motivated
Same in non users
All at low-moderate doses (20-200 mg)

5/23/2017
1.8 mg, about a sip of coffee!!
About a cup of coffee.
Caffeine
12
Could I ever use a coffee

Tolerance



Withdrawal




5/23/2017
Sustained use leads to more adenosine
receptors
Whole deal changes if big dose given to
non users.
Headache
Flu like symptoms
Bad attitude in general
100 mg a day, most all of us!
Caffeine
13
Reinforcing Properties



Hard to get animals to selfadminister
Will prime cocaine use
Lots of variation in us
Task demands
 Caffeine experience.


Demand is relatively inelastic.

5/23/2017
Late 1970s, 6 bucks a pound.
Caffeine
14
Bad Stuff



Cancer?
Caffeinism
OD?


30-80 cups of coffee
Reproduction
Chromosomal damage?
 Toxicity


Cardiac effects?

5/23/2017
Depends on method
Caffeine
15
Beware the International
Coffee Conspiracy!
5/23/2017
Caffeine
16