Wake Up and Smell the Caffeine BiologyPsychology 3506
Wake Up and Smell the Caffeine Biology/Psychology 3506 12/14/2021 Caffeine 1
Introduction • The most popular psychoactive drug in North America • How many people here DO NOT ingest caffeine? 12/14/2021 Caffeine 2
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Introduction • That includes: • • 12/14/2021 Coffee 130 mg Tea 40 mg Soft Drinks (colas) 30 – 90 mg Cold and Headache medications 15 – 50 mg Red Bull 30 mg/100 mg (about 150 mg in a large can) Chocolate! 50 – 100 mg Wake up pills 100 – 500 mg Caffeine 4
Introduction • Almost always taken orally, absorbed in small intestine. • Crosses all barriers • Absorbed more slowly from cold beverages • Less than 2% is excreted 12/14/2021 Caffeine 5
Metabolism • Half life is between 30 min and 3. 5 hr • Metabolism slowed by birth control pills • Sped up by broccoli! • 2 x faster in smokers 12/14/2021 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 12/14/2021 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 12/14/2021 Caffeine 8
Neurophysiological Effects • Might cause release of epinephrine • Causes smooth muscles to relax, striate muscles to contract • Decreases airway resistance • Good for asthma, colds • Constriction of blood vessels to the brain • Dilation other places 12/14/2021 Caffeine 9
Neuropshysiological Effects • Not sure if it helps performance • Does reduce drowsiness, boredom. • Increases FA levels, could be performance enhancing, especially for long athletic events. • Controlled substance. • Increases time in light sleep • Stages 1 and 2 • Can counteract barbiturates. 12/14/2021 Caffeine 10
Effects on Nonhumans • Small doses increase SMA • Large doses do the opposite • Increases FR responding • Affects timing • Increases suppressed behaviour. • Generalizes to coke, not to amphetamine. 12/14/2021 Caffeine 11
But, how does that first cup make you feel? • Humans are great at discriminating • 1. 8 mg, about a sip of coffee!! • Caffeine makes us: • Energized • Focused • Motivated • Same in non users • All at low-moderate doses (20 -200 mg) • About a cup of coffee. 12/14/2021 Caffeine 12
Could I ever use a coffee • Tolerance • Sustained use leads to more adenosine receptors • Whole deal changes if big dose given to non users. • Withdrawal • Headache • Flu like symptoms • Bad attitude in general • 100 mg a day, most all of us! 12/14/2021 Caffeine 13
Reinforcing Properties • Hard to get animals to self-administer • Will prime cocaine use • Lots of variation in us • Task demands • Caffeine experience. • Demand is relatively inelastic. • Late 1970 s, 6 bucks a pound. 12/14/2021 Caffeine 14
Bad Stuff • Cancer? • Caffeinism • OD? • 30 -80 cups of coffee • Reproduction • Chromosomal damage? • Toxicity • Cardiac effects? • Depends on method 12/14/2021 Caffeine 15
Beware the International Coffee Conspiracy! 12/14/2021 Caffeine 16
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