Exam 2: Caffeine

Question 1

what is the most widely used psychoactive substance in the world?

Answer 1

caffeine

Question 2

caffeine

Answer 2

mild psychostimulant of Xanthine family

- found in many plants : originally evolved to protect plants from insects, bacteria, fungi

Question 3

where is caffeine found

Answer 3

coffees, sodas, some OTC medications

Question 4

where is theophylline found

Answer 4

tea

Question 5

where is theobromine found

Answer 5

chocolate

Question 6

what drink has the highest amount of caffeine vs the lowst

Answer 6

highest: coffee
lowest: tea

Question 7

Route of administration for caffeine

Answer 7

orally mostly

Question 8

absorption of caffeine

Answer 8

• completely absorbed from GI tract - in 30-60 min
• plasma half life: 4-6hrs
• repeated caffeine drinking throughout day inc plasma caffeine level gradually

Question 9

distribution of caffeine

Answer 9

throughout brain and body
NO accumulation within the body - no depot binding sites
readily passes through membranes like BBB

Question 10

metabolism of caffeine

Answer 10

broken down into 3 active metabolites

-paraxathine, theobromine, theophylline

Question 11

active metabolite that does lipolysis
- mobilizes stored energy in fat during fasting or exercise - why some people consume during weightloss
major metabolite

Answer 11

paraxathine

Question 12

metabolite that dilates blood vessels and inc urine production

Answer 12

theobromine

Question 13

metabolite that relaxes smooth muscles of bronchi - used to treat asthma
can cause nausea, irregular heartbeat

Answer 13

theophylline

Question 14

what 2 active metabolites of caffeine are found in tea and chocolate

Answer 14

theobromine and theophylline

Question 15

caffeine metabolism is slower if

Answer 15

men, pregnant women, newborns
used ith birth control pills
liver damage -since caffeine metabolized in liver
asian population

Question 16

caffeine is metabolized faster if

Answer 16

used with cigarettes
women, children
caucassian population

Question 17

excretion of caffeine

Answer 17

first order kinetics-exponential, half life
in urine:
- 95% as metabolites (mainly paraxathine)
-5% as unchanged in urine

Question 18

pharmacodynamics of caffeine: its diverse actions in brain

Answer 18

adenosine receptor antagonism!!!!
high doses:
- GABA A receptor antagonism
-inc in Ca within cells - more likely to fire action potential

Question 19

what is adenosine created from

Answer 19

breakdown of ATP
- astrocytes and neurons release energy carrying ATP molecules

or

as a byproduct in gluconeogenesis - glycogen to glucose

Question 20

what mobilizes glycogen from storage

monitors glucose levels, if low recruits it from storage

Answer 20

astrocytes

Question 21

4 receptor subtypes of adenosine and which mediate most adenosine effects in the brain - respond to caffeine

Answer 21

A1, A2A, A2B, A3

A1R and A2AR mediate most adenosine in the brain

Question 22

where are A2A receptors found

Answer 22

striatal GABAergic projecting neurons (indirect pathway)

and nucleus accumbens

Question 23

striatal A2A receptors form heteromers with what

Answer 23

dopamine D2 receptors - indirect pathway neurons

Question 24

A2A receptor occupancy by adenosine has what effect on the D2 receptor

Answer 24

allosteric influence

- reducing the sensitivity to dopamine decreasing arousal and altering the motor effects of dopamine

Question 25

caffeine is a ________ for metabotropic adenosine receptors

Answer 25

competitive antagonist

Question 26

blocking adenosine receptors...

Answer 26

enhances dopamine D2 receptor signaling - get mild arousal and psychomotor activation inc in movement by activating D2

Question 27

where are adenosine receptors found

Answer 27

heart and kidneys | - diuretics : inc the amount of water expelled form the body

Question 28

caffeine activates what nervous system and what does it cause

Answer 28

sympathetic nervous system coronary artery vasodilator and bronchodilation - inc HR - constricts cerebral arteries (inc BP) - inc respirations induces fight or flight when no stress

Question 29

benefits of caffeine

Answer 29

- daily consumption of 400mg poses little to no risky for healthy ppl - mental performance: inc alertness, attention, rxn time - physical performance: inc endurance, delayed fatigue - imprved migraine symptoms if take at onset - constricted blood vessels

Question 30

caffeine intoxication effects and level

Answer 30

more than 500mg a day - panic attacks, nausea, clumsinesss, restlessness, GI isturbances, insomnia, muscle twitching - heart palpitations, tachycardia, high BP, nausea, seizures, metabolic aciosis (kidney dysfunction

Question 31

can caffeine kill you? lethal dose?

Answer 31

LD50=150-200mg caffeine/kg bodyweight | calculate

Question 32

If you drink a big coffee (200mg) at 3pm, how much will still be in your system at 9pm, and when will it all be gone?

Answer 32

at 9pm: 100mg will be left | all gone: 6 half lives - for a halflife of 4 hours : 24 hrs for 6 hrs: 36 hrs

Question 33

when would you need to stop drinking coffee to ensure good sleep?

Answer 33

12pm

Question 34

caffeine with alcohol...

Answer 34

ethanol consumption increases adenosine | - makes you feel sleepy - drinking alcohol has sedative effects

Question 35

caffeine prevents the activation of what?

Answer 35

adenosine receptors - reduced fatigue masks sedative effects of alcohol

Question 36

what might slow down the clearance of alcohol from your system

Answer 36

zero order kinetics

Question 37

tolerance and caffeine

Answer 37

-chronic use leads to tolerance for subjective effects, cardiovascular and respiratory effects, disrupts sleep

Question 38

high doses of caffeine (750-1200mg/day) can produce

Answer 38

complete tolerance in some individuals | - no longer getting benefits from caffeine

Question 39

dependence and caffeine

Answer 39

mild seen in individuals chronically using >100mg a day NOT recognized as substance abuse by DSM-5

Question 40

withdrawal symptoms with caffeine

Answer 40

headache, fatigue, drowsiness, difficulty concentrating, irritability, depression, anxiety, impaired motor abilities, cognitive performance

Question 41

headaches and caffeine

Answer 41

in 1st week not many headaches but once first day of placebo there is a spike in headaches

Question 42

fatigue and caffeine

Answer 42

takes longer to stabilize over time than the headaches - 405 days