Caffeine Flashcards
What kind of chemical is caffeine?
- in the group of methylxanthines
- which is in the group of alkaloid
Where are alkaloids naturally found?
- in plants and the human body
- subcomponent of many organic compounds
- lipid soluble
How is caffeine processed in the body?
- caffeine breaks down to theophylline and theobromine which breaks down to paraxanthine
What are the active metabolites of caffeine?
- theophylline
- theobromine
- paraxanthine
What are the metabolites of caffeine structurally similar to?
- serotonin
- histamine
- dopamine
- (glutamate)
What is a neuromodulator?
- a chemical used by a neuron to communicate to other neurons about their function
- regulate gene expression and set points
What is adenosine?
- a neuromodulator
What effect does adenosine have?
- inhibitory effect
- sleep/arousal
- cognition and memory learning
Where does adenosine act to influence sleep and arousal?
- striatum
- glutamate antagonist
Where does adenosine act to influence cognition and memory/learning?
- hippocampus
- dopamine antagonist
How does caffeine affect adenosine?
- adenosine antagonist for A1 receptors
What function are the adenosine A1 receptors involved in?
- slowing metabolic function via a retrograde messenger and postsynaptic depression of NMDA receptor
What functions are NMDA receptors involved in?
- memory, synaptic plasticity
- hebbian learning
If caffeine is an adenosine antagonist, what does this effect/result in?
- caffeine inhibits adenosine receptors which results in facilitation of memory and synaptic plasticity
What are the two negative effects of caffeine?
- hyperactivation results in inability to focus
- constriction of vasculature in the brain results in migraines
What are both adenosine A1 and A2a receptors involved in?
- oxygen in blood flow
- reduced heart rate
Why are caffeine and theophylline used to avoid hypoxia?
- because they are antagonists to A1 and A2a receptors which then stimulates respiration
What are the three new points of research in regards to caffeine and adenosine?
- opens BBB: caffeine limits permeability
- A3 can inhibit melanoma cells: caffeine interferes
- A2a: anti-inflammatory agent: caffeine allows inflammation
What are the general behavioural effects of caffeine?
- mood elevation
- performance enhancement
What explains the mood elevation effects of caffeine?
- “placebo”: dopaminergic release
- emotional attribution: James-Lange theory
What explains the performance enhancement effects of caffeine?
- enhances boring or simple tasks (not complex tasks)
- impairs decision making in physical tasks
- decreases fatigue
What is a common misconception of the effects of caffeine?
- it is not sobering like many people believe
- alertness is misattributed
Absorption and elimination of caffeine are?
- highly variable
Why is caffeine dose-dependent?
- developmental stage (children need more)
- time to peak does not change across doses (gate/binding mechanism)
How is caffeine affected in the presence of sugars?
- concentration levels/time decreases
How does experience affect caffeine?
- more experience results in longer times
Does caffeine have observable tolerance and withdrawal?
- can observe physiological effects but not the psychological effects
- research does not find consistent patterns of withdrawal
What is the problem with studying tolerance and withdrawal from caffeine?
- variability of absorption
- poor operationalization of dosage
- individual differences
- small rates
What are the three conditions that qualify a “caffeine use disorder” by the DSM-V?
- tolerance
- withdrawal
- desire to quit/control use but continuing to use
Is caffeine safe by the FDA standards?
- “generally regarded as safe”
- 10 grams would be toxic (57 cups of coffee)
What are energy drinks a combination of?
- xanthine
- potentiators
What are the problems with energy drinks?
- advertised as low caffeine
- comparable potencies unknown
- timing (excitotoxicity and kindling)
How can energy drinks be advertised as low caffeine?
- highly variable xanthine content
- caffeine listed if added but not if naturally occurring
- metabolites, precursors and compounds not measured
What is an example of a naturally occurring potentiator and xanthines?
- potentiator: panax ginseng root
- xanthines: guarana seed
What is taurine?
- similar to GABA
- neuroprotectant
What is GABA?
- inhibitory in adults
- excitatory in children
- anxiolytic effects
- antero/retrograde amnesia
What is the problem with consuming taurine?
- it is similar to GABA
- exitotoxicity and developmental effects
- boycotts natural warning mechanism by anxiolytic effects
- boycotts learning mechanism
What is a neuroprotectant?
- inhibits glutamate-induced excitotoxicty
- trophic and inhibitory modulator
- altered in neuropsychiatric disorders
- antioxidant/prevent oxidative stress
What are the effects of caffeine and taurine together?
- synergistic effects (caffeine potentiated)
- accuracy decreased and reaction time increased
- “aerobic” heart pattern (potential stress)
- potential increase in mood (feel less ill/negative)
