Caffeine Flashcards
What are the main effects of caffeine?
Recreationally – caffeine increases attention, learning/memory, mood, sociability, endurance, and motivation
Caffeine tolerance
chronic caffeine intake can lead to development of tolerance, leading to escalating caffeine intake
Can you have withdrawal from caffeine?
can produce withdrawal symtpoms
Is caffeine/nicotine a stimulant?
produce similar effects to stimulants, but act on different receptors
Pharmacodynamics of caffeine
caffeine works by antagonizing A-1 and A-2a adenosine receptors; these receptors (primarily A-1) are found presynaptically on many terminal boutons.
What is the role of adenosine?
Adenosine binds to A-1 receptors, which activate 2nd messenger signals that increase K+ efflux and decrease Ca2+ influx. Both events decrease exocytosis for many kinds of synapses.
Are adenosine receptors ionotropic or metabotropic?
They are metabotropic
Potassium shunt
a mechanism by which the terminal button can block the action potential. As soon as sodium goes in, potassium goes out, instead of waiting for the action potential to reach a peak.
Adenosine’s role in one sentence
dampens synaptic transmission
How are caffeine and adenosine related?
Caffeine BLOCKS adenosine receptors, by doing this, we see an increase in neurotransmitter release.
Role of neuroepinephrine
Neuroepinephrine is highly responsible for arousal/attention
Where are A-1 receptors found in high concentration?
Hippocampus, striatum, septum, frontal and cingulate cortex
What is a high dose of caffeine?
~500 mg at once, caffeine can induce hallucinations, paranoia, mania, or depression
caffeine overdose
caffeine is less potent on brainstem, between 2-10 cups of coffee required to get a state of shortness of breath, anxiety, agitation, and racing heart.
Is caffeine potent on the spinal cord?
No, caffeine is not very potent on spinal cord; need to ingest 20-30 cups of coffee to produce tremor/seizures
