The Effect of Caffeine on Neurological Dopamine Production Process Dynamics & Control October 13 th, 2004 Student Name 1 Student Name 2

Presentation Outline Introduction Simulation Assumptions Process Outcomes  Laplace via Maple  Matlab  Simulink Conclusion

What is Caffeine? The most commonly used neurological drug worldwide trimethylxanthine, (C 8 H 10 N 4 O 2 ) bitter tasting white powder Retrieved from: caffeine-molecule.gif

Common Substances Coffee, tea, soft drinks, and pain medication Caffeine Content:  Brewed coffee: mg  Black Tea: mg  Excedrin: 65 mg  Mountain Dew: 55 mg  Green Tea: 8-36 mg

What is Dopamine? Neurotransmitter  Movement  Thought processes  Emotions  Pleasure “Rewards” centers of the brain Retrieved from:

The Relationship Between Caffeine and Dopamine Caffeine has ½ life of ~6 hours in a healthy person Enters Digestive tract  Some caffeine is lost in liver  Remainder enters bloodstream Caffeine enters the brain  Stimulates excessive dopamine release  Blocks uptake receptors

Ultimate Response:

Simulation Assumptions Body consists of 3 tanks  Stomach, Liver, and Brain Flow rates, tank volumes and density remain constant Dopamine production is a first order chemical reaction  Caffeine→Dopamine

Initial Conditions F1F1 25 dL/s F2F2 20 dL/s F3F dL/s F4F4 F5F dL/s k1k mol-dL -1 s -1 k2k mol-dL -1 s -1 VsVs 5 dL VlVl 4 dL VbVb 2 dL

Simulation Process C i,caf., F 1 Stomach: C 1, V s F 2, C 1 C 3, F 3, D 3 Liver: D 2, C 2, V l Brain: D 5, C 5, V b F 4, C 4, D 4 F 5, D 5 Caffeine Dopamine r b =k 1 C 5

Focus Amount of Dopamine produced as a function of input Caffeine

Mass Balances: Stomach C i,caf., F 1 Stomach: C 1, V s F 2, C 1 Equation 1. Stomach Mass Balance (Caffeine)

Mass Balance: Liver F 2, C 1 C 3, F 3, D 3 Liver: D 2, C 2, V l F 4, C 4, D 4 F 5, D 5 Equation 2. Liver Mass Balance (Caffeine) Equation 3. Liver Mass Balance (Dopamine)

Mass Balance: Brain Brain: D 5, C 5, V b F 4, C 4, D 4 F 5, D 5 Caffeine Dopamine r b =k 1 C 5 Equation 4. Brain Mass Balance (Caffeine) Equation 5. Brain Mass Balance (Dopamine)

Laplace Transform: Steady State S-Domain t-Domain =C i,caf { }

Caffeine Impulse Function

Caffeine Unit Step Function

Caffeine at Steady-State

Dopamine at Steady State

Dopamine Unit Step Function

Dopamine Impulse Function

Simulink Unit Step Function For Caffeine

Simulink Unit Step Function For Dopamine

Simulink Impulse Function for Caffeine

Simulink Impulse Function for Dopamine

Conclusion Achieved anticipated results in the theoretical process Possible differences in real process Suggestions Thanks to Dr. Rodgers

Questions?