The Effect of Caffeine on Neurological Dopamine Production

Process Dynamics & ControlOctober 13th, 2004Student Name 1Student 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, (C8H10N4O2) bitter tasting white powder

Retrieved from: www.cs.virginia.edu/.../ caffeine-molecule.gif

Common Substances

Coffee, tea, soft drinks, and pain medication

Caffeine Content: Brewed coffee: 40-180 mg Black Tea: 20-100 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: http://www.bip.bham.ac.uk/osmart/msctox/

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

F1 25 dL/s

F2 20 dL/s

F3 0.0001 dL/s

F4 0.0001 dL/s

F5 0.05 dL/s

k1 0.250 mol-dL-1s-1

k2 0.125 mol-dL-1s-1

Vs 5 dL

Vl 4 dL

Vb 2 dL

Simulation Process

Ci,caf., F1

Stomach: C1, Vs

F2, C1

C3, F3, D3

Liver: D2, C2, Vl

Brain:D5, C5, Vb

F4, C4, D4

F5, D5

Caffeine Dopamine rb=k1C5

Focus

Amount of Dopamine produced as a function of input Caffeine

)(5 iCfD

Mass Balances: Stomach

Ci,caf., F1

Stomach: C1, Vs

F2, C1

Equation 1. Stomach Mass Balance (Caffeine)

12,11 CFCF

dt

dCV cafis

Mass Balance: Liver

F2, C1

C3, F3, D3

Liver: D2, C2, Vl

F4, C4, D4

F5, D5

3344122 CFCFCF

dt

dCVl

4433552 DFDFDF

dt

dDVl

Equation 2. Liver Mass Balance (Caffeine)

Equation 3. Liver Mass Balance (Dopamine)

Mass Balance: Brain

Brain:D5, C5, Vb

F4, C4, D4

F5, D5

Caffeine Dopamine rb=k1C5

51445 CkCF

dt

dCVb

5255445 CkDFDF

dt

dDVb

Equation 4. Brain Mass Balance (Caffeine)

Equation 5. Brain Mass Balance (Dopamine)

Laplace Transform: Steady State

025.0105.2

105.20125.0

115.0

1075.3105.2

0125.01

025.0

0625.0

15.0

1075.3

105.2

5

4

5

)()('5

5

5

5

5

5

,5

sx

xssx

xs

ss

x

xsssCsD cafi

S-Domain

t-Domain

=Ci,caf{

}

Caffeine Impulse Function

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

25

30

35

40

45

time,seconds

conc

entr

atio

n,C

affe

ine

Caffeine Impulse

C in Stomach

C in LiverC in Brain

Caffeine Unit Step Function

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

25

30

35

40

45

time,seconds

conc

entr

atio

n,C

affe

ine

Caffeine Step Function

C in Stomach

C in LiverC in Brain

Caffeine at Steady-State

0 100 200 300 400 500 600 700 800 900 10000

5

10

15

20

25

30

35

40

45

time,seconds

conc

entr

atio

n,C

affe

ine

Caffeine at Steady State

C in Stomach

C in LiverC in Brain

Dopamine at Steady State

0 100 200 300 400 500 600 700 800 900 10000

10

20

30

40

50

60

70

time,seconds

conc

entr

atio

n,do

pam

ine

Dopamine at Steady State

D in Brain

D in Liver

Dopamine Unit Step Function

0 200 400 600 800 1000 1200 1400 1600 1800 20000

10

20

30

40

50

60

70

time,seconds

conc

entr

atio

n,do

pam

ine

Dopamine Unit Step Function

D in Brain

D in Liver

Dopamine Impulse Function

0 500 1000 1500 2000 25000

10

20

30

40

50

60

70

time,seconds

conc

entr

atio

n,do

pam

ine

Dopamine Impulse

D in Brain

D in Liver

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?