Reflection on Friday- Dopamine

“Because you are alive, everything is possible.” Thích Nhất Hạnh

“Keep swinging.” Hank Aaron

Dopamine is Important:

  • Dopamine has the chemical structure of 3,4-dihydroxyphenethylamine and is a member of the catecholamine and phenethylamine families.
  • Dopamine is a neurotransmitter, which means it delivers a message in the central nervous system. The enzyme L-DOPA decarboxylase removes carbon dioxide from levodopa (L-DOPA) to give dopamine (see picture below).
  • As a neurotransmitter in the brain, dopamine has many key physiological functions that include movement, cognition, reward/pleasure/motivation, attention, sleep, and sadly, it has a role in psychosis/addiction.
  • To replace the dopamine missing from each person-with-Parkinson’s, we typically take Levodopa along with Carbodipa. What is Carbidopa/Levodopa?
  • Interestingly, the blood-brain barrier (BBB) will not easily allow dopamine to enter the brain, but the immediate precursor of levodopa (L-DOPA) is allowed access to the brain.
  • Carbidopa is an enzyme inhibitor that prevents the processing of levodopa to dopamine in the peripheral tissue (which is not good). The BBB blocks entry of carbidopa to the brain.
  • Levodopa/Carbidopa provides the spark to positively fire the motor neurons for better movement, posture, balance, and coordination in Parkinson’s.

Also see these blog posts:
Treating Parkinson’s with a Dopamine Agonist: The Ropinirole Taper
Dopamine Agonists and Impulse Control Disorders in Parkinson’s
Purple Haze of Parkinson’s: How Dopamine Works

Cover photo image by Dimitris Vetsikas from Pixabay

Quote photo image by Jennifer Bazan-Wigle and Frank C. Church

2 Replies to “Reflection on Friday- Dopamine”

  1. Frank, I am grateful for all you do! You often inspire me when I most need it. Thank YOU! Your page on “hope”. made my day today. I have Parkinson’s ((mod. to quite severe) but feel well and whole. I have a comprehensive background in research methods. I am doing some “down on the farm” type research into the levodopa/carbidopa mix and have a burning desire to share my “observations” with someone who also suffers but has an open mind yet is deeply invested in Western Medicine. Anything you can help me with would be most appreciated. For instance, you write on this page, “Carbidopa is an enzyme inhibitor that prevents the processing of levodopa to dopamine in the peripheral tissue (which is not good)” I know it helps in the GI tract but where else and what type damage?…Please tell me more…you can make it as scientific as you wish (not that I am at your level) but scientific facts are like brain teasers for me. —-like some people do sudoku!! Blessing of the holiday season to you and yours. I pray that you have a safe place to go to to weather these scary and turbulent times!
    Warm Regards, Judy

    Liked by 1 person

    1. Judy, thanks for your note, I appreciate it greatly. One of my buddies replied recently to me that as we age our blood barrier gets leaky. In its original use, levodopa, but not carbidopa, penetrated the blood brain barrier. One possible explanation for increased need for levodopa/carbidopa as we age could it be related to this leaky barrier? If true, carbidopa may get to the brain and inhibit the enzyme that converts levodopa to dopamine. I have many thoughts about this hypothesis, it is intriguing and believable, but I’m not ready to write anything yet because I’ve got much to learn yet about this basic process. One day in the future for sure. Hope you too are safe during this new upswing of COVID-19? Best wishes, Frank


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