Can Ach cross BBB?

Discussion in 'Step I' started by path800, 05.20.14.

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  1. path800

    path800

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    Met an UW q asking what cannot be relived after organophosphate poisoning pt treated with atropine. And the answer is N Ach R's effect. But I am wondering some CNS effect caused by M1 R, eg seizure, can be relived by atropine?

    Sorry the title is actually asking can atropine cross BBB?
     
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  3. Diggidy

    Diggidy 7+ Year Member

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    https://en.wikipedia.org/wiki/Atropine

    Look at its chemical structure -- do you think it can cross? I would tell you, but I think it's an important thing to understand for boards and beyond, what qualities of compounds allow or don't allow it to cross the BBB.
     
  4. path800

    path800

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    thank you
    forget to check the structure
     
  5. tantacles

    tantacles Lifetime Donor SDN Moderator 7+ Year Member

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    How would it possibly have an effect on pupillary function if it couldn't cross?
     
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  6. Diggidy

    Diggidy 7+ Year Member

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    If you're talking about an eye dilation at the ophthalmologist, that's because it's applied topically.
     
  7. tantacles

    tantacles Lifetime Donor SDN Moderator 7+ Year Member

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    Nope, I'm talking about overdose. Overdose causes mydriasis.
     
  8. path800

    path800

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    I checked again. Seem atropine can cross BBB.
    I am not that chemical person but the atropine chemical structure contains a double bond (=O) which may change the polarity of the molecule.
     
  9. Ismet

    Ismet PGY-fun SDN Administrator 5+ Year Member

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    Yeah atropine can cross the BBB.
     
  10. tantacles

    tantacles Lifetime Donor SDN Moderator 7+ Year Member

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    Or we can just chalk it up to the fact that it's small.

    Honestly, what specific hypothetical molecules will and won't cross the BBB is not within the scope of what we need to know. Generally, the ones that can are small and nonpolar. However, think about the side effects of drugs - if a drug has neuro side effects, that often means it's crossing.
     

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