Neurotransmitters and Drugs

Discussion in 'Pharmacology' started by pharmapsyche, Jan 30, 2006.

  1. pharmapsyche

    pharmapsyche AKA Miss Methylene Titanium Member

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    Neurotransmitters and Drugs

    First I'll define what exactly neurotransmitters are and give you a example of a few:
    First of all, the primary monoamine neurotransmitters are Dopamine, Norepinephine, and Serotonin.

    Neurotransmitters are the chemicals which account for the transmission of singnals from one neuron to the next across the synapses within the brain. They are also found at the axon endings of motor neurons, which is where they simulate the muscle fibers to conctract.

    Neurotransmitters:

    Acetylcholine- Acetylcholine is imporant to know, becuase it was the first neurotransmitter to ever be discovered. It was first isolated in 1921 by the German biologist, Otto Loewi. Otto Lewoi actually later won the Nobel Prize for his discovery and hard work. Acetylcholine has many different functions such as, it is responsible for much of the stimulation of muscules, including the muscles of the gastro-intestinal system. It is also found in the sensory neurons and in the autonomic nervous system, and has a part in the schedule of REM sleep.

    Norepinephrine- Norepinephrine was discovered in 1946 by the Swedish biologist Ulf Von Euler, who also won a Nobel Prize for his work. Norepinphrine is strongly associated with bringing our nervous system into a 'high-alert'. It is prevalent in the sympathetic nervous system and it also increases our blood pressure along with our heart rate. Our adernal glands release it into our blood stream, along with it's colse relative adernalin. Norepinephrine is very important when it comes to forming memories. Amphetamines work by causing the release of Norepinephrine.

    Dopamine- Dopamine was discovered by the Swedish biologist Arvid Carlsson. It is an inhibitory neurotransmitter which means that when it finds its way to it's receptor sites, it then blocks the tendenct of that neuron to fire. Dopamine is strongly associated with the reward mechanisms in the brain. Drugs such as cocaine, opium, heroin,alcohol, and nicotine increase the levels of dopamine. Another thing to note is that schizophrenia has been shown to invlove excessive amounts of dopamine in the frontal lobes and drugs that block dopamine are used to help schizophrenics. But also, too little dopamine in the motor areas of the brain are the cause of the illness
    Parkinson's disease.

    Serotonin- Serotonin is mainly involved in emotion and mood. Too little serotonin has been shown to lead to depression, behavioral problems, obessive-compulsive disorder, and even suicide. Too little also leads to an increased appetite for carbohydrates and trouble sleeping. SSRI's, which are also known as Selective Serotonin Reuptake Inhibitors are drugs that help people with depression by preventing the neurons from taking up excess serotonin, so that there is more floating around in the synapses. An interesting fact is that a little warm mile before bedtime also increases the levels of serotonin. Serotonin also plays a role in perception. All hallucinogens, such as LSD-25 work by attaching to serotonin receptor sites.

    Drugs work on Neurotransmitters in one or more of these ways:
    1. Drugs can stop the chemical reactions that create neurotransmitters.
    2. Drugs can empty neurotransmitters form the vesicles where they are normally stored and protected from breakdowns by enzymes.
    3. Drugs can block neurotransmitters from entering or leaving vesicles.
    4. Drugs can bind to receptors in place of neurotransmitters.
    5. Drugs can prevent neurotransmitters from returning to their reuptake system
    6. Drugs can interfere with second messengers, the chemical and electrical changes that take place in a receiving neuron.
     
    Last edited: Jan 30, 2006
    1. 5/5,
      interesting, good info
      Jul 21, 2006
    2. 3/5,
      Nice, informative and concise post.
      Apr 13, 2006
    3. 3/5,
      Well researched girl!
      Feb 1, 2006
  2. Chaote

    Chaote Newbie

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    I was under the impression that there were two types of neuro transmitters, excitory and inhibitory and dopamine, seritonin.... were chemical sent to one of the types of neuro transmitters for the desired effect. Am I totally wrong?
     
  3. sands of time

    sands of time Gold Member

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    Chaote - I'm not sure exactly what you mean, but dopamine and serotonin are neurotransmitters, they bind with receptors by crossing the synapsis. That is how they work for the most part.

    Nice info Pharma
     
  4. fatmanstan

    fatmanstan Titanium Member

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    Here's a good slideshow from Dancesafe.org explaining the effects of ecstacy, showing how it, particularly, acts on the neurotransmitters in the brain.

    http://www.dancesafe.org/slideshow/index.html

    Many of you may have already seen this, but it is a very visual way of describing some of the actions mentioned above.

    (not sure if I can post links yet, just copy and paste the URL into the address bar)

    This Slideshow was created by Emanuel Sferios. Feel free to reproduce any or all of it at will. All we ask is that you credit Emanuel and DanceSafe. Emanuel can be contacted at at: [email protected]

    Mods: hope this isn't against the rules. I have read them, and I'm pretty sure it isn't. However, please feel free to delete if necessary.
     
    Last edited by a moderator: Sep 10, 2017
    1. 5/5,
      good info
      Aug 27, 2006
  5. pharmapsyche

    pharmapsyche AKA Miss Methylene Titanium Member

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    Chaote, you're right-on when you say there are two types of neurotransmitters: excitatory and inhibitory. Basically, a neurotransmitter can either cause a neuron to "fire" (cause depolarization inside of the neuron) or block a neuron from "firing" (cause hyperpolarization inside of the neuron.)

    Dopamine is a unique neurotransmitter because it is considered inhibitory yet causes depolarization in some instances... or something like that
     
  6. psyche

    psyche Palladium Member

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    Quite nice... I still feel it would've needed introduction of GABA. Gamma-aminobutyric acid is major inhibitory neurotransmitter wich functions almost everywhere on the brain. GABA-receptors are affected by alcohol, benzos and barbiturates for example. And Muscimol also, active ingredient in delerian Fly Agaric.
     
  7. Forthesevenlakes

    Forthesevenlakes Platinum Member

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    in response to chaote, most neurotransmitters fall under the categories of either inhibitory or excitatory. GABA I think should have been introduced as well, understanding the shape of the gaba receptor and how it functions allows one to see immediately why, say, mixing alcohol and benzos can be dangerous. Perhaps glutamate should have been introduced too, I cant think of many drugs offhand that affect glutamate levels, but I do know that DXM binds a type of glutamate receptor, among a few other things.
     
  8. sands of time

    sands of time Gold Member

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    Acetylcholine behaves the same way.
     
  9. psyche

    psyche Palladium Member

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    I think it would be good to have own section for neuropharmakology and brain.
     
  10. Richard_smoker

    Richard_smoker Gold Member

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    Glutamate is pretty damn important as well.

    It is THE excitatory neurotransmitter inside the brain. Why isn't it mentioned??? It's GABA's opposite.
     
  11. sands of time

    sands of time Gold Member

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    Glutamate is also the most abundently found neurotransmitter in the brain. Other than that, I don't know much about it actually. I'm assuming it's not given much attention here because it's not one of the primary pleasure neurotransmitters hehe.
     
  12. Richard_smoker

    Richard_smoker Gold Member

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    Yeah, you're right about being abundant. It's the primary activating NT in the brain; like GABA is the primary de-activating--or, maybe I should reword-->GABA decreases likelihood of axon transmission, slowing down the circuit, making you feel sedated, etc.

    But don't underestimate the power of glutamate. It is the end-result of activation by many drugs including amphetamine, cocaine, etc. Glutamate is the chemical which causes neurotoxicity from overload. It is also the mechanism by which benzo/alcohol withdrawal causes over-excitation neurotoxicity (brain-damage).

    By the way, Sandsoftime, I don't remember if I included this as a well recognized form of brain damage or not. Remember? In my 265 pg long reply to your question about drugs and brain damage??

    Well, regardless of whether or not i remembered to include it, glutamate toxicity is a well-known cause of withdrawal seizures, and worse--of a type of toxicity that can be thought of as a nerve cell self-destruction cascade. When 1 nerve dies, it loses its glutamate (and DNA and everything else) to its environment. Then that loose glutamate causes chaos in the neighboring cells, leading to toxicity and cell death, which causes more glutamate dumping from dead neurons, etc. Not a very pretty picture.
     
  13. Richard_smoker

    Richard_smoker Gold Member

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    Oh yeah! I totally forgot something REALLY important about Glutamate and NMDA receptors!

    Remember our old discussions about piracetam, nootropics, and other 'smart drugs'??

    Glutamate (and one of it's receptor: NMDA) is very important in memory circuits and it's what is affected by Piracetam, Ibogaine, and DXM. Here's a quote from my latest research into DXM as an Ibogaine replacement (posted under addiction and recovery)
    Hope this helps. I'm afraid that all this information is going to do is end up re-affirming how fucking complicated that the human brain actually is! Sorry if I've confused anyone. I can clarify if anyone wants. -RS
     
  14. sands of time

    sands of time Gold Member

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    So when one comes off extensive use of almost any drug, glutamate concentrations go through the roof? Many resources claim that opiate use is not neurotoxic, but what your saying conflicts with that. This does sound pretty ugly indeed. Could high glutamate levels result in symptoms such as anxiety?

    Another thing... Many doctors believe that Alzheimer's disease is caused, in part, from high levels of glutamate. Some medications work as NMDA antagonists, thus combating the effects of having such high levels of glutamate. As you have said, glutamate inflicts a great deal of damage to the brain in high amounts. It would be interesting to see how the damage caused by drug abuse compares to that of Alzheimers disease. It's also scary to see how Alzheimers disease is so sneaky.
     
  15. Richard_smoker

    Richard_smoker Gold Member

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    YES! This is probably the NUMBER 1 symptom!

    Neuronal Receptor Response May Help Explain Alzheimer's Memory Loss

    Georgetown University Medical Center; Science Daily. February 10, 2006

    Basically, this goes back to the finding that alzheimer's patients have plaques accumulated in their brains. This article is insinuating that the plaques are brought on by having faulty apo-E lipoproteins--much like the cholesterol plaques on arteries of people with atherosclerosis from high cholesterol.

    There is some confusion, however, because it seems that NMDA receptors are vital to forming memories. So, I don't understand why an NMDA inhibitor would help with azheimer's disease...

    Just trying to clear this up, I found that
    If I recall, Piracetam works mostly on another type of glutamate receptor: the AMPA receptor.
    I guess the verdict is still out on nootropics... One thing is for sure though: THIS SHIT IS CONFUSING AS HELL! ;) My favorites are the directly contradictory tidbits of information!! :)
     
    Last edited by a moderator: Sep 10, 2017
    1. 3/5,
      interesting points
      Apr 13, 2006
  16. psyche

    psyche Palladium Member

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    Umm, isn't alzheimers disease caused by excess of dopamine in frontal lobes?

    Binge-drinking causes memory loss. It's because of the alcohol agonizes the GABA receptors, causing more GABA to be released. Does GABA bind to NMDA receptors and thus cause memory loss...? This doesn't sound like a good hunch. Or is it just because of overall depressing effects on the CNS. On the other hand, I don't remember hearing opiates cause same kind of memory loss. Could you clarify this?
     
  17. sands of time

    sands of time Gold Member

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    No, excess dopamine usually results in schizophrenia. A deficiency of dopamine can result in Parkinson's disease.

    Yes, it is widely believed that alcohol mimics GABA's effect in the brain by having an agonistic effect on the receptor sites. GABA does not bind to NMDA receptor sites though. If NMDA receptor sites are activated for too long, GABA is released as a result. The memory loss you speak of is a result of alcohol mimicing GABA, which is an inhibitory neurotransmitter. This inhibitory effect reduces memory function. Opiates do not effect memory to this degree because opiates do not mimic or increase levels of GABA
     
    1. 3/5,
      great and important distinction between schiz/alzheimers. more people should have this basic info of neurochemistry!
      Apr 14, 2006
  18. Richard_smoker

    Richard_smoker Gold Member

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    Sands,
    I really must apologize for that lengthy post from way back earlier where i tried to 'explain' some shit to you about NT's etc... Sorry. I didn't know that you had so much valuable info in yer membrane! I read her post earlier today, and for the life of me, i couldn't remember what the hell the correct answer was...
    So, HELL YEA!! You're right on the money, senior~! ;) in both aspects.
     
  19. sands of time

    sands of time Gold Member

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    Hey, we all learn somethin every day. By sharing info, your providing many people with a source of info. Keep spillin your brains, someone will learn from it.
     
  20. psyche

    psyche Palladium Member

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    Oh yes I mixed up schizophrenia and Alzheimer. Lack of two enzymes synthesizing and degreding Acetylcholine, Acetyltransferase and and acetylcholinesterase, is also typical to the alzheimers disease. That's because basal forebrain nucleis are heavily dimnished by the disease.

    I seem to have forget to mention that opiates don't target GABA. I just wanted to know if the GABA has furthermore some effect on NMDA, but on afterthougts I don't know what was I getting at by that.
     
    1. 3/5,
      itd be interesting to see if GABA could influence NMDA down the line though.
      Apr 14, 2006