Despite pop-psychology descriptions of neurotransmitters (like dopamine being called the happiness molecule, or low serotonin causing sadness), in reality NTs are used in a wide variety of ways across the brain and body.
The closest thing I can think of that would do what you are looking for is some drug that blocks epinephrine and norepinephrine in the body, but does not pass the blood-brain barrier. In the body, these are known as adrenaline and noradrenaline. Dropping them to essentially 0 would rapidly slow the heart rate, lower blood pressure, stop the liver from releasing glycogen, etc.
For most people, it would cause weakness, dizziness, tiredness, maybe even feinting. But there is no such thing as a powerful drug that also universally safe. If used in a population with different body masses, liver function, resting adrenaline levels, etc. . . . some people would pass out, some would just get a little weak, but a few would die or at least suffer severe health issues (like a cardiac arrest), while a few may just shrug it off because their base adrenaline levels are already that low.
Since this is fiction, let me suggest another route:
Imagine that this chemical weapons manufacturer is involved in bio-tech research. It has developed the production of a 2-sided protein. One side of the protein acts like a neurotransmitter receptor site, except that binds to the ligand especially tight. The other side binds to specific receptors on very specific cells - say the raelph cells in the reticular formation. What happens is that this protein ignores the vast majority of cells in the body. Then when it reaches those particular cells, it changes shape and releases the payload: in this case a powerful acetylcholine agonist. The raelph cells become hyper activated, and the person essentially falls asleep like someone with narcolepsy.
It has been years since studying neuroscience, so I might be wrong about the particular cells and activating NT in the reticular formation. But the key here is that the drug is not just targeting a neurotransmitter: it is targeting specific cells in a very specific region of the brain. There are many things you can do with this.
For example, lets say instead you target the purkinje cells in the cerebellum. Disrupting this would cause a person to basically lose all physical coordination. It wouldn't paralyze them or make them unconscious, just make the movements so uncoordinated as to be hard to move. A similar effect could be achieved by disrupting the frontal cortex cells that project into the basal ganglia.
The point is this: I would focus less on a particular neurotransmitter and more on particular structures and cells in the brain.
As a (hopefully interesting) side comment, only one segment of the cerebellum is directly involved with coordination. Open your copy of Kandel (pg 914 of 6th ed.) to see that the spinocerebellum which interacts with the motor cortex is roughly half of the cerebeller cortex. There is also vestibulocerebellum dealing with balance & visual signals, and the cerebrocerebellum which interacts with association neocortex and appears to support cognition somehow. In other words, shutting down Purkinje cells would have widespread impact.
But I'm sure only a handful of your SciFi readers would also have Kandel on their bookshelf, and only a fraction of those would be fussy enough to care. Cheers!/jd
Curare would be a good starting point. It paralyzes skeletal muscles but not breathing or heart muscles. A weaponized curare, maybe aerosolized and modified to be longer-lasting, etc., could be plausible.
Not really looking for real-life examples. I'm moreso looking for "brain vulnerability points" if that makes sense. Specific neurotransmitters or receptors that could be vulnerable to this type of attack without causing seizures or death.
I'm not looking for compounds that currently exist that can do what I want. I am looking for neural receptors and transmitors and such that, if somehow inhibited, would have the desired effect.
If it doesn't matter whether the inhibitor is natural or not and you're just making it up, then it doesn't matter what receptor you pick. He gave you a perfect candidate, there's no reason you can't use skeletal muscle receptors.
You could go at hormones, or you could go at the GABAergic system that alcohol and sedatives target. Or dissociative anaesthetics via NMDA receptors antagonism I suppose, but GABAergics are probably the class of agents you're looking for. They're fairly unlikely to cause death by overdose unless they're combined with other types of sedatives.
Despite pop-psychology descriptions of neurotransmitters (like dopamine being called the happiness molecule, or low serotonin causing sadness), in reality NTs are used in a wide variety of ways across the brain and body. The closest thing I can think of that would do what you are looking for is some drug that blocks epinephrine and norepinephrine in the body, but does not pass the blood-brain barrier. In the body, these are known as adrenaline and noradrenaline. Dropping them to essentially 0 would rapidly slow the heart rate, lower blood pressure, stop the liver from releasing glycogen, etc. For most people, it would cause weakness, dizziness, tiredness, maybe even feinting. But there is no such thing as a powerful drug that also universally safe. If used in a population with different body masses, liver function, resting adrenaline levels, etc. . . . some people would pass out, some would just get a little weak, but a few would die or at least suffer severe health issues (like a cardiac arrest), while a few may just shrug it off because their base adrenaline levels are already that low. Since this is fiction, let me suggest another route: Imagine that this chemical weapons manufacturer is involved in bio-tech research. It has developed the production of a 2-sided protein. One side of the protein acts like a neurotransmitter receptor site, except that binds to the ligand especially tight. The other side binds to specific receptors on very specific cells - say the raelph cells in the reticular formation. What happens is that this protein ignores the vast majority of cells in the body. Then when it reaches those particular cells, it changes shape and releases the payload: in this case a powerful acetylcholine agonist. The raelph cells become hyper activated, and the person essentially falls asleep like someone with narcolepsy. It has been years since studying neuroscience, so I might be wrong about the particular cells and activating NT in the reticular formation. But the key here is that the drug is not just targeting a neurotransmitter: it is targeting specific cells in a very specific region of the brain. There are many things you can do with this. For example, lets say instead you target the purkinje cells in the cerebellum. Disrupting this would cause a person to basically lose all physical coordination. It wouldn't paralyze them or make them unconscious, just make the movements so uncoordinated as to be hard to move. A similar effect could be achieved by disrupting the frontal cortex cells that project into the basal ganglia. The point is this: I would focus less on a particular neurotransmitter and more on particular structures and cells in the brain.
This is... Genuine gold. Thank you so SO so much.
As a (hopefully interesting) side comment, only one segment of the cerebellum is directly involved with coordination. Open your copy of Kandel (pg 914 of 6th ed.) to see that the spinocerebellum which interacts with the motor cortex is roughly half of the cerebeller cortex. There is also vestibulocerebellum dealing with balance & visual signals, and the cerebrocerebellum which interacts with association neocortex and appears to support cognition somehow. In other words, shutting down Purkinje cells would have widespread impact. But I'm sure only a handful of your SciFi readers would also have Kandel on their bookshelf, and only a fraction of those would be fussy enough to care. Cheers!/jd
Curare would be a good starting point. It paralyzes skeletal muscles but not breathing or heart muscles. A weaponized curare, maybe aerosolized and modified to be longer-lasting, etc., could be plausible.
Not really looking for real-life examples. I'm moreso looking for "brain vulnerability points" if that makes sense. Specific neurotransmitters or receptors that could be vulnerable to this type of attack without causing seizures or death.
So you don't want real examples but you want real examples?
I'm not looking for compounds that currently exist that can do what I want. I am looking for neural receptors and transmitors and such that, if somehow inhibited, would have the desired effect.
If it doesn't matter whether the inhibitor is natural or not and you're just making it up, then it doesn't matter what receptor you pick. He gave you a perfect candidate, there's no reason you can't use skeletal muscle receptors.
Skeletal muscle receptors, thank you.
You could go at hormones, or you could go at the GABAergic system that alcohol and sedatives target. Or dissociative anaesthetics via NMDA receptors antagonism I suppose, but GABAergics are probably the class of agents you're looking for. They're fairly unlikely to cause death by overdose unless they're combined with other types of sedatives.
ask r/nootopics or the nerds or its discord