Let’s say I’m feeling calm and a sudden, short noise startles me and results in norepinephrine being released into the synaptic cleft. Provided I realize it’s safe and don’t freak myself out further, how long will it take for norepinephrine neurochemicals to go through their cycle and get back into the reuptake pump?
I’m taking norepinephrine here but if you have data or even a guesstimate on any neurotransmitter, that could provide useful information.
I know not a lot about neurochemistry, but I’m sitting next to someone who does. If no one comes by who can help more, it sounds like you’ll want to look into “clearance rate”. The mechanisms can include not just reuptake, but also diffusion and binding to other receptors.
Poking around briefly, it seems . . . complicated
From some of the figures, it looks like we’re talking ~100 ns to a couple ms
I would have expected electrical signals to fade within that timeframe but not chemical signals. It’s counterintuitive to think that, say, norepinephrine-based alertness and threat response could disappear in a couple ms. It doesn’t seem like we would have evolved that way. Maybe I’m not asking the question correctly or there’s some communication problem in terms of terminology.
If I perceive a reward which results in increased synaptic dopamine release then lose any prospect of that reward and focus on something else, it’s possible for the neurochemical signals involved to fade in microseconds?
I find that if I am agitated enough, it takes at least 20-30 minutes for the feeling to fade. For instance, when my mother had a medical crisis, and they initially misread a number that wasn’t blood oxygen as the blood oxygen number, and that number meant she was probably brain-dead, or very damaged. Whoever read the number corrected it within seconds. But the emotional impact of that statement lingered for quite a while. It was weird to KNOW that the cause of the emotion was fake, and still feel the emotion.
My minimally-informed guess is that if your adrenal glands dump NE, you have some serum level that is doing stuff for a longer time than just cleft NE would otherwise be around.
Ugh that was not quite English. Neurotransmitters seem to get cleared quickly from the synaptic cleft, but may not exclusively be released there.
I’ve found that even when I meditate as well as I can, it takes me 10 minutes to wind down. In suboptimal conditions, I can see how it would take 20-30 minutes. Meditation techniques often advise having 20 minute sessions.
I’ve also read that heart rate and blood pressure take about 10 minutes to come back to baseline after exercise.
When a part of the brain, like the amygdala, increases in activity, more blood flows to it, correct? Any idea how long that takes to wind down?
So, the 10-30 minutes would be based on hormones rather than neurotransmitters? I would have expected hormones to have longer cycles than that but I guess that’s the point of asking.
How long does it take for insulin to respond to changes in blood sugar?
Good questions, but I think now we’ve exited the realm where I can fake help and will have to hope someone else can pop in.
Wiki says 10 minutes: Insulin - Wikipedia
“Beta cells in the islets of Langerhans release insulin in two phases. The first-phase release is rapidly triggered in response to increased blood glucose levels, and lasts about 10 minutes. The second phase is a sustained, slow release of newly formed vesicles triggered independently of sugar, peaking in 2 to 3 hours.”
So, it looks like the quick response mechanisms through which the body (aside from the brain) affects the mind takes at least 10 minutes to wind down which then lets the mind switch gears.
I don’t know if there’s any relation to attention span which usually lasts 10-15 minutes. It’s unlikely that would be affected by the rest of the body though.
How long do child tantrums tend to last? How about panic attacks?
I’m no expert, but I do read a lot about this stuff because I enjoy it, some thoughts:
You mentioned neurotransmitters in the OP, but there are lots of different ones and some act differently and have different lifespans. In general, you don’t want the signal traveling from one neuron to another neuron to last because it would override/confuse future signals.
Some chemicals like hormones last longer and can act like neurotransmitters also, so they seem to be serving a different longer spanned function.
I’m mainly concerned with stress response but information about any other is welcome.
Can you go on about this override/confuse mechanism?
Neurons are firing rapidly and encoding information into the signal in many different ways, for some it’s encoded in the firing rate. If the neurotransmitters last longer than one cycle, then the receiving neuron is receiving less information. It’s tougher to determine the rate and it may not know the other neuron stopped firing.
Pulse frequency modulation?
I’m not sure if that’s analogous to multipath propagation or if it’s like a radar sending Pulse_A then Pulse_B, getting a return but not being sure if the return is from Pulse_A or Pulse_B. I don’t remember what that second problem is called.
I don’t believe it’s been mentioned yet, but the half-life of epinephrine is 2 minutes. After 10 minutes (5 half-lifes), then, it’s basically gone.
So, assuming your brain has been reassured and stops sending commands to release epinephrine, you should be back to normal in minutes.
Thanks for the datum. I didn’t think to look it up and it fits very neatly with the rest of the info in the thread considering that (IIRC) the “5 half-lives and it’s gone” rule of thumb is commonly used in medicine.
I might have added by means of a counterexample regarding the ‘stress response’, that cortisol has a much longer biological effect. Once it’s been released (stimulated in part by catecholamines), it circulates with a half-life of 66 minutes. And, that does not take into account the hours of delay for the effect to even begin in cells into which cortisol has entered, where it affects transcription and thence protein synthesis.
You have different types of neurotransmitters, and different functions of the same molecules depending on whether they are released into the synaptic cleft, or into the blood stream. In the synapse, they open ligand gated ion channels and elicit an action potential in the partner cell forming the synapse, and are usually cleared within milliseconds, enabling the connection to transmit the next signal (Determining the Neurotransmitter Concentration Profile at Active Synapses - PMC). Acting on other type of receptors,e.g GPCRs, they can have a neuromodulatory function, modulating the sensitivity of a nerve cell to an incoming signal e.g by regulating the responsiveness of voltage-gated Calcium channels that are needed to release neurotransmitter in response to an incoming signal.
Released into the blood stream, the lifetime of such molecules depends largely of whether it is water soluble, and therefore cleared at its first pass through the kidney, or whether it binds to a serum carrier protein (or albumin). When you get to biologial effects, things can get much more complicated, as the target cells can, for example, release more of the same signal or other signals, triggering a whole cascade of complex responses.
Thanks you for the great information.
Is adrenaline water soluble? How long does it take for the kidneys to filter an amount of blood equivalent to that contained in the body?
n/m