Neurons would need energy to generate those pain 'signals'

  • #1
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Hi

A human body is a chemical machine. Every process, such as walking, sleeping, thinking, etc., consumes energy but rate of energy consumption varies from one activity to another. I have been told that when some body part such as forehead, hand, is experiencing, a lot of energy is consumed. This is obvious that neurons would need energy to generate those pain 'signals'. But I'm not sure about that 'a lot energy is consumed'. What do you say on this? Please let me know. Thanks.
 

Answers and Replies

  • #2
bobze
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Hi

A human body is a chemical machine. Every process, such as walking, sleeping, thinking, etc., consumes energy but rate of energy consumption varies from one activity to another. I have been told that when some body part such as forehead, hand, is experiencing, a lot of energy is consumed. This is obvious that neurons would need energy to generate those pain 'signals'. But I'm not sure about that 'a lot energy is consumed'. What do you say on this? Please let me know. Thanks.
Could you clarify the boldfaced?

It depends on what you consider a "lot of energy" that is kind of subjective. Neurons have to constantly use energy shuffling sodium and potassium across their membranes. I suppose compared to other tissues in the body, neural tissue certainly consumes lots of energy.

It is also why neurons are one of the first things to die when you "die". Other tissues can survive "death" for much longer periods because they are "strict" on their requirements to life.
 
  • #3
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I'm extremely sorry. I have missed the key word:
I have been told that when some body part such as forehead, hand, is experiencing PAIN, a lot of energy is consumed.
 
  • #4
bobze
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I'm extremely sorry. I have missed the key word:
I have been told that when some body part such as forehead, hand, is experiencing PAIN, a lot of energy is consumed.
Okay, that makes more sense :smile:.

Well like I said, its really a subjective definition, how much is "a lot".

Certainly when a neuron is transmitting an active message it is using more energy than when it is resting; opening channels, restoring membrane potentials, etc.
 
  • #5
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Thanks a lot, Bobze.

Please remember that I'm not a student of biology or science, in general.

That means it does take energy to generate pain signals. I understand pain signals are there to tell us that there is something wrong with the paining area. But what would really happen if that pain was absent? I think pain killers and anesthetics serve the purpose making the pain less painful.

Once again, thanks. I understand it takes time and energy to help others.
 
  • #6
bobze
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Thanks a lot, Bobze.

Please remember that I'm not a student of biology or science, in general.

That means it does take energy to generate pain signals. I understand pain signals are there to tell us that there is something wrong with the paining area. But what would really happen if that pain was absent? I think pain killers and anesthetics serve the purpose making the pain less painful.

Once again, thanks. I understand it takes time and energy to help others.
Yes, it takes energy to do just about anything in our bodies, because our bodies like to maintain states that are ordered and in disequilibrium.

If we didn't have pain, we don't fare too well. There are rare genetic diseases where people don't have pain and they typically get into all kinds of trouble.

Even with simple things, you sit in the same position to long and feel uncomfortable, thus you change position. People who don't feel pain, don't do simple things like this and it leads to joint and circulation problems.

Or they do something really off the wall and put their hand on a scalding stove--which obviously is problematic.

Pain is an evolved response to let us know "stop doing that" or "hold that part still" etc. Its integral for organisms to survive.
 
  • #7
Borek
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Experiencing pain doesn't use substantially more energy than thinking about that nice chick you have seen in a pub, or solving math problem.
 
  • #8
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Experiencing pain doesn't use substantially more energy than thinking about that nice chick you have seen in a pub, or solving math problem.
Here you're talking about brain consomption. If we look at the whole body, high level of pain can indeed causes higher energy consomption because of its impacts on the autonomous system.
 
  • #9
Borek
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Thinking about the hot chick can make you spend a lot of energy as well, but original question - at least as far as I understand it - was about neurons, not about everything else.
 
  • #10
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This is obvious that neurons would need energy to generate those pain 'signals'.
Actually this is not so obvious. A neuron needs energy to maintain the chemical gradient, not to fire the action potential. Of course the action potential will impact the chemical gradiant, which then need to be restored. So in the end it requieres energy, but that's indirect.
 
  • #11
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Thanks a lot, Bobze. You really cleared it out. Now I understand the good side of pain!

Experiencing pain doesn't use substantially more energy than thinking about that nice chick you have seen in a pub, or solving math problem.
In my opinion it's purely subjective, Borek. Solving a math problem could consume a lot of energy for many like me. Well, that nice chick. The pain of heart is quite different, I believe. And it does consume handsome amount of energy. Thanks for the input.

Here you're talking about brain consomption. If we look at the whole body, high level of pain can indeed causes higher energy consomption because of its impacts on the autonomous system.
Hi Lievo: What's that "autonomous system"? Please let me know.
 
  • #12
Borek
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In my opinion it's purely subjective, Borek. Solving a math problem could consume a lot of energy for many like me. Well, that nice chick. The pain of heart is quite different, I believe. And it does consume handsome amount of energy. Thanks for the input.
You didn't get what I was aiming at. It doesn't matter what kind of signals neurons transmit or what kind of task they do - they always use more or less the same amount of energy. It is just like computer - it doesn't matter whether it looks for Mersenne primes or checks spelling of a document, amount of energy is the same.

That's not exactly true, as some tasks may need more resources to be solved, but that's the general idea - energy depends on resources used, not on kind of task. Two tasks requiring same resources require same amount of energy.

Hi Lievo: What's that "autonomous system"? Please let me know.
http://en.wikipedia.org/wiki/Autonomic_nervous_system
 
  • #13
bobze
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You didn't get what I was aiming at. It doesn't matter what kind of signals neurons transmit or what kind of task they do - they always use more or less the same amount of energy. It is just like computer - it doesn't matter whether it looks for Mersenne primes or checks spelling of a document, amount of energy is the same.

That's not exactly true, as some tasks may need more resources to be solved, but that's the general idea - energy depends on resources used, not on kind of task. Two tasks requiring same resources require same amount of energy.



http://en.wikipedia.org/wiki/Autonomic_nervous_system

I agree Borek, with what you've said. But, I think the question if directed specifically at those sensory fibers which get activated from a "resting" state--Then they would use more energy (for restoring chemical disequilibrium etc) than during the "resting" state.

Its a rather hard question to address from a layman standpoint in my opinion because different nerve fibers transmit different sensory information. Certainly, as you pointed out the CNS is very active. I took the OP to be referring to the PNS though since he was talking about "transmitting pain" back to the brain.

Suppose then for example, we had some free nerve endings in your finger which monitor heat. You grab a scalding hot pain, many of these fibers which were "not active" will now transmit their message back to the CNS saying "Ow hot". In transmitting the message, since most is saltatory conduction it is "relatively" cheap to transmit. However, the nerve must then expend energy reestablishing its electrochemical gradients etc. Likewise, it would need to take back up neurotransmitters (or make new ones depending on the type of nerve) at the synapse.

Like I pointed out though, how much energy is "a lot"? Its rather subjective. If you placed your whole hand on the stove and activated a lot of sensory fibers saying "Ow" then certainly there's a much greater energy cost than not doing this--in regards to transmitting lots of sensory messages. But that is probably a good energy investment for your body to make :tongue2:
 
  • #14
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original question - at least as far as I understand it - was about neurons, not about everything else.
You're likely right. However, I don't know any technics to record the total energy consumption of a body part such as the brain -not to mention the neurons. So I guess the information Jackson was told about concerns the body as a whole.

Hi Lievo: What's that "autonomous system"? Please let me know.
Bad name for the autonomic nervous system as Borek mentionned. It controls the para- versus sympathetic systems, and among other functions it is both sensitive to pain and has a lot to do with optimal uses of energy.
 
  • #15
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When a person is experiencing pain, it may not be the person's energy that is being used to send the electrical signals to the brain. The energy that is causing the signal to be generated is coming not from the person's body but from the harmful elements of the environment. For example, when a person is blinded by bright light, deafened by loud sound, singed by heat, or stabbed by a knife, the energy that causes the pain is coming from the light, sound, heat and mechanical energy of the external sources and the nerves merely act as electrical generators that will convert this energy into electrical energy to be sent to the brain. The reason why the person uses energy when they are in pain is because the cells that are damaged by harmful forces use energy to regenerate tissue.
 
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@bobze

Just one thing: your points assume that pain is the same thing as nociception. It's not the same. In fact, the most painfull conditions have usually nothing or very little to do with the nociceptive information arising from the peripheral nerves.

EDIT: @Bararontok too :wink:
 
  • #17
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The energy used to transmit signals depends on the type of pain or problem the person is experiencing. If the pain is caused entirely by the energy of an external source, then the nerves may not need to draw on the person's energy to transmit the signal. But alternatively, the brain uses energy to record the information coming from the signal because it stores information by reconnecting neurons in a different arrangement, it also uses energy to warn the cells in the damaged area to begin regeneration and causes the muscles of the person to contort and tighten to elevate anxiety levels, release adrenaline to raise aggresion, as well as triggering involuntary motor actions that would cause the person to move away from the source of danger. All of this uses energy, so it would be right to say that it is only in the preliminary transmission of information that the body's energy is not used.
 
  • #18
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then the nerves may not need to draw on the person's energy to transmit the signal
Sorry, but no this does not work this way. Action potentials are dynamically regenerated along the axon. There is no such things as the external energy going through the nerves.
 
  • #19
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Yes, because the connections of the neural networks are not permanent like electrical wires and need to be constantly regenerated to ensure a stable connection otherwise the signal will be lost especially since the human body is constantly moving and there is the possibility that nerves will be cut. Because the cells have to increase the electrochemical gradient by releasing sodium ions in order to increase the conductivity of the neural connection and permit more electrical current to flow. Ultimately, energy is required to switch on certain neural connections to deliver specific signals to the brain which will depend on the input stimuli. And even after the damaging stimuli is gone, the nerves still send pain signals to the brain so long as the tissue is physically damaged so this requires that part of the body to generate its own electricity to maintain the transmission of electrical impulses which also uses energy. The energy of the stimuli may be what generates the initial electrical impulse but the other processes that ensure that information is constantly fed to the brain draws energy from the body itself.
 
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  • #20
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there is the possibility that nerves will be cut.
Don't worry too much about that :redface:
 
  • #21
Experiencing pain doesn't use substantially more energy than thinking about that nice chick you have seen in a pub, or solving math problem.
Uh.. Borek.. Can we all please try to make this site more child friendly by not posting testosterone fueled thoughts.

Yes, because the connections of the neural networks are not permanent like electrical wires and need to be constantly regenerated to ensure a stable connection otherwise the signal will be lost especially since the human body is constantly moving and there is the possibility that nerves will be cut.
Nerves don't just get cut while people are moving. They are built into your body system and well protected.

Because the cells have to increase the electrochemical gradient by releasing sodium ions in order to increase the conductivity of the neural connection and permit more electrical current to flow.
Sodium ions are not there for increasing conductivity. These are not your chemical electrolyte solutions where we have passage of electric current between battery ends. They are their to increase or decrease membrane potential.

The energy of the stimuli may be what generates the initial electrical impulse but the other processes that ensure that information is constantly fed to the brain draws energy from the body itself.
Energy from the stimuli (as far as I know) cannot and is not used for any impulse generation.
 
  • #22
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Some estimates of cellular energy balance have suggested that in an secretory epithelial cell up to 50% of the cellular ATP consumed is due to Na K ATPase activity. I can only imagine that this figure is equal or greater in a neurone. Thats a lot of energy! So energizing the membrane is a costly business. I should point out though that this process happens irrespective of whether we use the neurone to transmit, i.e. the membrane potential has to be set up anyway - we dont just set it up when we need to transmit. So although there is more energy consumed in an active neurone it may be a small increase over a large resting cost. Remember a tiny amount of ions flow to generate an AP - its not like Na floods the cell and K floods out and we need to reverse that - bulk concentrations hardly move since the required flux to change rmp is tiny!!
 
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  • #24
Borek
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Does it mean receptor takes energy from stimuli and later neurons use this energy to transfer the signal?
 
  • #25
Pythagorean
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It's a matter of physics for physical receptors. For a stimuli to have an effect on a mechanoreceptor or photoreceptor, some energy exchange has to occur between the stimuli and the receptor. As far as I know, it's always from stimuli to receptor (a photoreceptor absorbing light or work being done on a mechanoreceptor).

Not sure how chemoreceptors work in this respect.
 

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