Whilst reading about pain perception in the latest version of

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Anonymous
2016-03-27 15:17:27 Post No. 7960643
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Anonymous 2016-03-27 15:17:27 Post No. 7960643 [Report]

Whilst reading about pain perception in the latest version of Kandel's Principles of Neural Science I got really confused. I understand that morphine acts primarily on mu receptors, and more so than enkephalins or dynorphins. However, on page 552, the book states:

"The number of mu receptors on alpha-gamma nociceptors, which mediate fast and acuate pain or "first pain", exceeds that on C fiber nociceptors, which mediate slow persistent or "second pain". This may help to explain why morphine is more effective in the treatment of persistent rather than acute pains."

Should it not be the other way around if morphine has preference for mu receptors and mu receptors are more prevalent on alpha-gamme nociceptors? Is this a typo in the book?

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Anonymous 2016-03-27 15:30:00 Post No.7960657
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Anonymous 2016-03-27 15:30:00 Post No.7960657 [Report]

>>7960643
It says may. If alpha-gamma nocieptors have more mu receptors that would mean that morphine has a weak signal and isn't processed as efficently in the area with more receptors. The area has low levels of mu and the cells compensate by producing more receptors to increase sensitivity.

C fiber nocieptors have less, which in this context would mean it receives a stronger signal of mu and doesn't need as much receptors.

For more clarification google receptor upregulation and downregulation

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Anonymous 2016-03-27 15:39:16 Post No.7960670
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Anonymous 2016-03-27 15:39:16 Post No.7960670 [Report]

It's a typo. Opiates are much more effective on acute pains.

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Anonymous 2016-03-27 15:41:29 Post No.7960679
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Anonymous 2016-03-27 15:41:29 Post No.7960679 [Report]

>>7960657
Thank for your answer, that would explain.

>>7960670
Are you sure about that? There are different kinds of opiates.

Also, I apologise to the critical and keen reader - of course I mean "alpha-delta nociceptors" and not "alpha-gamma nociceptors".

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Anonymous 2016-03-27 17:00:03 Post No.7960811
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Anonymous 2016-03-27 17:00:03 Post No.7960811 [Report]

>>7960679
Yes, opiates are not very good for chronic pain.

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Anonymous 2016-03-27 22:37:04 Post No.7961709
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Anonymous 2016-03-27 22:37:04 Post No.7961709 [Report]

>>7960643

Anon, i'd very much like to talk neurosciene with you. Kandel is my favourite general neuro text.
I've been looking for neuro people to join the /sci/ discord channel for months now.

Here is the invite link. Leave a message there, I check it somewhat regularly

https://discord.gg/0lqbvcXEubLYMdhn

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Anonymous 2016-03-27 22:46:41 Post No.7961728
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Anonymous 2016-03-27 22:46:41 Post No.7961728 [Report]

>>7960643
It seems to me that antagonising the few receptors on C-fibres means less EPSPs in C fibres. More morphine would be needed to antagonise Adelta-fibres. If that makes sense?

I would type more but this keyboard broke.

I'll type more when I get on my other laptop.

I'm >>7961709