This is a pretty good explanation of nociception:

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

And this on dopamine. Dopamine is a pretty complex subject and involves
alot of chemistry.

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

Every patient reaches a point in pain perception, that is unique to them, where intolerability occurs.
The concept of chronic pain is very hot right now in professional circles.
Many continuing education requirements for relicensure in most states for medical professionals, require at least one course in chronic pain management now.

Acute nociceptive pain that is not treated properly is thought to be a trigger for chronic pain. However, using opiates for certain forms of pain prematurely, can increase the number of pain receptors centrally and lead to a vicious circle for the patient. I attended a chronic pain seminar last spring, and this factor was discussed at length. In the area of chronic headache, use of opiates actually CAUSES more headache. The tertiary clinic that sponsored this lecture along with the Univ. of Michigan takes all patients OFF narcotics when they enter their program. They have found that use of narcotic meds twice a week can induce chronic headache. I believe the continued research into the central pain pathways that become abberant in chronic headache, will lead to better management of neuropathic pain.

Some of neuropathic pain is nociceptive. That is it can be blocked in the periphery with Lidocaine, menthol, for example. Shingles pain is the classic presentation, of nerves that become damaged in some way by the herpes zoster virus and keep firing when they are not supposed to.

And some of neuropathic pain is central. So that the medications for this problem involve both methods of pain control.

And as we all know, this is not an easy subject and varies from person to person.

I personally wish that the research finds ways to heal us. Not just block the central problems. Medicine always seems to go toward the short fix first.
When the long fix is discovered, PN then may approach a "cure".

I wish that I could take painkillers my PN pain is permanently between 9-10 nothing and I mean nothing eases it.I spend most of my days and nights on the computer looking for some sort of relief or reading up on whatever I can find on PN, looking for something anything to help with this bleeding crap of a symptom/disease whatever you wish to call it.Now if one of you can help me with my pain please tell me how in layman's terms ? not everybody went to college......Liz.

Are you talking about narcotics?

If so, then you should consider a Fibromyalgia diagnosis also.
This disorder ramps up pain perception up to many times normal for
these patients. Typically narcotic pain relievers do not work for these patients,
because endogenous endorphins are very high and sitting on the receptors.

Other methods of pain control are then used:
This thread explains some of it:
http://neurotalk.psychcentral.com/thread20030.html

With fibromyalgia there is often a trigger in the body that sets off the
pain cycle. It can be arthritis, PN, a car accident or trauma, even a vaccine.
A person can have multiple diagnoses.

At the beginning of my PN.I was able to take painkillers after a yr or so it all changed.At first my GP.thought I was overdosing (I would go to bed fine and would wake up in hospital) during the night I would throw up,and when my husband tried to wake me up he couldn,t,sometimes I would be out of it for days.It went on like that for a while my Dr got Brian (DH) to keep an eye on my meds,but every now and again it would happen,no warning whatsoever I would go to bed fine and wake up in the hospital days later (I always threw up while sleeping)My GP tried different painkillers to see if was them it didn,t make a difference,then back in 2005 it happened again only this time I inhaled vomit into my lungs and ended up with pneumonia.This time it was a helicopter ride to the nearest city (I live in a small mining town) and when I came to my PN.had taken over my entire body from head to toes,over the next 3 mths I regained some feeling back from waist up not 100% but better than nothing.My Dr and myself cant say it was the painkillers too many ??? but I did try taking painkillers again about 2yrs ago and my husband noticed changes coming over me so I stopped taking them,every now and then I talk my Dr into trying again because of my pain.So we tried again about 9mths ago and the same thing happened,but it didn,t get to coma stage,A whole heap of other stuff happened also but i'd be here till doomsday writing it down,but you get my meaning on painkillers ?... Liz...xxx

Painkillers is a wide net. What kind of medications caused this?

My next thought is, have you been tested for acute intermittent porphyria?

~~ All opiods (< or opiates) not sure what you call them,but you get the drift.As for being tested for Acute Intermittent Porphyria I have never heard of it,so my answer would have to be no......Liz.

Hi. I can relate about meds. I am not at the same point I was last year pain wise thank goodness. At one time last year I cried through vicodin every few hours. I have tried contless meds with little success actually better off them all together. This is why my docs have encouraged a scs or catheter, Right now for me that is to big but have you looked into something like that if it is right for you. I was also told cause some of my syptoms though have pn alo lead to fivro which meds don't help for.Mrd D at the Cleveland Clinic too they take all patients of those meds too and you have to learn to retrain your brain.That with those meds your brain becomes extra sensitive to pain. Maybe I am off. I was a little out of it in pain during the lecture.
Hang in there I do know the trapping fear of nothing helping the pain. I hope you do find what works for you