A discussion on Pain

Rockdoc Franz wrote: Reading this has me wondering if the polar opposite of prolonged exposure to capsaicin is once again a shut-down function to protect the body in some way?? That is rather interesting. Peppers are a distasteful experience for me, so I've no experience with what you describe. It is most interesting indeed. Why would the body switch sensations? Interesting question.

Very likely - physically, continued stimulation of the nerve will cause a depletion of calcium ions which will impair the neuron's ability to generate an action potential and signal the brain. Why is it important that the neuron be "desensitized" or shut down? Continued stimulation would probably lead to apoptosis - programmed cell death - which would result in losing that nerve and ability to respond to capsaicin, forever. Back when we were foraging for food, and learning what would kill us and what wouldn't, these kinds of taste receptors could mean the difference between life and death.

But capsaicin (and TRPV1) has broader effects in the body too. When you have a very potent molecule, it's important to have good brakes on its effects:
http://en.wikipedia.org/wiki/TRPV1

In humans, drugs acting at TRPV1 receptors could be used to treat neuropathic pain associated with multiple sclerosis, chemotherapy, or amputation, as well as pain associated with the inflammatory response of damaged tissue, such as in osteoarthritis.[10]
The major roadblock for the usefulness of these drugs is their effect on body temperature (hyperthermia). The role of TRPV1 in the regulation of body temperature has emerged in last few years. Based on a number of TRPV-selective antagonists' causing an increase in body temperature (hyperthermia), it was proposed that TRPV1 is tonically active in vivo and regulates body temperature[11] by telling the body to "cool itself down". Without these signals, the body overheats.

(Rather interesting, too, is the paragraph on TRPV1 in the central nervous system and its role in depression).

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

Capsaicin is being explored as a possible prophylaxis for Type 1 diabetes by researchers in Toronto, Canada.

The American Association for Cancer Research reports studies suggesting capsaicin is able to kill prostate cancer cells by causing them to undergo apoptosis.[37][38] There have been several clinical studies conducted in Japan and China that showed natural capsaicin directly inhibits the growth of leukemic cells.[39] Another study carried out at the University of Nottingham suggests capsaicin is able to trigger apoptosis in human lung cancer cells as well.[40]

Capsaicin is also the key ingredient in the experimental drug Adlea, which is in Phase 2 trials as a long-acting analgesic to treat post-surgical and osteoarthritis pain for weeks to months after a single injection to the site of pain.[41] More over, it reduces pain resulted rheumatoid arthritis[42] as well as joint or muscle pain from fibromyalgia or other causes.

Capsaicin may help treat ear infections such as otitis.[43] There is some evidence that capsaicin may help treat heartburn and circulatory problems such as heart disease from atherosclerosis or plaque that block the arteries to the heart. Capsaicin may also help in reducing risks of arrhythmia. Capsaicin is also a great natural expectorant and can be used to clear the lungs of mucus.

In 2006, it was discovered that tarantula venom activates the same pathway of pain as is activated by capsaicin, the first demonstrated case of such a shared pathway in both plant and animal anti-mammal defense.[23]

TPP wrote: Thank You! I try.

And we all know that men die before women...

So Pain, wife & dead are all 4 letter words... See there is a connection....

So is love, food, mate (no gender implied), and drug!

Words so subtly influence our thought processes and physical feelings.

http://www.ncbi.nlm.nih.gov/pubmed/21375099
The effects of positive or negative words when assessing postoperative pain.
Chooi CS, Nerlekar R, Raju A, Cyna AM.
Anaesth Intensive Care. 2011 Jan;39(1):101-6.

Department of Women's Anaesthesia, Women's and Children's Hospital, Adelaide, South Australia, Australia.

Negative or harsh words such as 'pain' and 'sting' used to describe sensations prior to potentially painful procedures have been shown to increase pain. We aimed to determine whether the reporting of pain and its severity is affected by the way it is assessed during anaesthesia follow-up after caesarean section. Following caesarean section, 232 women were randomised prior to post-anaesthesia review. Group N participants were asked questions containing the negative word 'pain, "Do you have any pain?" and then asked to rate it on a 0 to 10 point Verbal Numerical Rating Scale. Group P participants were asked questions using more positive words, "How are you feeling?" and "Are you comfortable?".

The assessment of pain after caesarean section, using more positive words, decreases its incidence but does not affect its severity when measured by pain scores. Words that focus the patient on pain during its assessment may lead some to interpret sensations as pain which they might not do otherwise. These findings may have important implications when assessing and researching postoperative pain.

This is pretty cool stuff - past conventional wisdom has held that pain perception and sensitivity is mostly a function of the brain, but that's not the case. Peripheral nerves throughout the body and the spine itself plays significant roles in our perception of pain. The comment that really caught my eye in the article was this:

Unlike the text of a book or the bytes of a hard disk, the information stored in our brain is constantly on the verge of being erased.

The protein that they discuss below is involved in strengthening neurons' "memories", but like everything, not enough, or too much of it, can be adverse to our health or quality of life.

http://topicfire.com/share/A-memory-for ... 27503.html
A memory for pain, stored in the spine
by Ed Yong
May 11th, 2011

You slam your hand in a door, and the experience becomes etched into your brain. Your body remembers it too. For days afterwards, the neurons in your spine carry pain signals more easily from your hand to your brain. As a result, your hand feels more sensitive, and even the lightest touch will trigger an unpleasant reaction. It’s as if your spine carries a memory for pain.

This is more than a metaphor. Two groups of scientists have found that one special molecule underlies both processes. It helps to store memories in our brains, and it sensitises neurons in our spines after a painful experience. It’s a protein called PKMzeta. It’s the engine of memory. http://topicfire.com/share/A-memory-for ... 27503.html

Reference: Asiedu, Tillu, Melemedjian, Shy, Sanoja, Bodell, Ghosh, Porreca & Price. 2011. Spinal Protein Kinase M zeta Underlies the Maintenance Mechanism of Persistent Nociceptive Sensitization. J Neurosci http://www.jneurosci.org/content/31/18/6646