Whoever is spared personal pain must feel himself called to help in diminishing the pain of others.
We must all carry our share of the misery which lies upon the world.

- Albert Schweitzer
 

Pain adds rest unto pleasure, and teaches the luxury of health.

- Martin Fraquhar Tupper
 

Examples of the unity of life?

Washington - Aspirin helps ease the aches and pains suffered by plants much in the way it helps people and animals, researchers say.  They said their findings shed more light on the "pain" mechanism that plants have, which is similar to that of animals.

Researchers in the past have found that plants do register injury, and can release chemical signals to alert their neighbours.  An example is the acacia tree, which responds to browsing by animals by sending chemical signals into the air.  Neighbouring trees respond by producing a chemical in their leaves that tastes nasty.

Writing in the Journal of Biological Chemistry, the international team found that aspirin, a broad-acting painkiller, can block this signal in plants.  Ralph Backhaus and Zhiqiang Pan of Arizona State University and colleagues at the US Department of Agriculture and the Institut de Biologie Moleculaire des Plantes in Strasbourg, France, worked together on the study.

Aspirin interferes with production of prostaglandin which, in animals, is produced in response to injury, causing swelling and pain.  In plants it blocks production of jasmonic acid, the researchers found.  "Jasmonic acid is a hormone that is made when plants are in distress.  It signals the production of plant-defence compounds.  It works a little like a shot of pain, warning the plant that it is under attack," Backhaus said in a statement.  "It can also volatise and warn nearby plants, a chain reaction that's like a warning signal to other plants.  This seems to particularly apply to insect attack, as the alerted plants then produce specific compounds that produce insect gastro-intestinal distress."

The researchers did not propose a practical use for their finding.

Source: Reuters Online Wednesday 5 August 1999

One Man's Pain May Be Another Woman's Agony

by Nigel Hawkes

Women not only feel pain slightly more than men but almost certainly do so in a distinctly different way.

The discovery, by a team at the University of Illinois, raises the possibility of "his and hers" painkillers, formulated to work for the different brain chemistry of the two sexes.

Jeffrey Mogil says that it has been known for some time that women have a slightly lower pain threshold then men - though the difference, he says, is not great.

More surprising is the evidence - found so far only in mice and rats - that pain perception in men and women is qualitatively as well as quantitatively different.  "Both feel pain but they are responding differently, by activating different circuitry in the brain," Professor Mogil says.

The main difference he has found is in a set of receptors in the brain called the NM13A receptors - for n-methyl d-aspartate.  These are involved in the reception of pain signals in male mice, because if they are blocked by using a compound called MK801, male mice become insensitive to painkillers.  But female mice do not.

This indicates that the females are not using the same pathway, but must have a different one, so far unidentified.  The finding also applies to rats and probably to human beings as well.  But explaining why the sexes should have evolved different pain perception systems is not easy.

"Here's one speculation," Professor Mogil says.  "We did a lot of our evolving as hunter-gatherers.  There was a separation of tasks in hunter-gathering societies: men hunted, women gathered.  One might imagine there might be more adaptive pressure on males to evolve a strategy to kill the pain of trauma - lion bites and spear points.  Females might have been less exposed to those types of pain, and more exposed to other types of pain: visceral pain involved in childbirth, for example.  So there might have been subtly different selective pressures, such that the best analgesic mechanism in men would have different properties than the best in women."

The argument also applies to rodents, in a modified form.  Males are more likely to fight among themselves, so evolving a means of bearing the pain would be more important to them than to females.

Professor Mogil's work with inbred strains of mice has shown huge differences in their response to pain.  Some strains can barely tolerate any degree of it, while others do not seem to mind at all.  He says that this probably applies equally to humans, and should make us pause before mocking those who whine about pain.  "There really are differences in our response to pain."

The great differences also raise hopes that if the genes that control them can be identified, much more effective painkillers could be developed. - The Times

Source: The Dominion 8 March 2000

Brain Links Pain with Pleasure

New treatments for pain could be developed

Scientists have found that areas of the brain that respond to feelings of pleasure also react to the sensation of pain.  The findings could lead to a better understanding of the effects of pain within the brain and to new ways to diagnose and treat pain.

The new research carried out by the USA's Massachusetts General Hospital (MGH) backs up previous studies.  The MGH's Dr David Borsook said: "Pain is a complex experience that includes both a sensation and an emotional reaction.  Understanding this emotional component would be key to developing new approaches to helping chronic pain in patients, who are at increased risk for anxiety, depression and suicide."

Researchers used a technique called functional magnetic resonance imaging (fMRI) to take pictures of the brains of eight study volunteers.  The eight young men had a thermode or small heat pad attached to their hands, which administered warm or hot temperatures for brief periods, alternating with normal skin temperatures.  Brain images focused both on areas previously identified as being involved with the sensory experience of pain and on those found in earlier studies to be activated by response to such stimuli as cocaine, food and money.

The results showed the painful "hot" temperatures caused activation not only of the classic pain circuitry in the brain, but also some of the areas previously described as reward circuitry.  The reward circuits responded more quickly than the pain circuits during the administration of hot temperatures.  The pain circuits were active towards the end of the heat administration period.

Lino Becerra, one of the authors of the study, said: "These are two systems that were never associated in the past and it's the first time we have seen something aversive activating these reward structures."

Co-author Dr Hans Breiter said: "It would appear the philosophers Spinoza and Bentham, who proposed that pleasure and pain were part of the same spectrum, were right."

The scientists go on to suggest this response is due to circuits in the brain that handle reward trying to analyse stimuli and judge which are important to survival.  It is hoped these conclusions could pave the way for developing objective tests to measure pain and pain relief and the creation of pain-relieving drugs that target the structures previously associated with reward.  This strategy could lead to the treatment of pain that does not respond to traditional medications.

British pain imaging expert Dr Irene Tracey from Oxford University believes such findings could bring hope of developing alternative pain remedies, which do not involve drugs.  She said: "This research provides information which is critical for future studies that will pave the way for pain sufferers being given alternative therapies to combat their suffering."

Source: news.bbc.co.uk Friday 7 December 2001

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