The development of drugs and other treatments for specific symptoms or conditions relies heavily on either serendipity (the chance finding of a beneficial effect) or on an understanding of underlying mechanisms. In pain, for example, there are limited ways in which we can block pain signals – such as activating opiate receptors or inhibiting prostaglandins. There are only so many ways in which you can interact with these systems. The discovery of a novel mechanism of modulating pain is therefore most welcome, and has the potential of leading to entirely new treatments that may have better side-effect profiles than existing treatments and also have additive clinical effects.
A recent study by Nana Goldman et. al., published in Nature Neuroscience, adds to our understanding of pain relief by identifying the role of adenosine in reducing pain activity in the peripheral nervous system. The researchers, in a nice series of experiments, demonstrated that producing a local painful stimulus in mice causes the local release of ATP (adenosine triphosphate) that peaks at about 30 minutes. This correlates with a decreased pain response in the mice. Further, if drugs are given that prolong the effect of adenosine, the analgesic effect itself is prolonged.
Also, if drugs are given that activate the adenosine A1 receptor, the observed analgesic effect is replicated. When these experiments are replicated in knockout mice that do not have the gene for the adenosine A1 receptor, there is no observed analgesic effect.
Together these experiments are fairly solid evidence that local pain results in the local release of adenosine that in turn binds to the adenosine A1 receptor inhibiting the pain response. This is potentially very exciting – it should lead to further investigation of the adenosine A1 receptor and the effects of activating and inhibiting it. This may lead to the development of drugs or other interventions that activate these receptors and may ultimately be a very useful addition to our ability to treat acute and chronic pain.
A correspondent wrote:
I hear all day long on my local radio station commercials for The Water Cure, which was created by a Dr. Batmangelli (I have no idea how to spell his name) promising wonderful cures by eliminating caffeine and alcohol and drinking water and sprinkling sea salt on your food. If you REALLY want to get cured even faster, swim in the ocean everyday.
That’s Dr. Fereydoon Batmanghelidj. His Big Idea was that dehydration is the main cause of disease. It was untenable to begin with, is supported by no evidence, was debunked on Quackwatch several years ago, and Dr. Batmanghelidj died in 2004, so I was surprised to hear it was still being vigorously promoted. But not very surprised. After all, homeopathy is still around.
The Water Cure is another in a long list of alleged miracle cures discovered by “lone geniuses” who are allegedly persecuted by a resistant medical establishment. These stories follow a pattern, and I think it is worthwhile looking at this prime example to understand something of the psychology of self-deception that is involved. (more…)
Before ethical standards changed, doctors used to occasionally fool patients with placebo injections of sterile saline or water. If my obstetrician had tried to give me sterile water instead of an epidural, I probably would have hit him. But apparently women are getting sterile water injections for childbirth and are telling us they work. What’s going on?
A recent study in Sweden compared sterile water injections to acupuncture for relief of labor pain. It found that sterile water produced significantly greater pain relief and relaxation. It concluded, “Women given sterile water injection experience less labor pain compared to women given acupuncture.”
I’m puzzled, because the study also says “there were no significant differences regarding requirements for additional pain relief after treatment between the 2 groups.” 85% and 90% got nitrous oxide, 40% and 47% got epidurals, and other conventional interventions were also used. It seems to me the conclusion could just as well have been “Women given sterile water injections report less labor pain than women given acupuncture, but require just as much additional pain relief.” (more…)