Martina schreef op donderdag 19 mei 2016, 14:47:


Filmpjuuuhhhh!

Een stukje uit 'Why Zebras Don't Get Ulcers' van Robert Sapolsky: (http://more-minerals.blogspot.nl/2014/11/robert-sapolsky-placebos-and-pain.html )

"Acupuncture stimulates the release of large quantities of endogenous opioids, for reasons no one really understands.
The best demonstration of this is what is called a subtraction experiment: block the activity of endogenous opioids by using a drug that blocks the opiate receptor (most commonly a drug called naloxone). When such a receptor is blocked, acupuncture no longer effectively dulls the perception of pain.

Endogenous opioids turn out to be relevant to explaining placebos as well. A placebo effect occurs when a person's health improves, or the person's assessment of their health improves, merely because they believe that a medical procedure has been carried out on them, regardless of whether it actually has. This is where patients in a study either get the new medicine being tested or, without knowing it, merely a sugar pill, and sugar pill folks get somewhat better.
(...)

This makes a great deal of sense, given what we have now seen about pain processing in the brain. As an example of such a placebo effect, IV infusion of painkillers is more effective if the patient sees the infusion occurring than if it is done on the sly—knowing that a pain-reducing procedure is being carried out adds to its effectiveness. I saw a great example of this a few years back when my then two-year-old daughter came down with an ear infection. She was miserable beyond consolation, clearly in tons of pain. Off to the pediatrician and, amid much wailing and protestations of pain, she had her ears examined. Yup, she's got a huge infection, both ears, said the doc, disappearing to get an injection of antibiotics. We turn to find our daughter looking serene. "My ears feel much better now that the doctor fixed them," she announced. Placeboed by having some instrument stuck in her ears.

Not surprisingly, it turns out that they work by releasing endogenous opioids. As but one example of the evidence for that, block opiate receptors with naloxone, and placebos no longer work."