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Physiology

The chemistry of acupuncture

Needles activate neurotransmitter and protect against gastric ulcer and halts in breathing during sleep

Recognized as a medical specialty in Brazil ten years ago, acupuncture still lacks proof that it is effective from the scientific point of view. Studies with animals and human beings indicate that this age-old Chinese technique, based on the application of needles at specific points of the body to reestablish health, does indeed work, but only in certain cases. The use of the needles has already proved to be efficient in fighting pain and the intense nauseas caused by the use of medicaments against cancer. It has also revealed itself as a powerful ally in the treatment of asthma, of cerebral vascular accident and the abusive use of drugs.

Now, three studies conducted at the Federal University of São Paulo (Unifesp) are showing that acupuncture may help to combat gastritis and ulcers, besides the interruptions in breathing that impair the quality of sleep. More importantly, these researches are helping people to understand how it works. All the indications are that the needles, applied to certain points of the body, bring about the release or the better use of a chemical substance called serotonin. Better known as a chemical messenger (neurotransmitter) that takes information from one cell to another in the central nervous system, serotonin also acts as a powerful analgesic in the peripheral nerves, which extend through the arms, legs and trunk.

According to the oriental tradition, the vital energy Qi circulates through the organism through meridians that end at specific points of the skin. The good functioning of the body depends on the equilibrium between two opposite and complementary forces – yin and yang – that make up Qi.  If this balance is lost, the body falls sick. Acupuncture then tries to reestablish this energy balance by the manipulation of needles stuck into some of the more than a thousand points now identified.

In the interpretation of western medicine, these points correspond to nerve endings that, when excited by means of needles or by heat, send a signal to the central nervous system, which, in turn, deciphers it and sends back a response to specific regions of the body. “We do not yet know how this process begins, nor whether the serotonin is produced in greater quantities or mere made better use of by the neurons”, comments neurophysiologist Luiz Eugenio Mello, one of the coordinators of the studies at Unifesp. “The results show that acupuncture needs serotonin to work”, he says.

This is not a recent suspicion. In the 1980s, studies carried out in Japan and in China indicated that it was this neurotransmitter that was responsible for the reduction in pain after the sessions of acupuncture. Interested in producing scientific grounding for acupuncture, the researchers from Unifesp decided to see whether serotonin was also associated with the benefic effects observed in the treatment of other problems. The first studies indicate that no serotonin, no way.

In one of the experiments, the group from São Paulo evaluated whether acupuncture could alleviate the symptoms of sufferers from sleep apnea, as the frequent interruptions of up to ten seconds in breathing during nighttime rest are called. These blockages in the passage of air – usually caused by the narrowing of the pharynx, a muscular tube that takes air to the lungs – may occur up to 30 times an hour in the serious cases. As the person wakes up at each episode, sleep ceases to be restorative. On the next day, they are more tired than when they went to bed. Despite being effective, treatment is uncomfortable. Doctors indicate the use by their patients of a device known as a CPAP – standing for Continuous Positive Airway Pressure –, a mask connected to a small compressor that maintains constant the flow of air to the lungs.

The team coordinated by specialists from three areas – Luiz Eugenio Mello, from neurophysiology, Sergio Tufik, from sleep medicine, and Ysao Yamamura, from the Chinese Medicine and Acupuncture Sector – then decided to see whether ten applications of acupuncture in the course of three months would produce any real benefit for these people. The researchers selected 36 sufferers from apnea and separated them into three groups. The members of the first group were not treated, while the people in the second were given applications of needles at points that are recognized as not producing any effect (false points) – in this case, the objective was to see whether the simple suggestion that acupuncture may work produces any effect on the organism. Only the components of the third group were given an application of needles at the correct points.

After three months, the researchers reassessed the participants. The interruptions in breathing worsened amongst those who were not given any treatment. Those who underwent the sessions of false acupuncture reported, in a general way, that their sleep had improved, but an examination that measures the electrical activity of the brain during sleep did not confirm these results. Mello’s team only found a real improvement amongst those treated with applications of needles at the correct points: half ceased to show any interruptions in their breathing, while there was an 80% reduction in the episodes of the other half. “From the quantitative point of view, the improvement brought by acupuncture was similar to that achieved with the CPAP”, explains Anaflávia Freire, one of the authors of the study. “But acupuncture was infinitely superior in terms of quality of life”, the researcher adds; she attributes the result to the action of the serotonin, associated with the strengthening of the muscles of the trachea.

In another experiment, the group from Unifesp compared, in rats, the effects of acupuncture in combating gastric ulcers, using another technique of oriental medicine, called moxibustion. Moxibustion – or moxa, as it is also known – uses a red-hot stick of leaves of the Artemisia vulgaris plant, rolled up in the shape of a cigar, to heat the energy points of acupuncture, or the needles themselves applied at these points. According to Chinese medicine, moxibustion acts on the nerve fibers that conduct stimuli in a slower manner, while the needles act on fast-conducting fibers. The data indicates that both techniques help in combating gastric ulcers.

Before the applications of acupuncture or of moxibustion, the researchers gave the animals a dose of indomethacin, an anti-inflammatory that induces the formation of lesions in the stomach. Half an hour later, some rats were submitted to the treatment with moxa, applied for five minutes on the points recommended by acupuncture – on the side of the paws, to combat the problem in the stomach. A second group was given applications at false points, while a third was not treated. Six hours after the sessions of moxibustion, the researchers observed significant improvements in the animals from the first group. The number of lesions in the stomach was four times lower than the number shown by the rats that were not given any treatment and were part of the control group. In the rats that were given applications at fictitious points, the number of lesions was half the number shown by the control group, according to an article published in Digestive Diseases and Sciences.

Perhaps the skeptics may question whether these results may not be due merely to the effects of the heat, recognized to be anti-inflammatory. To dispel the doubts, the team compared the action of the moxa with the action of two other sources of heat: a red-hot cigar and a hot water bottle. Once again, the results brought confirmation: the oriental technique was twice as efficient as cigars and three times more than a hot water bottle. But it remained to understand why moxa reduces the appearance of lesions, when used at the correct temperature (60°C).

The answer came up in a third work, carried out by Gisele Sugai. She found that, in rats, moxa speeds up the movements of the stomach that push the food to the intestines. The increase in the rhythm of these movements expels the indometacin more rapidly and prevents lesions, as the team described in an article published in the October 2004 issue of Physiology Behaviour. In this same study, Gisele observed that the application of needles in the paws of the animals produced as effect similar to moxa. “In this situation, it is probable that serotonin helps to speed up the movements of the stomach”, says Mello.

The next step was to see whether the reduction in the lesions of the stomach really was associated with the serotonin. The rats were then given a dose of parachlorophenylalanine (PCPA), which blocks the production of this neurotransmitter. This time, the effect of the needles on the movement of the stomach was nil. The PCPA also significantly reduced the stimulation caused by the moxa. “When there is production of serotonin, the results of acupuncture are significantly better”, Mello explains. As the study was carried out with rats, it is hardly probable that the reduction in the lesions was derived from the placebo effect – a real result produced by the belief that an innocuous substance or treatment is going to work.

Understanding the analgesic effect sparked off by the needles has increased recently, with a study published in Neuroimage. Using a technique that makes images of the brain in activity, George Lewith, from Southampton University, found that, when applied correctly, the needles activate areas that produce analgesic substances, the endorphins, besides areas associated with the inhibition of pain. But consensus on the effectiveness of this oriental technique seems far away. Klaus Lind, from the Technical University of Munich, Germany, compared the effects of real acupuncture and those from acupuncture with false needles, against migraine. Published in May in the Journal of the American Medical Association, the results suggest that acupuncture exerts only a psychological influence on the organism.

In the search for scientific evidence about the effectiveness of acupuncture, the patients are the winners. In 1992, Ysao Yamamura created, at Unifesp the Chinese Medicine and Acupuncture Sector, which, besides carrying out research, attends to cases of acute bone and muscular pains. Three years later, physiatrician Wu Tu Hsing organized the course of specialization in acupuncture of the Orthopedics and Traumatology Institute of the Faculty of Medicine at the University of São Paulo (USP).  In the institute’s outpatient department, about a hundred patients a week with pains in the bones and joints are attended to. “Prejudice is decreasing”, explains Hong Jin Pai, from the Pain Center of USP’s Neurology Clinic. The efforts of these pioneers were worth it. In 1995, the Federal Medical Council recognized acupuncture as a specialty of medicine. It is calculated today that there are 50 courses for specialization in acupuncture in medical schools in the country, a scenario very different from the one a few decades ago, when the technique was applied by people without any training in the health area.

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