Theories of Pain
In the past several decades, important discoveries about pain-suppressing chemicals came about because scientists were curious about how morphine and other opium-derived painkillers, or analgesics, work. For some time neuroscientists had known that chemicals were important in conducting nerve signals (small bursts of electric current) from cell to cell. In order for the signal from one cell to reach the next in line, the first cell secretes a chemical, called a "neurotransmitter," from the tip of a long fiber that extends from the cell body. The transmitter molecules cross the gap separating the two cells and attach to special receptor sites on the neighboring cell surface. Some neurotransmitters excite the second cell -- allowing it to generate an electrical signal. Others inhibit the second cell -- preventing it from generating a signal.
When investigators injected morphine into experimental animals, they found that the morphine molecules fit snugly into receptors on certain brain and spinal cord neurons. Why, the scientists wondered, should the human brain -- the product of millions of years of evolution -- come equipped with receptors for a man-made drug? Perhaps there were naturally occurring brain chemicals that behaved exactly like morphine.
Numerous studies around the world led to the discovery of not just one pain-suppressing chemical in the brain, but a whole family of such proteins. The smaller members of the family were named enkephalins (meaning "in the head"). In time, the larger proteins were isolated and called endorphins, meaning the "morphine within." The term endorphins is now often used to describe the group as a whole.
The discovery of the endorphins lent weight to an overarching theory of pain: endorphins released from brain nerve cells might inhibit spinal cord pain cells through pathways descending from the brain to the spinal cord. Laboratory experiments subsequently confirmed that painful stimulation led to the release of endorphins from nerve cells. Some of these chemicals then turned up in cerebrospinal fluid, the liquid that circulates in the spinal cord and brain. Laced with endorphins, the fluid could bring a soothing balm to quiet nerve cells.
A New Look at Pain Treatments
Further evidence that endorphins figure importantly in pain control came from studies of some of the oldest and newest pain treatments. These studies involved the use of a drug called naloxone that prevents endorphins and morphine from working. Injections of naloxone resulted in a return of pain which had been relieved by morphine and certain other treatments. But, interestingly, some pain treatments are not affected by naloxone: their success in controlling pain apparently does not depend on endorphins. Thus nature has provided us with more than one means of achieving pain relief.
* Acupuncture
* Local electrical stimulation
* Brain stimulation
* Placebo effects
* Acupuncture. Probably no therapy for pain has stirred more controversy in recent years than acupuncture, the 2,000-year-old Chinese technique of inserting fine needles under the skin at selected points in the body. The needles are manipulated by the practitioner to produce pain relief which some individuals report lasts for hours, or even days. Does acupuncture really work? Opinion is divided. Many specialists agree that patients report benefit when the needles are placed near the site of the pain, not at the body points indicated on traditional Chinese acupuncture charts. The case for acupuncture has been made by investigators who argue that local needling of the skin excites endorphin systems of pain control. Wiring the needles to stimulate nerve endings electrically (electroacupuncture) also activates endorphin systems, they believe. Further, some experiments have shown that there are higher levels of endorphins in cerebrospinal fluid following acupuncture.
Those same investigators note that naloxone injections can block pain relief produced by acupuncture. Others have not been able to repeat those findings. Skeptics also cite long-term studies of chronic pain patients that showed no lasting benefit from acupuncture treatments. Current opinion is that more controlled trials are needed to define which pain conditions might be helped by acupuncture and which patients are most likely to benefit.
* Local electrical stimulation. Applying brief pulses of electricity to nerve endings under the skin, a procedure called transcutaneous electrical nerve stimulation (TENS), yields excellent pain relief in some chronic pain patients. The stimulation works best when applied to the skin near where the pain is felt and where other sensibilities like touch or pressure have not been damaged. Both the frequency and voltage of the electrical stimulation are important in obtaining pain relief.
* Brain stimulation. Another electrical method for controlling pain, especially the widespread and severe pain of advanced cancer, is through surgically implanted electrodes in the brain. The patient determines when and how much stimulation is needed by operating an external transmitter that beams electronic signals to a receiver under the skin that is connected to the electrodes. Stimulation-produced analgesia is a costly procedure that involves the risk of brain surgery. However, patients who have used this technique report that their pain "seems to melt away." The pain relief is also remarkably specific: the other senses remain intact, and there is no mental confusion or cloudiness as with opiate drugs.
* Placebo effects. For years doctors have known that a harmless sugar pill or an injection of salt water can make many patients feel better -- even after major surgery. The placebo effect, as it is called, has been thought to be due to suggestion, distraction, the patient's optimism that something is being done, or the desire to please the doctor (placebo means "I will please" in Latin).
Later experiments suggested that the placebo effect may be neurochemical, and that people who respond to a placebo for pain relief -- a remarkably consistent 35 percent in any experiment using placebos -- are able to tap into their brains' endorphin systems. To evaluate it, investigators designed an ingenious experiment. They asked adults scheduled for wisdom teeth removal to volunteer in a pain experiment. Following surgery, some patients were given morphine, some naloxone, and some a placebo. As expected, about a third of those given the placebo reported pain relief. The investigators then gave these people naloxone. All reported a return of pain.
How people who benefit from placebos gain access to pain control systems in the brain is not known. Scientists cannot even predict whether someone who responds to a placebo in one situation will respond in another. Some investigators suspect that stress may be a factor. Patients who are very anxious or under stress are more likely to react to a placebo for pain than those who are more calm, cool, and collected. But dental surgery itself may be sufficiently stressful to trigger the release of endorphins -- with or without the effects of placebo. For that reason, many specialists believe further studies are indicated to analyze the placebo effect.
As research continues to reveal the role of endorphins in the brain, neuroscientists have been able to draw more detailed brain maps of the areas and pathways important in pain perception and control and have found other members of the endorphin family. At the same time, clinical investigators have tested chronic pain patients and found that they often have lower-than-normal levels of endorphins in their spinal fluid. If we could just boost their stores with man-made endorphins, perhaps the problems of chronic pain patients could be solved.
Not so easy. Some endorphins are quickly broken down after release from nerve cells. Other endorphins are longer lasting, but there are problems in manufacturing the compounds in quantity and getting them into the right places in the brain or spinal cord. In a few promising studies, clinical investigators have injected an endorphin called beta-endorphin under the membranes surrounding the spinal cord. Patients reported excellent pain relief lasting for many hours. Morphine compounds injected in the same area are similarly effective in producing long-lasting pain relief.
But spinal cord injections or other techniques designed to raise the level of endorphins circulating in the brain require surgery and hospitalization. And even if less drastic means of getting endorphins into the nervous system could be found, they are probably not the ideal answer to chronic pain. Endorphins are also involved in other nervous system activities such as controlling blood flow. Increasing the amount of endorphins might have undesirable effects on these other body activities. Endorphins also appear to share with morphine a potential for addiction or tolerance.
Meanwhile, chemists are synthesizing new analgesics and discovering painkilling virtues in drugs not normally prescribed for pain. Much of the drug research is aimed at developing nonnarcotic painkillers. The motivation for the research is not only to avoid introducing potentially addictive drugs on the market, but is based on the observation that narcotic drugs are simply not effective in treating a variety of chronic pain conditions. Developments in nondrug treatments are also progressing, ranging from new surgical techniques to therapies like exercise and biofeedback.
New and Old Drugs for Pain
When you complain of headache or low back pain and the doctor says take two aspirins every 4 hours and stay in bed, you may think your pain is being dismissed lightly. Not at all. Aspirin, one of the most universally used medications is an excellent painkiller. Scientists still cannot explain all the ways aspirin works, but they do know that it interferes with pain signals where they usually originate, at the nerve endings outside the brain and spinal cord: peripheral nerves. Aspirin also inhibits the production of chemicals called prostaglandins that are manufactured in the blood to promote blood clotting and wound healing. Unfortunately, prostaglandins, released from cells at the site of injury, are pain-causing substances. They actually sensitize nerve endings, making them -- and you -- feel more pain. Along with increasing the blood supply to the area, these chemicals contribute to inflammation -- the pain, heat, redness, and swelling of tissue damage.
Some investigators now think that the continued release of pain-causing substances in chronic pain conditions may lead to long-term nervous system changes in some patients, making them hypersensitive to pain. People suffering such hyperalgesia can cry out in pain at the gentlest touch, or even when a soft breeze blows over the affected area. In addition to the prostaglandins, blister fluid and certain insect and snake venoms also contain pain-causing substances. Presumably these chemicals alert you to the need for care -- a fine reaction in an emergency, but not in chronic pain.
There are several prescription drugs that usually can provide stronger pain relief than aspirin. These include the opiate-related compounds codeine, propoxyphene, morphine, and meperidine. All these drugs have some potential for abuse, and may have unpleasant and even harmful side effects. In combination with other medications or alcohol, some can be dangerous. Used wisely, however, they are important recruits in the chemical fight against pain.
In the search for effective analgesics, physicians have discovered pain-relieving benefits from drugs not normally prescribed for pain. Certain antidepressants are used to treat several particularly severe pain conditions, notably the riveting pain of facial neuralgias like trigeminal neuralgia and the excruciating pain that can follow an attack of shingles.
Interestingly, pain patients who benefit from antidepressants report pain relief before any uplift in mood. Pain specialists think that the antidepressant works because it increases the supply of a naturally produced neurotransmitter, serotonin. (Doctors have long associated decreased amounts of serotonin with severe depression.) But now scientists have evidence that cells using serotonin are also an integral part of a pain-controlling pathway that starts with endorphin-rich nerve cells high up in the brain and ends with inhibition of pain-conducting nerve cells lower in the brain or spinal cord.
Antiepileptic drugs have also been used successfully in treating trigeminal neuralgia. The rationale for the use of antiepileptic drugs (principally carbamazepine) is based on the theory that a healthy nervous system depends on a proper balance of incoming and outgoing nerve signals. Trigeminal neuralgia and other facial pains or neuralgias are thought to result from damage to facial nerves. That means that the normal flow of messages to and from the brain is disturbed. The nervous system may react by becoming hypersensitive: it may create its own powerful discharge of nerve signals, as though screaming to the outside world "Why aren't you contacting me?" Antiepileptic drugs -- used to quiet the excessive brain discharges associated with epileptic seizures -- quiet the distress signals and in that way may relieve pain.
Nondrug Treatments
Treatment for pain can include counseling, relaxation training, meditation, hypnosis, biofeedback, or behavior modification. The philosophy common to all of these approaches is the belief that patients can do something on their own to manage their pain. That something may mean changing attitudes, feelings, or behaviors associated with pain.
* Psychotherapy
* Relaxation and meditation therapies
* Biofeedback
* Behavior modification
* Psychotherapy. Some patients may benefit from individual or group counseling. Trained professionals can help the chronic pain sufferer learn valuable coping skills. They also provide the patient with much needed support -- both psychological and emotional -- for dealing with pain.
* Relaxation and meditation therapies. These methods enable people to relax tense muscles, reduce anxiety, and alter mental states. Both physical and mental tension can make pain worse, and in conditions such as headache or back pain, tension may be at the root of the problem. Meditation, which aims at producing a state of relaxed but alert awareness, is sometimes combined with therapies that encourage people to think of pain as something remote and apart from them. The methods promote a sense of detachment so that the patient thinks of the pain as confined to a particular body part over which he or she has control. The approach may be particularly helpful when pain is associated with fear, as in cancer.
* Biofeedback. Some individuals can learn voluntary control over certain body activities if they are provided with information about how the system is working -- how fast their heart is beating, how tense their head or neck muscles are, how cold their hands are. The information is usually supplied through visual or auditory cues that code the body activity in some obvious way -- a louder sound meaning an increase in muscle tension, for example. How people use this biofeedback to learn control is not understood, but some practitioners of the art report that imagery helps: they may think of a warm tropical beach, for example, when they want to raise the temperature of their hands. Biofeedback may be a logical approach in pain conditions that involve tense muscles, like tension headache or low back pain. But results are mixed.
* Behavior modification.This psychological technique (sometimes called operant conditioning) is aimed at changing habits, behaviors, and attitudes that can develop in chronic pain patients. Some patients become dependent, anxious, and homebound -- if not bedridden. Chronic pain may be a welcome friend, relieving them of the boredom of a dull job or the burden of family responsibilities. These psychological rewards -- sometimes combined with financial gains from compensation payments or insurance -- work against improvements in the patient's condition, and can encourage increased drug dependency, repeated surgery, and multiple doctor and clinic visits. There is no question that the patient feels pain. The hope of behaviour modification is that pain relief can be obtained from a program aimed at changing the individual's lifestyle. The program begins with a complete assessment of the painful condition and a thorough explanation of how the program works. It is essential to enlist the full cooperation of both the patient and family members. The treatment is aimed at reducing pain medication and increasing mobility and independence through a graduated program of exercise, diet, and other activities. The patient is rewarded for positive efforts with praise and attention. Rewards are withheld when the patient retreats into negative attitudes or demanding and dependent behaviour.
by Cesar Galvez
Endorphins create a natural high to restore perspective and calm during episodes of stress and anxiety.
I was tired, but I had multitude of errands run-take wife to the market, shuttle the kids to a study group, and then complete a major assignment for graduate school. Lack of sleep only added to my anxiety.
Things went from bad to worse driving home. There was a sudden movement in front of me. I hit the brakes, but not quickly enough. I spent the next three hours conversing with the police and insurance company-precious time I could have devoted to my assignment. By the time I sat at my desk to review my articles, I had only four hours to do the work I was in big trouble. My problems had multiplied, looming like titans.
Despite the shortness of time, I left my desk and went to the gym, ran on the track, exercised in the machine room, took a shower and got dressed. I felt calm. My problems were still there, but they were no longer the giants I had thought they were. Upon returning home, I completed my assignment and met the deadline.
What helped me? Substances produced in the brain called endorphins.
The Importance of Endorphins
Endorphins are substances produced only by the human brain. They are important for pain control, as well as regulating blood pressure and body temperature (Andersson and Lundeberg, 1995). During stress, people who secrete endorphins have lower heart rate reactivity. Before and during recovery from stress, an endorphin producer has lower mean arterial blood pressure (McCubbin, et al., 1992). Endorphins are the body's own opiate (Terenius, 1982).
Endorphins are hundreds of times more powerful than heroin and many times more than morphine (Cornejo, 1995; Davis, 1984). In terms of stimulant power, they have a tremendous impact on attitude, the will and mental insight. Experimental work with animals has shown improvements in memory and learning capacity when endorphins were involved (Davis, 1984).
Great leaders produce high levels of endorphins (Cornejo, 1995). From a physiological viewpoint, this helps explain their energy, tenacity and power despite the problems they face. For instance, how did a person like Mother Teresa, so small and frail, work so hard and feed thousands of people each day?
Endorphins make us feel good. They give us a sensation of wellness and peace, helping shrink our problems to their true dimensions. They diminish our giants, creating a euphoric effect that gives us energy, enthusiasm and power to accomplish daily tasks (Pierce, et al., 1993).
Since endorphins are so important, what can we do to produce them? Several stimuli make our brains produce these substances, such as meditation, laughing and positive attitude (Harte, Eifert and Smith, 1995). There is one stimulus, however, that makes our brains produce endorphins in larger amounts-intensive aerobic exercise (Rahkila, et al, 1988).
Conditions of Aerobic Exercise:
Aerobic exercise includes vigorous walking, jogging, hiking, biking and step exercising. A few important conditions transform common exercise into aerobic exercise:
* Frequency--Aerobic exercise should be performed at least three or four times a week. Once a week helps, but it is insufficient. From a heart disease prevention viewpoint, some research suggests exercising aerobically once a week is worse than doing nothing.
* Duration--Each exercise session should last at least 35 minutes. During the first seven minutes of exercise you consume circulant glucose. You consume stored glucose up to the first 30 minutes. If exercise continues, the body synthesizes glucose from its stored fat. This entire process occurs only in the presence of a large amount of oxygen.
* Sweat--Aerobic exercise should produce a profuse amount of sweat. This indicates endorphin secretion.
When you satisfy these prerequisites, you will feel relaxed-especially after taking a bath or shower. The problems of life will appear less ominous. This does not mean they will disappear, but your attitude will improve significantly. Initially, your problems may appear in monstrous proportions, but endorphins help you see them in their true dimensions, providing you with enough energy, strength and enthusiasm to keep going in your daily work tasks. Take advantage of this natural chemical process.