How Pain Works

Pain (noun) physical or mental suffering or distress, especially an unpleasant sensation arising from injury or disease. 

Since we all pretty much hate pain, why do we feel it What good can come from it The truth is that pain is very, very helpful to us. Humans as a species would likely not have survived very long without the sensation of pain. Pain tells us when something is injuring or damaging our skin, muscle, and other tissues and organs. 

WHEN WE DON T FEEL PAIN AT MOMENTS WE EXPECT IT THE MOST 

Pain can act in strange ways. Many people suffer traumatic injuries but later state that, at the time, they felt no pain at all. For example, on March 30, 1981, John Hinckley, Jr., attempted to assassinate President Ronald Reagan with a handgun. When the gunshots were fired, President Reagan s aides pushed him into his limousine to protect him and then sped off. No one, not even President Reagan, knew immediately that he had been shot in the chest with a 9-mm bullet. 

A few moments later, President Reagan slumped against the car door and felt blood pouring from his chest. Only then did he start to feel excruciating pain. Up until that point, he had felt no pain at all -1 

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I o find new and more effective medicines, chemists use various models that J. describe how drugs work. By far, one of the most useful models of drug action is the lock-and-key model. The basis of this model is the connection between a drugs chemical structure and its biological effect. For example, morphine and all related pain-relieving opioids, such as codeine and heroin, have the T-shaped structure shown in Figure 14.1. 

The enzyme that catalyses these remarkable reactions, cyclooxygenase, is an important target for medicinal chemists. Inhibiting PG synthesis can bring about a reduction of inflammation and pain, in fact, this is how aspirin works, it was not, of course, designed to work that way and its mode of action was discovered decades after its use began. There is a price to pay for such a useful... 

It is only in recent years that researchers have found out exactly how it works in our bodies. Previously all they knew was that it worked for a wide range of ailments, thinning the blood, lowering blood pressure and relieving pain for arthritis sufferers. 

As a side note, remember that the most frequently used drug, aspirin, was discovered by Native Americans who brewed the bark of the willow tree to treat aches and pains. Of course, they didn t realize that the brown tea they shared with early settlers contained what scientists came to identify as acetylsalicylic acid, more commonly known as aspirin. It was only within recent decades that medical researchers have determined just how aspirin works its anti-inflammatory and painkilling wonders by altering hormonelike substances called prostaglandins. 

How it works Produces analgesic anti-inflammatory effect by inhibiting prostaglandin synthesis, reducing inflammatory response and intensity of pain stimulus reaching sensory nerve endings. 

How it works Binds with opioid receptors within CNS, altering processes affecting pain perception, emotional response to pain. Decreases intestinal motility by local and central actions. 

The discovery of the biological role of nitric oxide has shed light on how nitroglycerin works as a drug. For many years, nitroglycerin tablets have been prescribed for cardiac patients to relieve the pain caused by brief intermptions in the flow of blood to the heart, although how it worked was not understood. We now know that nitroglycerin produces nitric oxide in the body, which causes muscles to relax and allows the arteries to dilate. 

ECT is a fast and effective treatment, typically used in severe depression, catatonia or mania. It s sometimes used in moderate depression where there s been a good prior response, and some argue for a role in treatii clozapine-resistant schizophrenia. Eariy ECT was horrific and traumatic, and although it s veiy different now, mai people still think it involves pain, screaming, smoke and sparks. Like mai of the drugs used in psychiatry, we don t know exactly how it works. Your consultant is ultimately responsible for the decision to give ECT. 

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