How Do Painkillers Find & Kill Pain?

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iStock

First, we need to make a distinction between the two main classes of painkillers, which are used for different situations and function via different mechanisms.

The first class is the narcotic opioid drugs. These are the heavy-duty drugs, like morphine and codeine, used to treat severe pain. They relieve pain in two ways: first by interfering with and blocking the transmission of pain signals to the brain, and then by working in the brain to alter the sensation of pain. These drugs neither find nor kill pain, but reduce and alter the user's perception of the pain. They're kind of like having an optimistic friend that says, "Hey man, everything will be cool. Nothing's wrong. Here, look at this shiny, distracting thing!"

The other class is the aspirin drugs, like paracetamol and ibuprofen. These are the over the counter drugs we reach for whenever we've got a headache or a sore back. Throughout history, people all over the world were using botanical remedies for pain. The ancient Egyptians used leaves from the myrtle bush, Europeans chewed on hunks of willow bark and Native Americans did the same with birch bark. In the nineteenth century, scientists isolated the chemical in all these plants that gave them their pain relieving properties: salicin (which is metabolized to salicylic acid when consumed). They also discovered that these chemicals produced the side effect of horrendous digestive problems (which answers that other burning question, "Why is that Native American in that old commercial crying?").

Bayer aspirin
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Eventually, a scientist at Bayer Pharmaceutical synthesized a less harmful derivative chemical, acetylsalicylic acid (ASA). Bayer dubbed it Aspirin and commercialized it. Hoffmann went on to develop a "non-addictive" substitute for morphine. The resulting product, heroin, was less successful than aspirin.

Despite its long history, we didn't discover how aspirin works until the early 1970s. Unlike narcotics, aspirin drugs are real workhorses that actually go to the source of pain and stop it. When cells are damaged, they produce large quantities of an enzyme called cyclooxygenase-2. This enzyme, in turn, produces chemicals called prostaglandins, which send pain signals to the brain. They also cause the area that has been damaged to release fluid from the blood to create a cushion so the damaged cells don't take any more of a beating. This cushion is the swelling and inflammation that goes along with our aches and pains. When we take aspirin, it dissolves in our stomachs and travels through the whole body via the bloodstream. Although it's everywhere, it only works its magic at the site of cell damage by binding to the cylooxygenase-2 enzymes and stopping them from prostaglandins. No more prostaglandins means no more pain signals. The cells at the damage site, of course, are still damaged, but we're left blissfully unaware.

This prostaglandin-stopping power is also why people take aspirin regularly to reduce the risk of heart attacks, since prostaglandins in the bloodstream can cause clotting. Additionally, aspirin reduces the production of thromboxane, a chemical that makes platelets, a type of blood cell, sticky. With aspirin in our systems, platelets make less thromboxane and are less likely to form a clot and block an artery.

10 Radiant Facts About Marie Curie

Photo Illustration by Mental Floss. Curie: Hulton Archive, Getty Images. Background: iStock
Photo Illustration by Mental Floss. Curie: Hulton Archive, Getty Images. Background: iStock

Born Maria Salomea Skłodowska in Poland in 1867, Marie Curie grew up to become one of the most noteworthy scientists of all time. Her long list of accolades is proof of her far-reaching influence, but not every stride she made in the fields of chemistry, physics, and medicine was recognized with an award. Here are some facts you might not know about the iconic researcher.

1. Marie Curie's parents were teachers.

Maria Skłodowska was the fifth and youngest child of two Polish educators. Her parents placed a high value on learning and insisted that all their children—including their daughters—receive a quality education at home and at school. Maria received extra science training from her father, and when she graduated from high school at age 15, she was first in her class.

2. Marie Curie had to seek out alternative education for women.

After collecting her high school diploma, Maria had hoped to study at the University of Warsaw with her sister, Bronia. Because the school didn't accept women, the siblings instead enrolled at the Flying University, a Polish college that welcomed female students. It was still illegal for women to receive higher education at the time so the institution was constantly changing locations to avoid detection from authorities. In 1891 Maria moved to Paris to live with her sister, where she enrolled at the Sorbonne to continue her education.

3. Marie Curie is the only person to win Nobel Prizes in two separate sciences.

Marie Curie and her husband, Pierre Curie, in 1902.
Marie Curie and her husband, Pierre Curie, in 1902.
Agence France Presse, Getty Images

In 1903, Marie Curie made history when she won the Nobel Prize in physics with her husband, Pierre, and with physicist Henri Becquerel for their work on radioactivity, making her the first woman to receive the honor. The second Nobel Prize she took home in 1911 was even more historic: With that win in the chemistry category, she became the first person to win the award twice. And she remains the only person to ever receive Nobel Prizes for two different sciences.

4. Marie Curie added two elements to the Periodic Table.

The second Nobel Prize Marie Curie received recognized her discovery and research of two elements: radium and polonium. The former element was named for the Latin word for ray and the latter was a nod to her home country, Poland.

5. Nobel Prize-winning ran in Marie Curie's family.

Marie Curie's daughter Irène Joliot-Curie, and her husband, Frédéric Joliot-Curie, circa 1940.
Marie Curie's daughter Irène Joliot-Curie, and her husband, Frédéric Joliot-Curie, circa 1940.
Central Press, Hulton Archive // Getty Images

When Marie Curie and her husband, Pierre, won their Nobel Prize in 1903, their daughter Irène was only 6 years old. She would grow up to follow in her parents' footsteps by jointly winning the Nobel Prize for chemistry with her husband, Frédéric Joliot-Curie, in 1935. They were recognized for their discovery of "artificial" radioactivity, a breakthrough made possible by Irène's parents years earlier. Marie and Pierre's other son-in-law, Henry Labouisse, who married their younger daughter, Ève Curie, accepted a Nobel Prize for Peace on behalf of UNICEF, of which he was the executive director, in 1965. This brought the family's total up to five.

6. Marie Curie did her most important work in a shed.

The research that won Marie Curie her first Nobel Prize required hours of physical labor. In order to prove they had discovered new elements, she and her husband had to produce numerous examples of them by breaking down ore into its chemical components. Their regular labs weren't big enough to accommodate the process, so they moved their work into an old shed behind the school where Pierre worked. According to Curie, the space was a hothouse in the summer and drafty in the winter, with a glass roof that didn't fully protect them from the rain. After the famed German chemist Wilhelm Ostwald visited the Curies' shed to see the place where radium was discovered, he described it as being "a cross between a stable and a potato shed, and if I had not seen the worktable and items of chemical apparatus, I would have thought that I was been played a practical joke."

7. Marie Curie's notebooks are still radioactive.

Marie Curie's journals
Hulton Archive, Getty Images

When Marie Curie was performing her most important research on radiation in the early 20th century, she had no idea of the effects it would have on her health. It wasn't unusual for her to walk around her lab with bottles of polonium and radium in her pockets. She even described storing the radioactive material out in the open in her autobiography. "One of our joys was to go into our workroom at night; we then perceived on all sides the feebly luminous silhouettes of the bottles of capsules containing our products […] The glowing tubes looked like faint, fairy lights."

It's no surprise then that Marie Curie died of aplastic anemia, likely caused by prolonged exposure to radiation, in 1934. Even her notebooks are still radioactive a century later. Today they're stored in lead-lined boxes, and will likely remain radioactive for another 1500 years.

8. Marie Curie offered to donate her medals to the war effort.

Marie Curie had only been a double-Nobel Laureate for a few years when she considered parting ways with her medals. At the start of World War I, France put out a call for gold to fund the war effort, so Curie offered to have her two medals melted down. When bank officials refused to accept them, she settled for donating her prize money to purchase war bonds.

9. Marie Curie developed a portable X-ray to treat soldiers.

Marie Curie circa 1930
Marie Curie, circa 1930.
Keystone, Getty Images

Marie's desire to help her adopted country fight the new war didn't end there. After making the donation, she developed an interest in x-rays—not a far jump from her previous work with radium—and it didn't take her long to realize that the emerging technology could be used to aid soldiers on the battlefield. Curie convinced the French government to name her Director of the Red Cross Radiology Service and persuaded her wealthy friends to fund her idea for a mobile x-ray machine. She learned to drive and operate the vehicle herself and treated wounded soldiers at the Battle of the Marne, ignoring protests from skeptical military doctors. Her invention was proven effective at saving lives, and ultimately 20 "petite Curies," as the x-ray machines were called, were built for the war.

10. Marie Curie founded centers for medical research.

Following World War I, Marie Curie embarked on a different fundraising mission, this time with the goal of supporting her research centers in Paris and Warsaw. Curie's radium institutes were the site of important work, like the discovery of a new element, francium, by Marguerite Perey, and the development of artificial radioactivity by Irène and Frederic Joliot-Curie. The centers, now known as Institut Curie, are still used as spaces for vital cancer treatment research today.

Why Does Your Arm Hurt After You Get a Flu Shot?

Pornpak Khunatorn/iStock via Getty Images
Pornpak Khunatorn/iStock via Getty Images

If you’ve ever gotten a flu shot, you may have felt soreness in your upper arm for a day or two afterward. That’s just a sign the vaccine is working, immunologists say.

The flu vaccine works by introducing your body to a foreign substance called an antigen (in this case, the antigen is a deactivated or “dead” virus similar to the flu virus). Being exposed to an antigen “primes” immune system cells, preparing them to create antibodies should they ever encounter the foreign substance again [PDF]. The inactive virus in the vaccine can’t make you sick, but it does help sensitize your immune system to potential threats. Essentially, the vaccine puts your body on high alert for anything resembling the flu virus, enabling you to fight off infections and illnesses faster and more effectively than you could otherwise.

In the process of battling the inactive flu virus introduced by the flu vaccine, your immune system also releases mediators like histamine, which causes inflammation. In the event of infection, inflammation is important because it helps your body fight invaders and repair damaged tissue. But it’s also what causes soreness. The flu shot is usually injected into your upper arm, which is why the early immune response—and any pain—tends to be localized there.

Roughly one in five people have this type of painful reaction, immunologist Richard Zimmerman told Popular Science. If you’re susceptible to soreness after receiving a flu shot, there are a few steps you can take to alleviate the pain. Dr. Juanita Mora of the American Lung Association recommends taking an ibuprofen about two hours before getting the shot.

“You can also try icing the injection site to reduce redness and swelling,” Dr. Mora said.

It’s also important to move your arm around after receiving the shot so the vaccine isn’t quite so concentrated in one place. Barring that, you could always try getting the vaccine in your non-dominant arm so that any pain won’t interfere with your everyday activities.

Any pain is worth it, though: Even if you’ve never gotten the flu before, there’s always a chance you could get it in the future. And getting a flu shot also contributes to herd immunity, helping protect higher-risk populations (like children, older adults, and chronically ill individuals) who often can’t receive the flu vaccine for themselves. Keeping up-to-date on vaccines is one of the easiest ways individuals can contribute to community health.

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