The discovery of the brain’s source of pain can lead to a new generation of painkillers

Research led by Fan Wang, a neurobiology professor at Duke’s School of Medicine and founding director of the Wang Lab, invented a special optogenetic technique that can turn on and off brain regions. With the help of this technique, Wang and her team got to the bottom of pain’s mystery: specific neurons in the central amygdala.

A history of pain

Pain is one of the two pillars of life, along with pleasure. The two extremes between which we live our lives day by day. Although unwanted, our life depends on pain. Pain is our guardian. It keeps us away from dangerous stimuli, it tells us when something is wrong with our body and mind, and it is an important factor in making decisions.

Pain helps us know ourselves. We don’t find pleasure in the same things. Pain is also a source of satisfaction. When we want something that it isn’t easy to get, and we fight for it, we suffer for it, we accept the challenge of pain. And when we go through pain to achieve what we want, the satisfaction of being stronger than the pain takes its place.

Pain mystery

The science behind pain has always been a mystery. The first attempts to knock it off date back in the antiquity. The pain locker was discovered in 1984, when the first general anesthesia (GA) was performed in Boston, at Harvard’s Massachusetts General Hospital.

This became the crucial battle mankind won against its inherent vice of being mortal. It took science 20 years until the first surgery was performed under GA, in 1904, by Japanese doctor Hanaoka Seishū.

But scientists never quite understood how does GA arrests pain. They’ve mapped the brain to understand how pain works. But so much of the brain is mingled in the process that it became impossible to untangle the mechanism and find the turn on/off button. Until now.

“Pain is a complicated brain response. It involves sensory discrimination, emotion, and autonomic (involuntary nervous system) responses. Treating pain by dampening all of these brain processes in many areas is very difficult to achieve,” said Wang.

Finally defeated by science

Wang’s research was conducted on lab mice. Mice have played a key role in medicine and have helped mankind since 1976. We owe mice quite a lot!

Until now, studies were centered on understanding the regions of the brain that are turned on by pain. And they are so many, that is pretty hard to turn them all off. This is why pain killers don’t always work. Wang decided to work from a different perspective.

The mice were submitted to pain stimuli while the researchers mapped the multitude of brain regions that were activated. They discovered that 16 of those regions activated in the pain process were linked to the central amygdala.

The amygdala

Amygdala is a double region that is duplicated on both sides of the brain.  Memory, decision-making, and emotional responses are all processed by the amygdala. So, this is why pain has such an influence on all of those abilities. This is why psychological pain is so much about the amygdala. And, as it seems, so is physical pain.

A new generation of pain killers?

Wang and her team found that GABA neurons found in the amygdala play a turn off/on button role. Gamma-Aminobutyric acid (GABA) is a neurotransmitter that reduces neuronal excitability in the nervous system. Turned off, the GABA neurons made mice experienced increased pain, whereas when the GABA neurons were turned on, the pain was suppressed.

“Our study points to [these GABAergic neurons] as a potential powerful therapeutic target for alleviating chronic pain,” said Wang.

The new goal for Wang is to find a way to transform her discovery into accessible means for people suffering from chronic pain to deal with this nightmare. For this to happen, the researchers must find a way into these cells. A gate that would act as a receptor for the alleged drugs.

“The other thing we’re trying to do is to sequence the hell out of these cells,” Wang said. Fingers crossed, Dr. Wang!