If you have ever had surgery, unless it was very difficult, you have gone through it with the benefit of anesthetics. Yet, how do these particles kill the body?
Before the invention of anesthesia in the mid-1800s, surgeons had to dissect limbs, sew wounds, and remove mysterious attachments without the use of opium or alcohol. While these drugs may have made the patient numb, they did not always completely control the pain, nor did they erase their memory.
Since then, doctors have become much better at relieving us with a combination of painkillers, muscle relaxants and, in some cases, placing us in a deep state of hypnosis that gives us temporary amnesia. Today, there are two main types of anesthetics: those that knock on the whole body (general) and those that only numb in the area.
Local anesthetics block the nerves that connect a specific part of the body or region to the brain, preventing the nerves from carrying pain signals to your brain. Examples include novocaine shots, dentists who use anesthesia in your mouth during the root canal, and epidurals, which allow for (painless) painless birth by blocking nerves from the bottom of the spinal cord and serving the pelvic region.
In complex surgeries that require the patient to be
completely unconscious, doctors turn to general anesthesia. This makes patients aware of nothing but vision or memory of the operation (although the pain of the surgical procedures will be evident when you wake up). It also limits the body's responses to surgical cuts, blood pressure, hormone release, and heart rate during the procedure.
Early examples of general anesthesia include ether and chloroform. However, there is a fine line between the amount of these drugs needed in surgery and the amount that can be fatal; these drugs were usually administered without a wet sponge in the nose, making it difficult to control the dose.
Today, the most common modern anesthetics are a combination of insoluble gases, including nitrous oxide (laughing gas) and various other ether compounds, such as Isoflurane, Sevoflurane, and desflurane. Specialists anesthesiologists prescribe these drugs with machines that measure the amount needed to keep a patient out for surgery, but not permanently. In addition, because the drugs interfere with breathing, patients are often inserted internally - meaning a plastic or rubber tube is inserted into the trachea to keep the air open - and stored in a ventilator.
In a study, from Neuron, researchers tracked this neural cycle in a small group of cells at the base of the brain responsible for releasing hormones to regulate body function, emotions, and sleep.
This discovery is the first to raise the role of hormones in maintaining normal anesthesia status, and it provides important information on the production of new drugs that can put people to sleep with fewer side effects.
Ever since the first patient went under general anesthesia in 1846, scientists have tried to figure out how it works. The prevailing view was that most of these drugs suppressed normal brain functions, resulting in inability to move or feel pain.
The same ideas related to sleep, the sister country is a general anesthesia. However, research over the past decade has shown that sleep is a more efficient process than ever before, with clusters of all the neurons entering the function while holding your Z's.
Fan Wang, a professor of neurobiology at Duke University School of Medicine, and Li-Feng Jiang-Xie, a graduate student in his laboratory, were wondering if the spectacular view of general anesthesia was so serious.
“Perhaps instead of blocking the nerves, the nerves can also use certain nerves in the brain,” says Jiang-Xie.
To test their new theory, Jiang-Xie and Luping Yin, an employee working behind the Wang lab, put mice under general anesthesia with various but widely used drugs. They then used cell markers to track the neurons commonly used by anesthetics.
They found a group of active neurons buried deep in a small area of the brain called the supraoptic nucleus, known as the official hypothesis that releases large amounts of hormones such as vasopressin directly into the bloodstream.
“Most of the neurotransmitters were a type of hybrid cell that connects the nervous system with the prostate gland,” says Jiang-Xie. "That surprised us and led us to an untested place to understand the emotional mechanisms of general anesthesia."
Next, researchers touched on a complex process performed on the Wang board to turn on or off this special group of cells with chemicals or light. When they release cells from mice, the animals stop moving and fall into a deep sleep called slow wave sleep, which is often accompanied by fainting.
The research team then killed the group of cells. The mice continued to move about, unable to sleep.
Finally, researchers performed similar tests on mice under general anesthesia. They found that making neuroendocrine cells before improper use made mice stay under normal anesthesia for a long time. On the other hand, when they silence these cells, mice easily wake up to anesthesia.
The study also revealed the unexpected role of brain cells in secreting hormones to promote deep sleep.
"A lot of people, especially those with Alzheimer's disease, have trouble sleeping, but current medications have side effects," Yin said. "If we can find ways to use this neural cycle, perhaps by identifying hormones or small peptides, that could lead to the development of better sleeping pills."
The WM Keck Foundation, the Brain Research Foundation, the National Institutes of Health, and the Human Frontier Science Fellowship sponsored the project.
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