(Press-News.org) When patients are put under anesthesia, they are often told they will be "put to sleep," and now it appears that in some ways that's exactly what the drugs do to the brain. New evidence in mice reported online on October 25 in Current Biology, a Cell Press publication, shows that the drugs don't just turn wakefulness "off," they also force important sleep circuits in the brain "on."
"Despite more than 160 years of continuous use in humans, we still do not understand how anesthetic drugs work to produce the state of general anesthesia," said Max Kelz of the University of Pennsylvania. "We show that a commonly used inhaled anesthetic drug directly causes sleep-promoting neurons to fire. We believe that this result is not simply a coincidence. Rather, our view is that many general anesthetics work to cause unconsciousness in part by recruiting the brain's natural sleep circuitry, which initiates our nightly journey into unconsciousness."
Kelz is himself an anesthesiologist, and he had long wondered just how accurate this notion of putting his patients to sleep really was. After all, there are important differences between natural sleep and the unconsciousness that comes with anesthesia. Even the soundest sleeper can be roused, while anesthetized patients maintain their slumber through the incredible insults that surgeries unavoidably bring.
In the new study, Kelz's team focused on a particular part of the brain, deep within the hypothalamus, which is known to increase in activity as one drifts off to sleep. Through a combination of direct electrical recording and other methods, they found that the anesthetic drug known as isoflurane boosts activity in this sleep-promoting brain area in mice. As further evidence of a connection, animals lacking the function of those neurons became more resistant to entering states of anesthesia.
The findings not only provide important clinical insights, but they might also go a long way toward reawakening our curiosity about anesthesia—to say nothing of the very mysterious nature of human consciousness itself.
"The development of anesthetic drugs has been hailed as one of humankind's greatest discoveries in the last thousand years," Kelz said. "Anesthetics are annually given to over 230 million patients worldwide. Yet as a society, and even within the anesthesia community, we seem to have lost our curiosity for how and why they work."
###
Moore et al.: "Direct Activation of Sleep-Promoting VLPO Neurons by Volatile Anesthetics Contributes to Anesthetic Hypnosis."
Anesthesia drugs really do put us to sleep
2012-10-25
ELSE PRESS RELEASES FROM THIS DATE:
Stanford researchers develop efficient, protein-based method for creating iPS cells
2012-10-25
STANFORD, Calif. — Coaxing a humble skin cell to become a jack-of-all-trades pluripotent stem cell is feat so remarkable it was honored earlier this month with the Nobel Prize in Physiology or Medicine. Stem cell pioneer Shinya Yamanaka, MD, PhD, showed that using a virus to add just four genes to the skin cell allowed it to become pluripotent, or able to achieve many different developmental fates. But researchers and clinicians have been cautious about promoting potential therapeutic uses for these cells because the insertion of the genes could render the cells cancerous.
Now ...
Genetic tradeoff: Harmful genes are widespread in yeast but hold hidden benefits
2012-10-25
ANN ARBOR— The genes responsible for inherited diseases are clearly bad for us, so why hasn't evolution, over time, weeded them out and eliminated them from the human genome altogether? Part of the reason seems to be that genes that can harm us at one stage of our lives are necessary and beneficial to us at other points in our development.
The idea that the same gene can be both beneficial and harmful, depending on the situation, is called antagonistic pleiotropy. The theory has been around since the 1950s and has been used to explain aging, cancer and genetic diseases.
But ...
Steroid injection linked to increased risk of bone fractures
2012-10-25
DETROIT – Patients treated with an epidural steroid injection for back pain relief are at increased risk of bone fractures in the spine, according to a Henry Ford Hospital study.
Researchers say the risk of fracture increased 29 percent with each steroid injection, a finding they believe raises patient safety concerns.
"For a patient population already at risk for bone fractures, steroid injections carry a greater risk that previously thought and actually pose a hazard to the bone," says Shlomo Mandel, M.D., a Henry Ford orthopedic physician and the study's lead author.
Dr. ...
Male competition over females
2012-10-25
When a female mates with several males, these will compete over the fertilization her eggs. This is an important evolutionary force that has led to the evolution of a diversity of male sexual organ morphologies. This is revealed in a study of seed beetles published today in the leading scientific journal Current Biology.
In higher plants, the influential classification system developed by Carl von Linnaeus relied on the fact that the reproductive parts of plants are evolutionarily stable. This is in sharp contrast to the reproductive organs of animals with internal fertilization, ...
Temple-Penn team identifies gatekeeper protein, new details on cell's power source
2012-10-25
(Philadelphia, PA) – Researchers at Temple University's Center for Translational Medicine and the University of Pennsylvania have identified a protein that serves as a gatekeeper for controlling the rush of calcium into the cell's power source, the mitochondria. Without this calcium spigot under control, calcium levels can run amok, contributing to cardiovascular disease, diabetes and neurodegeneration. The findings, reported online October 25, 2012, in the journal Cell, add important new insights into the inner workings of the mitochondria and may eventually help scientists ...
An animal model of typhoid fever could lead to better vaccines
2012-10-25
The first mouse model of the common bacterial disease typhoid fever is reported in a study published by Cell Press October 25 in the journal Cell. Because the animals show human-like symptoms and respond positively to immunization, they could be used to develop more effective vaccines against the deadly pathogen.
"Prior to our work, there was no small animal model for studying immune responses to the bacteria that cause typhoid fever," says study author Matthew Hayden of Columbia University. "We hope that the model we have developed will promote rapid progress in developing ...
Structure discovered for promising tuberculosis drug target
2012-10-25
Researchers at Johns Hopkins have figured out the three-dimensional shape of the protein responsible for creating unique bonds within the cell wall of the bacteria that cause tuberculosis. The bonds make the bacteria resistant to currently available drug therapies, contributing to the alarming rise of these super-bacteria throughout the world.
With the protein structure in hand, the scientists say, drug designers have a clear way forward for weakening the cell wall and killing these deadly bacteria. Their results are reported in a paper published online Oct. 25 in Structure.
"We've ...
Scientists create first mouse model of typhoid fever
2012-10-25
New York, NY (October 25, 2012) — Columbia University Medical Center (CUMC) researchers have created the first true mouse model of typhoid infection. The development promises to advance the study of typhoid and the creation of new vaccines against the infection, which remains a major health threat in developing countries. The paper was published today in the online edition of the journal Cell.
"Vaccines are the most practical solution for preventing typhoid in the Third World. Unfortunately, existing typhoid vaccines are only modestly effective, leaving millions of people ...
Resveratrol falls short in health benefits
2012-10-25
Resveratrol, an ingredient in red wine thought to improve insulin sensitivity, reduce risk of heart disease and increase longevity, does not appear to offer these benefits in healthy women, new research at Washington University School of Medicine in St. Louis indicates.
The study, reported online Oct. 25 in Cell Metabolism, involved 29 post-menopausal women who did not have type 2 diabetes and who were reasonably healthy. For 12 weeks, half took an over-the-counter resveratrol supplement, and the rest got a placebo, or sugar pill.
"Resveratrol supplements have become ...
Antibiotics that only partly block protein machinery allow germs to poison themselves
2012-10-25
Powerful antibiotics that scientists and physicians thought stop the growth of harmful bacteria by completely blocking their ability to make proteins actually allow the germs to continue producing certain proteins -- which may help do them in.
The finding, by a team at the University of Illinois at Chicago College of Pharmacy, clarifies how antibiotics work and may aid in the discovery of new drugs or improve clinical therapy with existing ones. The study is published in the Oct. 26 issue of the journal Cell.
Among the most complex molecular machines in the cell are ...