PHILADELPHIA — A new study by researchers at the Perelman School of Medicine at the University of Pennsylvania demonstrates in an animal model that a commonly used inhaled anesthetic drug, isoflurane, works by directly causing sleep-promoting neurons in the brain to activate, thereby hijacking our natural sleep circuitry. The findings are the latest work by investigators in the Center for Anesthesia Research at Penn who are exploring how anesthetics interact within the central nervous system to cause a state of unconsciousness. The new research is published the latest edition of the journal Current Biology.
"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 study author Max B. Kelz, MD, PhD, assistant professor of Anesthesiology and Critical Care. "We show in this new work 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 commandeering the brain’s natural sleep circuitry, which initiates our nightly journey into unconsciousness."
In the new study, Kelz and colleagues 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 isoflurane boosts activity in this sleep-promoting brain area in mice. As further evidence of a connection, animals lacking the function of those neurons exhibited acute partial resistant to entering states of anesthesia.
For more information, please see the Current Biology press release.