Neural pathways to regulate loss, regain consciousness during anesthesia identified

Researchers at the University of Pennsylvania School of Medicine have discovered two neural pathways that regulate loss and regain of consciousness during general anesthesia.

Washington, Jan 13: Researchers at the University of Pennsylvania School of Medicine have discovered two neural pathways that regulate loss and regain of consciousness during general anesthesia.

The team found that the cellular pathway for anesthesia is different from the one that drugs take to put patients to sleep during operations.

The study examined orexins, the small, specialized fraction of the brain's 100 billion neurons that played an imperative role in regulating the body's wakeful state.

The investigation led by Dr. Max B. Kelz, PhD, an assistant professor in Penn's Department of Anesthesiology and Critical Care and the Mahoney Institute of Neurological Sciences, was conducted on genetically engineered mice whose orexin systems was altered to put it into a state similar to humans suffering from narcolepsy, a neurological condition that causes unusual daytime sleepiness.

The findings revealed that the mice took much longer time to wake up from general anesthesia than those with normal orexin signaling systems.

On the other hand, mice with faulty orexin systems did not appear to fall asleep faster during anesthesia,

This suggested that different processes are involved in transitioning to and from the anesthetized state.

"The modern expectation is that anesthesiologists can simply flip a consciousness switch as easily as we might turn the room lights on or off," said Kelz.

"However, what patients do not realize is that despite 160 years of widespread clinical use, the mechanisms through which the state of anesthesia arises and dissipates remain unknown," he added.

The study has established for the first time that the process of entry into and exit from the anesthetized state are not mirror images of one another.

Researchers hope that further study on the brain's neural signalling systems will lead to novel ways to administer anesthesia and "jump start" a speedy, safe return to consciousness for people who struggle to wake up or are prone to anesthesia side effects.

The findings will be published this week in Proceedings of the National Academy of Sciences.

ANI