Major dopamine system helps restore consciousness after general anesthesia, study finds

July 22, 2014, American Society of Anesthesiologists

Researchers may be one step closer to better understanding how anesthesia works. A study in the August issue of Anesthesiology, the official medical journal of the American Society of Anesthesiologists (ASA), found stimulating a major dopamine-producing region in the brain, the ventral tegmental area (VTA), caused rats to wake from general anesthesia, suggesting that this region plays a key role in restoring consciousness after general anesthesia. Activating this region at the end of surgery could provide a novel approach to proactively induce consciousness from anesthesia in surgical patients, researchers say.

"While generally safe, it is well known that patients should not be under general anesthesia longer than necessary," said Ken Solt, M.D., lead author, Massachusetts General Hospital Department of Anesthesia, Critical Care and Pain Medicine and assistant professor of anesthesia, Harvard Medical School, Boston. "Currently, there are no treatments to reverse the effects of general anesthesia. We must wait for the anesthetics to wear off. Having the ability to control the process of arousal from general anesthesia would be advantageous as it might speed recovery to normal cognition after surgery and enhance operating room (O.R.) efficiencies."

Although the brain circuits that drive the process of emerging from general anesthesia are not well understood, recent studies suggest that certain arousal pathways in the brain may be activated by certain drugs to promote consciousness. The authors previously reported that methylphenidate (Ritalin), a drug used to treat attention deficit hyperactivity disorder, awakened rats from by activating dopamine-releasing pathways.

In the current study, rats were given the general anesthetics isoflurane or propofol. Once unconscious, researchers performed targeted , through implanted steel electrodes, on the two major regions of the rats' brains that contain dopamine-releasing cells – the VTA (the area of the brain that controls cognition, motivation and reward in humans) and the substantia nigra, which controls movement.

Researchers found that electrical stimulation of the VTA caused the rats to regain consciousness, suggesting that dopamine released from cells in this area of the brain is likely involved in arousal. Interestingly, electrical stimulation of the VTA had an effect similar to that of the drug methylphenidate in restoring consciousness after anesthesia.

"We now have evidence that dopamine released by cells in the VTA is mainly responsible for the awakening effect seen with methylphenidate," said Dr. Solt. "Because dopamine-releasing cells in the VTA are important for cognition, we may be able to use drugs that act on this region not only to induce in anesthetized patients, but to potentially treat common postoperative emergence-related problems such as delirium and restore cognitive function."

Explore further: Common stimulant may speed recovery from general anesthesia

Related Stories

Common stimulant may speed recovery from general anesthesia

September 21, 2011
Administration of the commonly used stimulant drug methylphenidate (Ritalin) was able to speed recovery from general anesthesia in an animal study conducted at Massachusetts General Hospital (MGH). The report, appearing in ...

Recovery from propofol anesthesia may be sped by use of common stimulant

April 5, 2012
The ability of the commonly used stimulant methylphenidate (Ritalin) to speed recovery from general anesthesia appears to apply both to the inhaled gas isoflurane, as previously reported, and to the intravenous drug propofol. ...

Study examines how brain 'reboots' itself to consciousness after anesthesia

June 18, 2014
One of the great mysteries of anesthesia is how patients can be temporarily rendered completely unresponsive during surgery and then wake up again, with all their memories and skills intact.

Rats' brains may 'remember' odor experienced while under general anesthesia

March 18, 2014
Rats' brains may remember odors they were exposed to while deeply anesthetized, suggests research in rats published in the April issue of Anesthesiology.

To recover consciousness, brain activity passes through newly detected states

June 9, 2014
Anesthesia makes otherwise painful procedures possible by derailing a conscious brain, rendering it incapable of sensing or responding to a surgeon's knife. But little research exists on what happens when the drugs wear off.

Common brain processes of anesthetic-induced unconsciousness identified

May 23, 2013
A study from the June issue of Anesthesiology found feedback from the front region of the brain is a crucial building block for consciousness and that its disruption is associated with unconsciousness when the anesthetics ...

Recommended for you

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

Miles Davis is not Mozart: The brains of jazz and classical pianists work differently

January 16, 2018
Keith Jarret, world-famous jazz pianist, once answered in an interview when asked if he would ever be interested in doing a concert where he would play both jazz and classical music: "No, that's hilarious. [...] It's like ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.