RSS
Home
Discovery could explain ‘awakenings’ that occur with Ambien
Print
Email
RSS
Subscribe
A common FDA warning phrase: when taking this drug, do not operate large vehicles. Sound advice, but what if one does not even realize he is doing to the operating?
An interesting side effect of the sleep aid zolpidem (Ambien) is periods known as ‘awakenings.’ During an awakening, a person can do all types of normal activities ranging from eating breakfast to driving into work. Most will have no recollection of this state of semi-consciousness. And apart from being a potentially dangerous side effect, the cause of the awakenings was completely unknown.
Researchers from Georgetown University stumbled across the phenomenon while studying mice under the influence of the drug. They found that “while some powerful brain circuits are shut down with zolpidem, the powerful sedative activates other circuits when deprived of activity.” [EurekAlert] Instead of turning off the brain completely, a drug such as Ambien can actually turn on certain pathways, creating a state of ‘minimal consciousness.’
There are many types of neurons in the brain, including ones known as inhibitory neurons. These cells are responsible for keeping other neurons in check by slowing synapse firing rates. In the amygdala, an area of the brain that is involved with emotional reactions, inhibitory neurons are thought to temper impulsive traffic. But under the influence of zolpidem, these neurons do not function properly.
It acts as a type of cascade. According to Molly M. Huntsman, author of the study published in Proceedings of the National Academy of Sciences, “"When brain activity is silenced, many neurons automatically react to this change. We see this in our study which suggests that inhibitory neurons responsible for stopping neural activity are themselves shut down by zolpidem. The excitatory neurons, responsible for transmitting activity, are then allowed to re-awaken and become active again, without monitoring because the inhibitory neurons are 'asleep'." [EurekAlert]
The study employed mice whiskers to test the effects of zolpidem. Whiskers are an important source of sensory input for rodents. By cutting the whiskers of mice, scientists were able to monitor changes in the brain areas tied to whisker activity. With the removal of the whiskers’ brain stimulation, they found that inhibitory neurons underwent a surprising change with zolpidem was introduced. "After removing the whiskers and depriving neural activity, the inhibitory neurons that normally don't respond to sedation by zolpidem underwent a change, becoming more sensitive. The researchers posited that these neurons are shut down and, in turn, not able to monitor other brain circuits.” [EurekAlert]
How does this translate to the periods of awakenings? Researchers aren’t entirely certain. But it appears that “zolpidem shuts down active neural pathways and perhaps then triggers others.” [EurekAlert] That leads to the state of minimal conscious, the sudden activation of stimulatory neurons without the usual surveillance by inhibitory neurons. The brain is effectively functioning without an impulse checker.
Just how other circuitries are activated when the inhibitory neurons are shut down is unknown. "Nevertheless, the paradoxical activation of brain circuits by a powerful sedative definitely needs more attention in additional studies both human and in animal models," Huntsman concludes. [EurkeAlert] Undoubtedly true as the popularity of Ambien is ever-growing, and so the chance of potentially dangerous episodes of awakenings is increasing as well.
More science news: Childhood abuse linked to cancer * New source of stem cells * Advancing the safety of nanotechnology * More
More About:
biomedical science
Related Articles:
Comments
The medical journal The Lancet has retracted the 1998 article that was the first to link the MMR vaccine to autism. The withdraw comes hot on the …
.jpg)
On January 15th, the eastern hemisphere was treated to an annular solar eclipse. Check out images from that event (as well as one beautiful shot of a …
- 10. China's urbanization escalating strain on global grain supply
- 9. Life may have originated billions of years earlier
- 8. Against the odds ancient octopus fossils discovered
- 7.Scientist suggests that plant is self-aware
- 6. Girl with two hearts makes complete recovery
- 5. Evidence shows some large dinosaurs survived mass extinction
- 4. Potential cure found for honey bee colony collapse
- 3. New discovery may end transplant rejection
- 2.Successful treatment of peanut allergy
- 1. First clinical use of embryonic stem cells approved
