Featured Research

from universities, journals, and other organizations

Post-anesthesia dementia, like Alzheimer's, looks micro-'tubular'

Date:
June 27, 2012
Source:
Center for Consciousness Studies University of Arizona, Anesthesiology
Summary:
Modern anesthesia is extremely safe. But as risks to heart, lungs and other organs have waned, another problem has emerged in the elderly: post-operative cognitive dysfunction. Mentally, some patients “just aren’t the same” for months or longer after surgery. Other factors play a role, but a small number of patients deteriorate mentally due to anesthesia per se. Those with Alzheimer’s disease suffer exacerbations, and those without the diagnosis may have it unmasked by anesthesia, suggesting some relationship.

Modern anesthesia is extremely safe. But as risks to heart, lungs and other organs have waned, another problem has emerged in the elderly: post-operative cognitive dysfunction. Mentally, some patients "just aren't the same" for months or longer after surgery. Other factors play a role, but a small number of patients deteriorate mentally due to anesthesia per se. Those with Alzheimer's disease suffer exacerbations, and those without the diagnosis may have it unmasked by anesthesia, suggesting some relationship.

Related Articles


Alzheimer's disease has two types of brain lesions. Beta-amyloid deposits accumulate outside neurons but don't cause cognitive problems. Neurofibrillary tangles inside neurons, composed of hyper-phosphorylated 'tau', a protein normally attached to microtubules, do correlate with dementia. These same tau tangles are found in post-anesthesia dementia.

Microtubules (MTs) polymerize from 'tubulin' proteins to grow, shape and regulate neurons. Synaptic components are transported by motor proteins which move like railroad trains along MT tracks. In branching dendrites, motors change MTs repeatedly to reach their destination. Tau is a traffic signal, telling motors where to get on and off, the route encoded in MT binding sites for tau.

That MTs process information stems from Charles Sherrington in the 1950s, with recent controversial suggestions of MT computing, and even quantum computing mediating consciousness and memory. But whether MTs play a primary, or mere supportive role, their stability and function are essential to cognition and consciousness.

Excessive phosphorylation had been thought the culprit in detaching tau and causing tangles. But destabilized MTs now appear to be the primary problem in both Alzheimer's and post-anesthesia dementia, releasing tau which then becomes hyperphosphorylated. Anesthetics are known to bind to tubulin, in some cases for days after exposure, and in high doses to cause MT disassembly.

Now, in a study in PLoS ONE, a team from Canada, Portugal and the USA report molecular modeling showing 32 anesthetic binding sites per tubulin, with at least 1 percent (10 million) of the billion tubulins per brain neuron binding an anesthetic molecule at clinical concentration (1 'MAC'). Two particular anesthetic binding regions may destabilize MTs, one inactivating tubulin C-termini tails (which otherwise knit together neighboring tubulins). The other weakens side-to-side tubulin couplings, the critical link in MT lattices, but only at high anesthetic concentrations, or perhaps with other MT destabilizing factors (low temperature, low zinc, high calcium, acidosis).

Travis Craddock PhD, lead author on the study said: "The good news is that therapies aimed at microtubule stabilization may help in both Alzheimer's and post-anesthetic dementias. Clinical trials are underway, or planned, for microtubule stabilizers Epothilone D, NAPVSIPQ, and the zinc ionophore PBT2, as well as brain ultrasound, shown in vitro to excite MT resonances and promote polymerization. However it's done, 'tightening the tubules' may best treat dementia."


Story Source:

The above story is based on materials provided by Center for Consciousness Studies University of Arizona, Anesthesiology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Craddock TJA, St. George M, Freedman H, Barakat KH, Damaraju S, et al. Computational Predictions of Volatile Anesthetic Interactions with the Microtubule Cytoskeleton: Implications for Side Effects of General Anesthesia. PLoS ONE, 2012 DOI: 10.1371/journal.pone.0037251

Cite This Page:

Center for Consciousness Studies University of Arizona, Anesthesiology. "Post-anesthesia dementia, like Alzheimer's, looks micro-'tubular'." ScienceDaily. ScienceDaily, 27 June 2012. <www.sciencedaily.com/releases/2012/06/120627091617.htm>.
Center for Consciousness Studies University of Arizona, Anesthesiology. (2012, June 27). Post-anesthesia dementia, like Alzheimer's, looks micro-'tubular'. ScienceDaily. Retrieved January 27, 2015 from www.sciencedaily.com/releases/2012/06/120627091617.htm
Center for Consciousness Studies University of Arizona, Anesthesiology. "Post-anesthesia dementia, like Alzheimer's, looks micro-'tubular'." ScienceDaily. www.sciencedaily.com/releases/2012/06/120627091617.htm (accessed January 27, 2015).

Share This


More From ScienceDaily



More Mind & Brain News

Tuesday, January 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Technology Is Ruining Snow Days For Students

How Technology Is Ruining Snow Days For Students

Newsy (Jan. 25, 2015) More schools are using online classes to keep from losing time to snow days, but it only works if students have Internet access at home. Video provided by Newsy
Powered by NewsLook.com
Weird Things Couples Do When They Lose Their Phone

Weird Things Couples Do When They Lose Their Phone

BuzzFeed (Jan. 24, 2015) Did you back it up? Do you even know how to do that? Video provided by BuzzFeed
Powered by NewsLook.com
Smart Wristband to Shock Away Bad Habits

Smart Wristband to Shock Away Bad Habits

Reuters - Innovations Video Online (Jan. 23, 2015) A Boston start-up is developing a wristband they say will help users break bad habits by jolting them with an electric shock. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Amazing Technology Allows Blind Mother to See Her Newborn Son

Amazing Technology Allows Blind Mother to See Her Newborn Son

RightThisMinute (Jan. 23, 2015) Not only is Kathy seeing her newborn son for the first time, but this is actually the first time she has ever seen a baby. Kathy and her sister, Yvonne, have been legally blind since childhood, but thanks to an amazing new technology, eSight glasses, which gives those who are legally blind the ability to see, she got the chance to see the birth of her son. It&apos;s an incredible moment and an even better story. Video provided by RightThisMinute
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins