GABA receptor role in postoperative cognitive decline

About 20-30% of older adults (age greater than 60) undergoing major surgery experience temporary (generally reversed) memory and thinking deficits after major surgery, particularly heart and orthopedic. A small minority (<5%, probably much less) might not return to cognitive baseline (how they were before surgery). The cause of this decline in cognition is unclear, although many attribute it to the anesthesia used. So far, however, research has been inconclusive as to specific causes of cognitive difficulties after surgery. This is because surgeries are major events that affect most parts of the body, not just what is being operated upon. They are stressful – physically and emotionally.

Newly published research proposes one mechanism for causes of memory problems after surgery – anesthesia acting on ɣ-aminobutyric acid type A receptors (ɣ5GABAaR). This new research suggests that the function of these receptors does not return to baseline until much later than previously believed. This means that the normal function of chemicals in the brain, particularly ones important for memory, might be disrupted for longer than expected, and might play a role in memory problems that some individuals experience after major surgery.

Reference

Zurek, A. A., Yu, J., Wang, D. S., Haffey, S. C., Bridgwater, E. M., Penna, A., … & Orser, B. A. (2014). Sustained increase in ?5GABA A receptor function impairs memory after anesthesia. The Journal of clinical investigation, 124(12).

Post-operative Cognitive Dysfunction

Visit this link to my article on Brain Blogger to read a brief description of post-operative cognitive dysfunction (POCD). Here is a selection of what I wrote.

In the mid 1950s, Dr. Bedford reported on a number of older adults who exhibited cognitive problems (memory or planning or being able to sustain attention) following surgery where anesthesia was used. This effect is now called postoperative cognitive dysfunction (or decline; POCD). POCD typically lasts for a few months to a year with a small minority of patients exhibiting permanent decline. Studies about it were few at first, with most focusing on cognition following cardiac surgery. Over time and especially more recently, there has been an increase in research of POCD following non-cardiac surgeries (e.g., abdominal or orthopedic) as well as continued interest in POCD following cardiac surgery.

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Video site for watching surgeries

I’m quite fascinated by human anatomy, especially neuroanatomy. The human body is amazing; it’s something of a miracle that it develops and works as well and as often as it does. The brain is very complex with up to 100 million neurons (that’s also an estimate of the number of stars in our galaxy) and 100 trillion synapses (connections between neurons)! 100 trillion is an estimate of how many individual cells the entire human body has. We have as many synapses as cells in the entire body. The brain is complex and beautiful. It has symmetry but individuality.

I discovered a website that allows you to watch some surgeries live (or to view archives of past surgeries). OR-Live.com is informational and free. For those interested in neurosurgeries – everything from scoliosis surgery to tumor resection to deep brain stimulation – here is the direct link. Most of the videos are available in Flash format for web-viewing. Many are also available to download as a video podcast. Warning – please don’t watch the videos if you get queasy easily; if you feel queasy while watching one, take a break and do something else for a while.

I hope my readers enjoy this site as much as I have in the past and will continue to in the future.