Francis McClarnon
August 18, 2020
Ketamine and Neuroplasticity
A theory on how ketamine works.
So, what is ketamine and how does it work to treat depression and chronic pain? Well, ketamine has been around for a long time. It was first synthesized in the 60’s as an analog of phencyclidine or PCP. Phencyclidine was developed as an anesthetic agent but the psychotropic side effects (bad trip) were too great so it was not ever commonly used. So the scientists went back to the lab so to speak and changed some of its chemical properties and developed what we now know as ketamine.
Without going into much detail about all of the receptors in the brain that are effected by ketamine we can focus on the most important detail about how ketamine relieves the symptoms of depressive disorders and chronic neuropathic pain. The answer is nueroplasticity. A couple of years ago nueroplasticity was all over television and the internet. There were a bunch of websites that provided games for us to play that claimed to keep our brains sharp and young by improving our neuroplasticity. Now the root plasticity refers to the ability to ‘remodel” or change as in “plastic” surgery.
It was always believed in the health-science community that neuroplasticity was restricted to youth. That as we grow and develop we create new circuits in our brains as we learn new skills and gain new knowledge but as we mature that ability diminishes. But recent research has shown that not to be true and that even as adults we can gain new knowledge and skills and our brains can create new circuits and connections. These things may take longer to achieve but we can create these circuits.
Stress though can hinder neuroplasticity. In fact research has shown that emotional stress actually causes the brain to atrophy (deteriorate and become smaller) and reduce the number of connections between neurons. Something else that has been demonstrated through research is that individuals who have major depressive disorders like major depression and PTSD have connections and activity in regions of the brain associated with memory and concentration. Even one traumatic event can start this cycle of stress related brain atrophy.
There are some ways to reverse that atrophy and create new neurons and new connections in the brain. Some of the ways are things like exercising the body and mind; keeping yourself as fit as you can does improve neuroplasticity. taking selective serotonin reuptake inhibitors (SSRI’s) like Prozac, electroconvulsive therapy (ECT) and intravenous ketamine infusions. These things work by increasing the release of a growth factor in the brain called Brain Derived Neurotrophic Factor or BDNF. What BDNF does in the brain is stimulates the growth of new neurons and increases the number of connections of existing neurons.
Even though exercise
, SSRI medications like Prozac and ECT can increase the amount of BDNF in the brain, brain imaging studies have demonstrated that one intravenous infusion of low dose ketamine increases brain activity and neuronal connections in the brain. This explains why intravenous ketamine has such a rapid and robust effect on relieving the symptoms of major depressive disorders (MDD). Research has also demonstrated that intravenous ketamine infusions are also helpful in treating conditions like obsessive compulsive disorder and PTSD.
I can't help thinking that maybe the "flower children" of the 60's and seventies were on to something with their 'mind expanding" drugs.
Thanks for reading. I’m going to leave a link for a you tube video that goes into more detail. It was given by one of the researchers who started investigating intravenous ketamine therapy for major depressive disorders. It’s pretty easy to understand even for those who are not medical professionals.
Francis McClarnon CRNA, NP
August 21, 2020
https://youtu.be/hNsIiq-5354 Click the text to see the video.
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