High levels of ketamine can momentarily shutdown the brain
Researchers identified two brain phenomena that may explain the side effects of ketamine use.
The study conducted on a sheep that has been given doses of ketamine, provides an initial explanation of the experiences of depersonalization and the state of forgetfulness that is needed when using this drug (Nicol & Morton, 2020).
In a study aimed at understanding the effect of therapeutic drugs on the brains of people with Huntington’s disease, the researchers used electroencephalography to measure the immediate changes in the brain waves of animals once ketamine – an anesthetic and pain reliever drug – was given to them. While the sheep slept, low-frequency brain activity was recorded. When the drug vanished, and the sheep regained consciousness, there was an oscillation between the low and high frequency waves: these alterations were initially irregular, but became regular in a few minutes (Nicol & Morton, 2020). The onset of unusual patterns of brain activity of sheep corresponds to the time when, when a human subject takes ketamine, reports that he feels disconnected from his body; According to the researchers, brain swings caused by the drug are likely to prevent information from the outside world from being processed normally.
The findings emerged as part of a larger research project on Huntington’s disease, a condition that prevents the brain from functioning properly.
In the study in question, sheep were chosen as experimental subjects, because they are recognized as an adequate preclinical model of disorders of the human nervous system, including Huntington’s disease (Nicol & Morton, 2020). Six out of twelve sheep were given a higher dose of ketamine, 24 mg / kg, this dosage is considered anesthetic, however in reality a similar response is measured even with lower doses; within two minutes of administering the drug, the brain activity of five of the six sheep stopped completely, a phenomenon never seen before. Although the anesthetized sheep appeared to be asleep, their brain was actually turned off, but normal brain activity was recorded a few minutes later (Nicol & Morton, 2020).
The researchers believe that this pause in brain activity may correspond to what drug addicts describe as the “K hole”, a state of oblivion compared to a near-death experience, followed by a feeling of great serenity. The study was published in the journal Scientific Reports (Nicol & Morton, 2020).
It is known that drug addicts take doses often higher than those administered to sheep in this research; moreover (as in all drugs) the development of tolerance towards ketamine occurs, that is, in order to have the same effects it is necessary to take ever higher doses of the substance.
The physiological side effects that are often fatal when taking ketamine are irreversible liver impairment and cardiac arrest (Nicol & Morton, 2020).
Ketamine is widely used as a safe anesthetic for the treatment of large animals, including dogs, horses and sheep. It is also used in medicine, known as a ‘dissociative anesthetic’ since patients can appear awake and move, but do not feel pain and are unable to normally process information from the environment (Berman et al., 2000).
At lower doses, ketamine has a pain-relieving effect and its use in adults is mainly limited to military situations, especially to provide pain relief when a soldier is injured.
Ketamine has recently been proposed as a new treatment for depression and post traumatic stress disorder. Beyond its anesthetic actions, however, very little is known about the effects it causes on brain functions (Nicol & Morton, 2020).