scholarly journals Could radical pairs play a role in xenon-induced general anesthesia?

2020 ◽  
Author(s):  
Jordan Smith ◽  
Hadi Zadeh Haghighi ◽  
Christoph Simon
Keyword(s):  
General Anesthesia ◽  
Radical Pair ◽  
The Body ◽  
Radical Pair Mechanism ◽  
General Anesthetic ◽  
Radical Pairs ◽  
Naturally Occurring ◽  
Isotopic Dependence ◽  
Anesthetic Potency ◽  
Recombination Dynamics

ABSTRACTUnderstanding the mechanisms underlying anesthesia would be a key step towards understanding consciousness. The process of xenon-induced general anesthesia has been shown to involve electron transfer, and the potency of xenon as a general anesthetic exhibits isotopic dependence. We propose that these observations can be explained by a mechanism in which the xenon nuclear spin influences the recombination dynamics of a naturally occurring radical pair of electrons. We develop a simple model inspired by the body of work on the radical-pair mechanism in cryptochrome in the context of avian magnetoreception, and we show that our model can reproduce the observed isotopic dependence of the general anesthetic potency of xenon in mice. Our results are consistent with the idea that radical pairs of electrons with entangled spins could be important for consciousness.

scholarly journals Radical pairs may play a role in xenon-induced general anesthesia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jordan Smith ◽  
Hadi Zadeh Haghighi ◽  
Dennis Salahub ◽  
Christoph Simon
Keyword(s):  
General Anesthesia ◽  
Radical Pair ◽  
The Body ◽  
Radical Pair Mechanism ◽  
General Anesthetic ◽  
Radical Pairs ◽  
Naturally Occurring ◽  
Isotopic Dependence ◽  
Anesthetic Potency ◽  
Recombination Dynamics

AbstractUnderstanding the mechanisms underlying general anesthesia would be a key step towards understanding consciousness. The process of xenon-induced general anesthesia has been shown to involve electron transfer, and the potency of xenon as a general anesthetic exhibits isotopic dependence. We propose that these observations can be explained by a mechanism in which the xenon nuclear spin influences the recombination dynamics of a naturally occurring radical pair of electrons. We develop a simple model inspired by the body of work on the radical-pair mechanism in cryptochrome in the context of avian magnetoreception, and we show that our model can reproduce the observed isotopic dependence of the general anesthetic potency of xenon in mice. Our results are consistent with the idea that radical pairs of electrons with entangled spins could be important for consciousness.

scholarly journals Entangled radicals may explain lithium effects on hyperactivity

2021 ◽  
Author(s):  
Hadi Zadeh-Haghighi ◽  
Christoph Simon
Keyword(s):  
Oxidative Stress ◽  
Magnetic Field ◽  
Cognitive Processes ◽  
Magnetic Field Dependence ◽  
Radical Pair ◽  
Lithium Treatment ◽  
Radical Pair Mechanism ◽  
Naturally Occurring ◽  
Isotopic Dependence ◽  
Recombination Dynamics

It is known that bipolar disorder and its lithium treatment involve the modulation of oxidative stress. Moreover, it has been observed that lithium's effects are isotope-dependent. Based on these findings, here we propose that lithium exerts its effects by influencing the recombination dynamics of a naturally occurring radical pair involving oxygen. We develop a simple model inspired by the radical-pair mechanism in cryptochrome in the context of avian magnetoreception and xenon-induced anesthesia. Our model reproduces the observed isotopic dependence in the lithium treatment of hyperactivity in rats. It predicts a magnetic-field dependence of the effectiveness of lithium, which provides one potential experimental test of our hypothesis. Our findings show that Nature might harness quantum entanglement for the brain's cognitive processes.

scholarly journals Entangled radicals may explain lithium effects on hyperactivity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hadi Zadeh-Haghighi ◽  
Christoph Simon
Keyword(s):  
Oxidative Stress ◽  
Magnetic Field ◽  
Cognitive Processes ◽  
Magnetic Field Dependence ◽  
Radical Pair ◽  
Lithium Treatment ◽  
Radical Pair Mechanism ◽  
Naturally Occurring ◽  
Isotopic Dependence ◽  
Recombination Dynamics

AbstractIt is known that bipolar disorder and its lithium treatment involve the modulation of oxidative stress. Moreover, it has been observed that lithium’s effects are isotope-dependent. Based on these findings, here we propose that lithium exerts its effects by influencing the recombination dynamics of a naturally occurring radical pair involving oxygen. We develop a simple model inspired by the radical-pair mechanism in cryptochrome in the context of avian magnetoreception and xenon-induced anesthesia. Our model reproduces the observed isotopic dependence in the lithium treatment of hyperactivity in rats. It predicts a magnetic-field dependence of the effectiveness of lithium, which provides one potential experimental test of our hypothesis. Our findings show that Nature might harness quantum entanglement for the brain’s cognitive processes.

scholarly journals Radical pairs may play a role in microtubule reorganization

2021 ◽  
Author(s):  
Hadi ZADEH-HAGHIGHI ◽  
Christoph Simon
Keyword(s):  
Magnetic Field ◽  
Radical Pair ◽  
Spin Dynamics ◽  
Radical Pair Mechanism ◽  
Magnetic Field Effects ◽  
Radical Pairs ◽  
Quantum Theories ◽  
Mechanism Model ◽  
Field Effects ◽  
Isotopic Dependence

The exact mechanism behind general anesthesia remains an open question in neuroscience. It has been proposed that anesthetics selectively prevent consciousness and memory via acting on microtubules (MTs). It is known that the magnetic field modulates MT organization. A recent study shows that a radical pair model can explain the isotope effect in xenon-induced anesthesia and predicts magnetic field effects on anesthetic potency. Further, reactive oxygen species are also implicated in MT stability and anesthesia. Based on a simple radical pair mechanism model and a simple mathematical model of MT organization, we show that magnetic fields can modulate spin dynamics of naturally occurring radical pairs in MT. We show that the spin dynamics influence a rate in the reaction cycle, which translates into a change in the MT density. We can reproduce magnetic field effects on the MT concentration that have been observed. Our model also predicts additional effects at slightly higher fields. Our model further predicts that the effect of zinc on the MT density exhibits isotopic dependence. The findings of this work make a connection between microtubule-based and radical pair-based quantum theories of consciousness.

Time-resolved studies of radical pairs

2009 ◽  
Vol 37 (2) ◽  
pp. 358-362 ◽  
Author(s):  
Jonathan R. Woodward ◽  
Timothy J. Foster ◽  
Alex R. Jones ◽  
Adrian T. Salaoru ◽  
Nigel S. Scrutton
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Chemical Reactions ◽  
Radical Pair ◽  
Radical Pair Mechanism ◽  
Magnetic Field Effects ◽  
Radical Pairs ◽  
Time Resolved ◽  
Field Effects ◽  
Field Sensitivity

The effect of magnetic fields on chemical reactions through the RP (radical pair) mechanism is well established, but there are few examples, in the literature, of biological reactions that proceed through RP intermediates and show magnetic field-sensitivity. The present and future relevance of magnetic field effects in biological reactions is discussed.

scholarly journals Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

2018 ◽  
Author(s):  
P. J. Hore
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Upper Bound ◽  
Prolonged Exposure ◽  
Radical Pair ◽  
Biological Effects ◽  
Radical Pair Mechanism ◽  
Childhood Leukaemia ◽  
Radical Pairs ◽  
Increased Risk

AbstractProlonged exposure to weak (~1 μT) extremely-low-frequency (ELF, 50/60 Hz) magnetic fields has been associated with an increased risk of childhood leukaemia. One of the few biophysical mechanisms that might account for this link involves short-lived chemical reaction intermediates known as radical pairs. In this report, we use spin dynamics simulations to derive an upper bound of 10 parts per million on the effect of a 1 μT ELF magnetic field on the yield of a radical pair reaction. By comparing this figure with the corresponding effects of changes in the strength of the Earth’s magnetic field, we conclude that if exposure to such weak 50/60 Hz magnetic fields has any effect on human biology, and results from a radical pair mechanism, then the risk should be no greater than travelling a few kilometres towards or away from the geomagnetic north or south pole.

scholarly journals Magnetic field effects in flavoproteins and related systems

2013 ◽  
Vol 3 (5) ◽  
pp. 20130037 ◽  
Author(s):  
Emrys W. Evans ◽  
Charlotte A. Dodson ◽  
Kiminori Maeda ◽  
Till Biskup ◽  
C. J. Wedge ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Blue Light ◽  
Radical Pair ◽  
Model Systems ◽  
Radical Pair Mechanism ◽  
Magnetic Field Effects ◽  
Radical Pairs ◽  
Chemical Systems ◽  
Field Effects ◽  
Blue Light Photoreceptor

Within the framework of the radical pair mechanism, magnetic fields may alter the rate and yields of chemical reactions involving spin-correlated radical pairs as intermediates. Such effects have been studied in detail in a variety of chemical systems both experimentally and theoretically. In recent years, there has been growing interest in whether such magnetic field effects (MFEs) also occur in biological systems, a question driven most notably by the increasing body of evidence for the involvement of such effects in the magnetic compass sense of animals. The blue-light photoreceptor cryptochrome is placed at the centre of this debate and photoexcitation of its bound flavin cofactor has indeed been shown to result in the formation of radical pairs. Here, we review studies of MFEs on free flavins in model systems as well as in blue-light photoreceptor proteins and discuss the properties that are crucial in determining the magnetosensitivity of these systems.

scholarly journals Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
PJ Hore
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Upper Bound ◽  
Prolonged Exposure ◽  
Radical Pair ◽  
Biological Effects ◽  
Radical Pair Mechanism ◽  
Childhood Leukaemia ◽  
Radical Pairs ◽  
Increased Risk

Prolonged exposure to weak (~1 μT) extremely-low-frequency (ELF, 50/60 Hz) magnetic fields has been associated with an increased risk of childhood leukaemia. One of the few biophysical mechanisms that might account for this link involves short-lived chemical reaction intermediates known as radical pairs. In this report, we use spin dynamics simulations to derive an upper bound of 10 parts per million on the effect of a 1 μT ELF magnetic field on the yield of a radical pair reaction. By comparing this figure with the corresponding effects of changes in the strength of the Earth’s magnetic field, we conclude that if exposure to such weak 50/60 Hz magnetic fields has any effect on human biology, and results from a radical pair mechanism, then the risk should be no greater than travelling a few kilometres towards or away from the geomagnetic north or south pole.

Stress management: Corpus-based insights into vernacular interpretations of stress

2014 ◽  
Vol 10 (1) ◽  
pp. 81-93
Author(s):  
Laurel Smith Stvan
Keyword(s):  
Traumatic Stress ◽  
American English ◽  
Physical Symptom ◽  
The Body ◽  
Post Traumatic Stress ◽  
The Past ◽  
Academic Texts ◽  
Naturally Occurring ◽  
Post Traumatic ◽  
Semantic Shift

Examination of the term stress in naturally occurring vernacular prose provides evidence of three separate senses being conflated. A corpus analysis of 818 instances of stress from non-academic texts in the Corpus of Contemporary American English (COCA) and the Corpus of American Discourses on Health (CADOH) shows a negative prosody for stress, which is portrayed variously as a source outside the body, a physical symptom within the body and an emotional state. The data show that contemporary speakers intermingle the three senses, making more difficult a discussion between doctors and patients of ways to ‘reduce stress’, when stress might be interpreted as a stressor, a symptom, or state of anxiety. This conflation of senses reinforces the impression that stress is pervasive and increasing. In addition, a semantic shift is also refining a new sense for stress, as post-traumatic stress develops as a specific subtype of emotional stress whose use has increased in circulation in the past 20 years.

scholarly journals General anesthesia with remimazolam in a patient with mitochondrial encephalomyopathy: a case report

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yuji Suzuki ◽  
Matsuyuki Doi ◽  
Yoshiki Nakajima
Keyword(s):  
Lactic Acidosis ◽  
General Anesthesia ◽  
Mitochondrial Disease ◽  
Muscle Relaxation ◽  
Anesthetic Management ◽  
Perioperative Period ◽  
Mitochondrial Encephalomyopathy ◽  
Anesthesia Induction ◽  
General Anesthetic ◽  
Anesthetic Agents

Abstract Background Systemic anesthetic management of patients with mitochondrial disease requires careful preoperative preparation to administer adequate anesthesia and address potential disease-related complications. The appropriate general anesthetic agents to use in these patients remain controversial. Case presentation A 54-year-old woman (height, 145 cm; weight, 43 kg) diagnosed with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes underwent elective cochlear implantation. Infusions of intravenous remimazolam and remifentanil guided by patient state index monitoring were used for anesthesia induction and maintenance. Neither lactic acidosis nor prolonged muscle relaxation occurred in the perioperative period. At the end of surgery, flumazenil was administered to antagonize sedation, which rapidly resulted in consciousness. Conclusions Remimazolam administration and reversal with flumazenil were successfully used for general anesthesia in a patient with mitochondrial disease.

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