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European Archives of Psychiatry and... Oct 2023Cognitive impairment has been observed in patients with various psychiatric disorders, including schizophrenia, major depressive disorder (MDD), and bipolar disorder... (Review)
Review
Cognitive impairment has been observed in patients with various psychiatric disorders, including schizophrenia, major depressive disorder (MDD), and bipolar disorder (BD). Although modern therapeutic drugs can improve certain symptoms (i.e., psychosis, depression) in these patients, these drugs have not been found to improve cognitive impairment. The N-methyl-D-aspartate receptor antagonist (R,S)-ketamine has attracted attention as a rapidly acting antidepressant. In addition to its robust antidepressant effects, (R,S)-ketamine has been suggested to improve cognitive impairment in patients with MDD and BD, despite causing cognitive impairment in healthy control subjects. (R,S)-ketamine is a racemic mixture of equal amounts of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine). Arketamine has been found to have more potent antidepressant-like actions than esketamine in rodents. Interestingly, arketamine, but not esketamine, has been suggested to improve phencyclidine-induced cognitive deficits in mice. Furthermore, arketamine has been suggested to ameliorate cognitive deficits in rodent offspring after maternal immune activation. In the current article, it is proposed that arketamine has therapeutic potential for treating cognitive impairment in patients with psychiatric disorders. Additionally, the potential role of the gut-microbiome-brain axis in cognitive impairment in psychiatric disorders is discussed.
Topics: Animals; Mice; Ketamine; Depressive Disorder, Major; Cognitive Dysfunction; Antidepressive Agents
PubMed: 36786865
DOI: 10.1007/s00406-023-01570-5 -
International Journal of Molecular... Sep 2023Sigma receptors are non-opiate/non-phencyclidine receptors that bind progesterone and/or heme and also several unrelated xenobiotics/chemicals. They reside in the plasma... (Review)
Review
Sigma receptors are non-opiate/non-phencyclidine receptors that bind progesterone and/or heme and also several unrelated xenobiotics/chemicals. They reside in the plasma membrane and in the membranes of the endoplasmic reticulum, mitochondria, and nucleus. Until recently, the biology/pharmacology of these proteins focused primarily on their role in neuronal functions in the brain/retina. However, there have been recent developments in the field with the discovery of unexpected roles for these proteins in iron/heme homeostasis. Sigma receptor 1 (S1R) regulates the oxidative stress-related transcription factor NRF2 and protects against ferroptosis, an iron-induced cell death process. Sigma receptor 2 (S2R), which is structurally unrelated to S1R, complexes with progesterone receptor membrane components PGRMC1 and PGRMC2. S2R, PGRMC1, and PGRMC2, either independently or as protein-protein complexes, elicit a multitude of effects with a profound influence on iron/heme homeostasis. This includes the regulation of the secretion of the iron-regulatory hormone hepcidin, the modulation of the activity of mitochondrial ferrochelatase, which catalyzes iron incorporation into protoporphyrin IX to form heme, chaperoning heme to specific hemoproteins thereby influencing their biological activity and stability, and protection against ferroptosis. Consequently, S1R, S2R, PGRMC1, and PGRMC2 potentiate disease progression in hemochromatosis and cancer. These new discoveries usher this intriguing group of non-traditional progesterone receptors into an unchartered territory in biology and medicine.
Topics: Ferroptosis; Receptors, sigma; Heme; Receptors, Progesterone; Iron; Homeostasis
PubMed: 37834119
DOI: 10.3390/ijms241914672 -
Cureus Nov 2023Ketamine is a phencyclidine (PCP) derivative, which primarily acts as a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. Ketamine serves as an analgesic... (Review)
Review
Ketamine is a phencyclidine (PCP) derivative, which primarily acts as a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. Ketamine serves as an analgesic and a dissociative sedative that produces potent analgesia, sedation, and amnesia while preserving spontaneous respiratory drive. It is rapidly gaining acceptance in the management of pain as multiple studies have demonstrated its reliable efficacy and a wide margin of safety. This article reviews some of these studies, the history of ketamine, and its pharmacological and pharmacokinetic properties. The article also discusses the use of ketamine in the trauma setting, including joint reductions, procedures, sedation, and pain control, as well as dosing recommendations.
PubMed: 37920424
DOI: 10.7759/cureus.48099 -
Heliyon May 2024Infectious diseases can contribute to substance abuse. Here, a fatal case of borreliosis and substance abuse is reported. This patient had a history of multiple tick...
BACKGROUND
Infectious diseases can contribute to substance abuse. Here, a fatal case of borreliosis and substance abuse is reported. This patient had a history of multiple tick bites and increasing multisystem symptoms, yet diagnosis and treatment were delayed. He experimented with multiple substances including phencyclidine (PCP), an N-methyl-d-aspartate (NMDA) receptor antagonist that opposes NMDA agonism caused by infection. During PCP withdrawal, he committed one homicide, two assaults, and suicide.
METHODS
Brain tissue was obtained from autopsy and stained for microglial activation and quinolinic acid (QA). Immunoflouresence (IFA) and fluorescence hybridization (FISH) were used to identify the presence of pathogens in autopsy tissue.
RESULTS
Autopsy tissue evaluation demonstrated in the pancreas by IFA and heart by IFA and FISH. Activated microglia and QA were found in the brain, indicating neuroinflammation. It is postulated that PCP withdrawal may exacerbate symptoms produced by -induced biochemical imbalances in the brain. This combination may have greatly increased his acute homicidal and suicidal risk. Patient databases also demonstrated the risk of homicide or suicide in patients diagnosed with borreliosis and confirmed multiple symptoms in these patients, including chronic pain, anxiety, and anhedonia.
CONCLUSIONS
Late-stage borreliosis is associated with multiple symptoms that may contribute to an increased risk of substance abuse and addictive disorders. More effective diagnosis and treatment of borreliosis, and attention to substance abuse potential may help reduce associated morbidity and mortality in patients with borreliosis, particularly in endemic areas.
PubMed: 38779029
DOI: 10.1016/j.heliyon.2024.e31159 -
CNS Neuroscience & Therapeutics Apr 2024As a phencyclidine (PCP) analog, ketamine can generate rapid-onset and substantial anesthetic effects. Contrary to traditional anesthetics, ketamine is a dissociative... (Review)
Review
BACKGROUND
As a phencyclidine (PCP) analog, ketamine can generate rapid-onset and substantial anesthetic effects. Contrary to traditional anesthetics, ketamine is a dissociative anesthetic and can induce loss of consciousness in patients. Recently, the subanaesthetic dose of ketamine was found to produce rapid-onset and lasting antidepressant effects.
AIM
However, how different concentrations of ketamine can induce diverse actions remains unclear. Furthermore, the molecular mechanisms underlying the NMDAR-mediated anesthetic and antidepressant effects of ketamine are not fully understood.
METHOD
In this review, we have introduced ketamine and its metabolism, summarized recent advances in the molecular mechanisms underlying NMDAR inhibition in the anesthetic and antidepressant effects of ketamine, explored the possible functions of NMDAR subunits in the effects of ketamine, and discussed the future directions of ketamine-based anesthetic and antidepressant drugs.
RESULT
Both the anesthetic and antidepressant effects of ketamine were thought to be mediated by N-methyl-D-aspartate receptor (NMDAR) inhibition.
CONCLUSION
The roles of NMDARs have been extensively studied in the anaesthetic effects of ketamine. However, the roles of NMDARs in antidepressant effects of ketamine are complicated and controversial.
Topics: Humans; Ketamine; Receptors, N-Methyl-D-Aspartate; Antidepressive Agents; Anesthetics
PubMed: 37680076
DOI: 10.1111/cns.14464