Oxytocin as neuro-hormone and neuro-regulator exert neuroprotective properties: A mechanistic graphical review

Linking oxytocin to nicotine dependence: An experimental study of the brain, behavior, and gut microbiota in rats

Oxytocin (OXT) is a hypothalamic neuropeptide, and numerous studies have indicated that exposure to addictive substances, such as opioids, cocaine, etc., can result in decreased function of the OXT system. The study also found that OXT can reduce addictive behavior for certain drugs, including methamphetamine, alcohol, and cocaine, suggesting a close relationship between the OXT system and drug abuse. Although nicotine is the main addictive substance in tobacco, its interaction with the OXT system is unknown and requires further study. Therefore, OXT levels in plasma and brain regions associated with addiction were measured by enzyme-linked immunosorbent assay (ELISA) using chronic nicotine administration via a slow-release pump. In addition, the effects of OXT injection on nicotine self-administration behavior, motor activity, and intestinal microbiota in rats were examined by nicotine self-administration experiment, open field experiment, and 16S sequencing experiment. By depleting gut microbiota with oral antibiotics, this study aims to investigate whether gut microbiota mediates oxytocin effect on the nicotine self-administration behavior in rats. This study shows that chronic nicotine administration can reduce OXT levels in plasma and brain regions such as the paraventricular nucleus (PVN), ventral tegmental area (VTA), and caudate putamen (CPU). OXT at a dose of 1.0 mg/kg significantly reduced the number of nicotine infusions and the abundance of Lactobacillus in rats. Notably, our findings indicate that other mechanisms besides gut microbes are involved in the effect of peripheral OXT administration on the inhibition of nicotine self-administration.

Caregiving is associated with lower brain age in humans

Middle-aged adults who are parents have better average cognitive performance and lower average brain age compared with middle-aged adults without children, raising the possibility that caregiving slows brain aging. Here, we investigate this hypothesis in two additional groups of caregivers: grandmothers and caregivers for people living with dementia (PLWD). Demographic, questionnaire, and structural Magnetic Resonance Imaging (MRI) data were acquired from n = 50 grandmothers, n = 24 caregivers of PLWD, and n = 37 non-caregiver controls, and BrainAGE was estimated. BrainAGE estimation results suggest that after controlling for relevant covariates, grandmothers had a brain age that was 5.5 years younger than non-grandmother controls, and caregivers of PLWD had brains that were 4.7 years younger than non-caregiver controls. Women who became grandmothers at a later age had lower brain age than those who became grandmothers at an earlier age. Among caregivers of PLWD, stress and caregiving burden were associated with increased brain age, such that the beneficial effect of caregiving on brain age was reduced in caregivers reporting more burden. Our findings suggest that caring for dependents may slow brain aging.

Dementia and neurodegenerative diseases: What is known and what is promising at the cellular and molecular level

Millions of people worldwide are affected by neurodegenerative diseases and cognitive impairment, which includes dementia, while there are only symptomatic treatments available for this syndrome at present. However, several important prospective drug targets have been identified in recent years that can potentially arrest or even reverse the progression of neurodegenerative diseases. Their natural or synthetic ligands are currently in the experimental stage of drug development. In vitro and preclinical (e.g. using animal models) studies confirm their therapeutic potential, but clinical trials often fail or produce conflicting results. Here, we first review the complexity and typology of dementia, followed by the discussion of currently available treatments, and, finally, some novel molecular and cellular approaches to this problem.

A review on polyamines as promising next-generation neuroprotective and anti-aging therapy

Neurodegenerative disorders are diseases characterized by progressive degeneration of neurons and associated structures and are a major global issue growing more widespread as the global population's average age increases. Despite several investigations on their etiology, the specific cause of these disorders remains unknown. However, there are few symptomatic therapies to treat these disorders. Polyamines (PAs) (putrescine, spermidine, and spermine) are being studied for their role in neuroprotection, aging and cognitive impairment. They are ubiquitous polycations which have relatively higher concentrations in the brain and possess pleiotropic biochemical activities, including regulation of gene expression, ion channels, mitochondria Ca2+ transport, autophagy induction, programmed cell death, and many more. Their cellular content is tightly regulated, and substantial evidence indicates that their altered levels and metabolism are strongly implicated in aging, stress, cognitive dysfunction, and neurodegenerative disorders. In addition, dietary polyamine supplementation has been reported to induce anti-aging effects, anti-oxidant effects, and improve locomotor abnormalities, and cognitive dysfunction. Thus, restoring the polyamine level is considered a promising pharmacological strategy to counteract neurodegeneration. This review highlights PAs' physiological role and the molecular mechanism underpinning their proposed neuroprotective effect in aging and neurodegenerative disorders.

Burst-Suppression EEG Reactivity to Photic Stimulation-A Translational Biomarker in Hypoxic-Ischemic Brain Injury

The reactivity of an electroencephalogram (EEG) to external stimuli is impaired in comatose patients showing burst-suppression (BS) patterns following hypoxic-ischemic brain injury (HIBI). We explored the reactivity of BS induced by isoflurane in rat models of HIBI and controls using intermittent photic stimulation (IPS) delivered to one eye. The relative time spent in suppression referred to as the suppression ratio (SR) was measured on the contralateral fronto-occipital cortical EEG channel. The BS reactivity (BSR) was defined as the decrease in the SR during IPS from the baseline before stimulation (SRPRE). We found that BSR increased with SRPRE. To standardize by anesthetic depth, we derived the BSR index (BSRi) as BSR divided by SRPRE. We found that the BSRi was decreased at 3 days after transient global cerebral ischemia in rats, which is a model of brain injury after cardiac arrest. The BSRi was also reduced 2 months after experimental perinatal asphyxia in rats, a model of birth asphyxia, which is a frequent neonatal complication in humans. Furthermore, Oxytocin attenuated BSRi impairment, consistent with a neuroprotective effect in this model. Our data suggest that the BSRi is a promising translational marker in HIBI which should be considered in future neuroprotection studies.

Mitochondrial might: powering the peripartum for risk and resilience

The peripartum period, characterized by dynamic hormonal shifts and physiological adaptations, has been recognized as a potentially vulnerable period for the development of mood disorders such as postpartum depression (PPD). Stress is a well-established risk factor for developing PPD and is known to modulate mitochondrial function. While primarily known for their role in energy production, mitochondria also influence processes such as stress regulation, steroid hormone synthesis, glucocorticoid response, GABA metabolism, and immune modulation - all of which are crucial for healthy pregnancy and relevant to PPD pathology. While mitochondrial function has been implicated in other psychiatric illnesses, its role in peripartum stress and mental health remains largely unexplored, especially in relation to the brain. In this review, we first provide an overview of mitochondrial involvement in processes implicated in peripartum mood disorders, underscoring their potential role in mediating pathology. We then discuss clinical and preclinical studies of mitochondria in the context of peripartum stress and mental health, emphasizing the need for better understanding of this relationship. Finally, we propose mitochondria as biological mediators of resilience to peripartum mood disorders.