Neural excitatory rebound induced by valproic acid may predict its inadequate control of seizures

Analysis of the global burden of disease study highlights the global, regional, and national trends of idiopathic epilepsy epidemiology from 1990 to 2019

Epilepsy is a profound disorder, accounting for roughly 1% of the global disease burden. It can result in premature death and significant disability. To comprehensively understand the current dynamics and trends of idiopathic epilepsy, a deep insight into its epidemiological attributes is vital. We evaluated the incidence, prevalence, mortality, and disability-adjusted life years associated with idiopathic epilepsy from 1990 to 2019 using data and methodologies from the Global Burden of Disease Study. In 2019, there were approximately 2,898,222 individuals diagnosed with idiopathic epilepsy. Intriguingly, from 1990 to 2019, the age-standardized incidence rate of idiopathic epilepsy was consistently lower in women compared to men. Over these three decades, global mortality connected to idiopathic epilepsy increased by 13.95%. However, within the same period, age-standardized death rates for idiopathic epilepsy decreased from 1.94 per 100,000 population to 1.46 per 100,000 population. Predictions indicate an increase in the incidence of idiopathic epilepsy across all age brackets through 2035, especially among the elderly aged 80 and above. Mortality rates are projected to climb for those aged 80 and above while remaining relatively unchanged in other age demographics. Idiopathic epilepsy continues to be a significant contributor to both disability and death. The findings of our study underscore the critical importance of incorporating idiopathic epilepsy management into modern healthcare frameworks. Such strategic inclusion can enhance public awareness of relevant risk factors and the range of available therapeutic interventions.

Pain sensitivity related to gamma oscillation of parvalbumin interneuron in primary somatosensory cortex in Dync1i1-/- mice

Cytoplasmic dynein is an important intracellular motor protein that plays an important role in neuronal growth, axonal polarity formation, dendritic differentiation, and dendritic spine development among others. The intermediate chain of dynein, encoded by Dync1i1, plays a vital role in the dynein complex. Therefore, we assessed the behavioral and related neuronal activities in mice with dync1i1 gene knockout. Neuronal activities in primary somatosensory cortex were recorded by in vivo electrophysiology and manipulated by optogenetic and chemogenetics. Nociception of mechanical, thermal, and cold pain in Dync1i1^-/- mice were impaired. The activities of parvalbumin (PV) interneurons and gamma oscillation in primary somatosensory were also impaired when exposed to mechanical nociceptive stimulation. This neuronal dysfunction was rescued by optogenetic activation of PV neurons in Dync1i1^-/- mice, and mimicked by suppressing PV neurons using chemogenetics in WT mice. Impaired pain sensations in Dync1i1^-/- mice were correlated with impaired gamma oscillations due to a loss of interneurons, especially the PV type. This genotype-driven approach revealed an association between impaired pain sensation and cytoplasmic dynein complex.

Different oxytocin and corticotropin-releasing hormone system changes in bipolar disorder and major depressive disorder patients

Background

Oxytocin (OXT) and corticotropin-releasing hormone (CRH) are both produced in hypothalamic paraventricular nucleus (PVN). Central CRH may cause depression-like symptoms, while peripheral higher OXT plasma levels were proposed to be a trait marker for bipolar disorder (BD). We aimed to investigate differential OXT and CRH expression in the PVN and their receptors in prefrontal cortex of major depressive disorder (MDD) and BD patients. In addition, we investigated mood-related changes by stimulating PVN-OXT in mice.

Methods

Quantitative immunocytochemistry and in situ hybridization were performed in the PVN for OXT and CRH on 6 BD and 6 BD-controls, 9 MDD and 9 MDD-controls. mRNA expressions of their receptors (OXTR, CRHR1 and CRHR2) were determined in anterior cingulate cortex and dorsolateral prefrontal cortex (DLPFC) of 30 BD and 34 BD-controls, and 24 MDD and 12 MDD-controls. PVN of 41 OXT-cre mice was short- or long-term activated by chemogenetics, and mood-related behavior was compared with 26 controls.

Findings

Significantly increased OXT-immunoreactivity (ir), OXT-mRNA in PVN and increased OXTR-mRNA in DLPFC, together with increased ratios of OXT-ir/CRH-ir and OXTR-mRNA/CRHR-mRNA were observed in BD, at least in male BD patients, but not in MDD patients. PVN-OXT stimulation induced depression-like behaviors in male mice, and mixed depression/mania-like behaviors in female mice in a time-dependent way.

Interpretation

Increased PVN-OXT and DLPFC-OXTR expression are characteristic for BD, at least for male BD patients. Stimulation of PVN-OXT neurons induced mood changes in mice, in a pattern different from BD.

Funding

10.13039/501100001809National Natural Science Foundation of China (81971268, 82101592).