Neuroscience
-
The hypothalamic paraventricular nucleus (PVN) plays a key role in hypertension, however the signaling pathways that contribute to the adaptability of the PVN during hypertension are uncertain. We present evidence that signaling at the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) GluA1 receptor contributes to increased blood pressure in a model of neurogenic hypertension induced by 14-day slow-pressor angiotensin II (AngII) infusion in male mice. It was found that AngII hypertension was associated with an increase in plasma membrane affiliation of GluA1, but decreased GluA2, in dendritic profiles of PVN neurons expressing the TNFα type 1 receptor, a modulator of AMPA receptor trafficking. ⋯ A further functional role for GluA1 in the PVN was demonstrated by the attenuated hypertensive response following silencing of GluA1 in the PVN of AngII-infused male mice. In female mice, AngII-infusion did not impact blood pressure or plasma membrane localization of GluA1. Post-translational modifications that increase the plasma membrane localization of AMPA GluA1 and heighten the rapid excitatory signaling actions of glutamate in PVN neurons may serve as a molecular substrate underlying sex differences in hypertension.
-
The primary motor cortex, a dynamic center for overall motion control and decision making, undergoes significant alterations upon neural stimulation. Over the last few decades, data from numerous studies using rodent models have improved our understanding of the morphological and functional plasticity of the primary motor cortex. ⋯ However, whether the modifications of specific synapses are associated with motor learning should be studied further. In this review, we summarized the findings of prior studies on the features and dynamics of the primary motor cortex in rodents.
-
The importance of morphological segmentation for reading has been shown in numerous behavioral studies in children and adults. However, little is known about developmental changes in the neural basis of morphological processing. In addition to effects of age and reading skill, morphological processing during reading may be affected by the morphological structure of the language and the transparency of its orthography. ⋯ These results diverge from a previous finding in adults, showing left frontal activation in the non-transparent script with the same stimuli. These results support the early sensitivity of young Hebrew readers to the rich morphological structure of their language but suggest a developmental change in the role of morphological processes during reading. While in adults morpho-phonological segmentation during reading may compensate for orthographic opacity, morphological processes in children may rely more on semantic aspects, and are enhanced by orthographic transparency.
-
We have recently shown that folate deficiency induces depression-like behavior and neuronal immaturity in the dentate gyrus (DG) in mice. We also revealed that folate deficiency inhibits neuronal maturation, hypomethylates the promoter of certain neuronal genes and decreases intracellular levels of S-adenosylmethionine (SAM), a methyl donor, in cultured neural stem and progenitor cells. Based on these findings, we hypothesized that SAM reduction may be involved in a folate deficiency-induced depressive state and neural immaturity. ⋯ Furthermore, neurofunctional and neuromorphological abnormalities in the DG of low folate diet-fed mice, such as decreases in stress-induced expression of c-Fos (a neuronal activity marker), dendritic complexity and the number of mature spines, were improved by SAM supplementation. The disrupted expression of transcription factors involved in neuronal differentiation and maturation was also normalized by SAM supplementation. These results suggest that SAM reduction may be involved in a folate deficiency-induced depressive state.
-
Ferroptosis, an iron-dependent form of non-apoptotic cell death, is reportedly responsible for cerebral ischemia/reperfusion (I/R) injury. Evidence has shown that spermidine/spermine N1-acetyltransferase 1 (SSAT1) activation-induced ferroptosis is associated with upregulation of arachidonate 15-Lipoxygenase (ALOX15). Our previous study has revealed that upregulation of ALOX15 contributes to cerebral I/R injury via inducing microglial activation. ⋯ Mechanistically, SSAT1 overexpression decreased the expression levels of two key ferroptotic repressors, glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) in TBH-stimulated neurons. Treatment with the ALOX15 inhibitor PD146176 or ferroptosis inhibitor ferrostatin-1 partially reversed SSAT1 upregulation-induced ferroptosis and viability loss in TBH-treated neurons. These results together indicate that the activation of SSAT1/ALOX15 axis may aggravate cerebral I/R injury via triggering neuronal ferroptosis, providing novel insights into cerebral injury associated with lipid peroxidation.