Neuroscience
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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.
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Large cholinergic neurons (V0c neurons; aka, partition cells) in the spinal cord project profusely to motoneurons on which they form C-terminal contacts distinguished by their specialized postsynaptic subsurface cisterns (SSCs). The V0c neurons are known to be rhythmically active during locomotion and release of acetylcholine (ACh) from their terminals is known to modulate the excitability of motoneurons in what appears to be a task-dependent manner. Here, we present evidence that a subpopulation of V0c neurons express the gap junction forming protein connexin36 (Cx36), indicating that they are coupled by electrical synapses. ⋯ We present evidence that fast vs. slow motoneurons have a greater abundance of these terminals and fast motoneurons also have the highest density that were eGFP+. Thus, our results indicate that a subpopulation of V0c neurons projects preferentially to fast motoneurons, suggesting that the capacity for synchronous activity conferred by electrical synapses among networks of coupled V0c neurons enhances their dynamic capabilities for synchronous regulation of motoneuron excitability during high muscle force generation. The eGFP+ vs. eGFP- V0c neurons were more richly innervated by serotonergic terminals, suggesting their greater propensity for regulation by descending serotonergic systems.