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CO2 chemoreception may be mediated by the modulation of certain ion channels in neurons. Kir4.1 and Kir5.1, two members of the inward rectifier K+ channel family, are expressed in several brain regions including the brainstem. To test the hypothesis that Kir4.1 and Kir5. 1 are modulated by CO2 and pH, we carried out experiments by expressing Kir4.1 and(More)
1. To understand the mechanisms which lead to acute neuronal swelling during anoxia, we studied the ionic movements of Cl- and Na+ during O2 deprivation in the hypoglossal (XII) neurons of rat brain slices using double-barrelled ion-selective microelectrodes. 2. Baseline extracellular Cl- and Na+ activities ([Cl-]o, [Na+]o) were 128.3 +/- 7.4 and 150.0 +/-(More)
CO2 chemoreception may be related to modulation of inward rectifier K+ channels (Kir channels) in brainstem neurons. Kir4.1 is expressed predominantly in the brainstem and inhibited during hypercapnia. Although the homomeric Kir4.1 only responds to severe intracellular acidification, coexpression of Kir4.1 with Kir5.1 greatly enhances channel sensitivities(More)
Rett syndrome caused by mutations in methyl-CpG-binding protein 2 (Mecp2) gene shows abnormalities in autonomic functions in which brain stem norepinephrinergic systems play an important role. Here we present systematic comparisons of intrinsic membrane properties of locus coeruleus (LC) neurons between Mecp2(-/Y) and wild-type (WT) mice. Whole cell current(More)
Depending on its severity and duration, O2 deprivation activates mechanisms that can lead to profound deleterious changes in neuronal structure and function. Hypoxia also evokes inherent adaptive mechanisms that can possibly delay injury and increase neuronal survival. One of these neuronal adaptive mechanisms is believed to be the activation of K+(More)
Ion channels play an important role in cellular functions, and specific cellular activity can be produced by gating them. One important gating mechanism is produced by intra- or extracellular ligands. Although the ligand-mediated channel gating is an important cellular process, the relationship between ligand binding and channel gating is not well(More)
The inward rectifier K(+) channels function in the regulation of myocardial rhythmicity, vascular tones, epithelial transport, and neuronal excitability. Most of these channels are gated by pH. It is now known that the gating process involves a large number of protein domains and amino acid residues in both N- and C-termini of the channel protein.(More)
Several inward rectifier K(+) (Kir) channels are inhibited by hypercapnic acidosis and may be involved in CO(2) central chemoreception. Among them are Kir1.1, Kir2.3, and Kir4.1. The Kir4.1 is expressed predominantly in the brainstem. Although its CO(2) sensitivity is low, coexpression of Kir4.1 with Kir5.1 in Xenopus oocytes greatly enhances the CO(2)/pH(More)
To determine the mechanisms underlying the depolarization induced by anoxia in brainstem neurons, we studied single neurons in brainstem slices using conventional micro-electrodes and freshly dissociated hypoglossal and vagal cells using patch clamp techniques (whole-cell configuration). Since glutamate concentration increases in the extracellular space(More)
1. Intracellular recordings were performed in human and rat neocortical neurons with in vitro brain slice techniques. Baseline cellular properties and the effect of O2 and glucose deprivation on these neurons were studied. 2. Intracellular labelings of electrophysiologically identified neurons showed that most neurons recorded from layers 4 and 5 of the(More)