The Chloride Transporter Na⁺-K⁺-Cl⁻Cotransporter Isoform-1 Contributes to Intracellular Chloride Increases afterIn VitroIschemia

Abstract

Ischemic episodes in the CNS

Imaging synaptic inhibition in transgenic mice expressing the chloride indicator, Clomeleon

“…4a, open circles), as in Kuner and Augustine (2000), or by using the ionophores nigericin and tributyltin to equilibrate [Cl − ] i with extracellular [Cl − ] (Fig. 4a, filled circles), as in Pond et al (2006). In both cases, the ratio of Clomeleon fluorescence emission varied with [Cl − ] i and the two methods of manipulating [Cl − ] i yielded very similar titration curves.…”

“…Although these mice have previously been used for several purposes (Haverkamp et al, 2005;Duebel et al, 2006;Pond et al, 2006), this paper provides the first comprehensive description of these mice and the properties of the transgenically expressed Clomeleon. We also demonstrate that dynamic changes in [Cl − ] i resulting from synaptic activity can be detected in these mice, establishing a new avenue for imaging mechanisms of synaptic inhibition and inhibitory network activity.…”

“…In conclusion, the [Cl − ] i described here on the basis of non-invasive optical imaging supports the hypothesis that postnatal changes in the Cl − electrochemical gradient underlies the functional switch in GABAergic transmission during development. Pond et al, 2006). To stimulate the GABAergic interneurons that form inhibitory synapses with CA1 pyramidal neurons, we placed an extracellular electrode at the distal part of the apical dendrites (Freund and Buzsáki, 1996;Somogyi and Klausberger, 2005).…”

“…4a). Autofluorescence accounted 1.5% or less of the total fluorescence and did not have any significance on the calculated ratio (Pond et al, 2006). For the images shown in the figures, raw images were smoothed by Gaussian filter (size: 20 μm) twice and then divided.…”

“…Unlike organic Cl − dyes (Verkman, 1990), Clomeleon expression can be targeted to distinct populations of neurons. These properties make Clomeleon suitable for studying many poorly understood aspects of [Cl − ] i regulation, including activity-dependent ionic plasticity (Kaila, 1994;Payne et al, 2003), compartmental gradients of [Cl − ] i (Duebel et al, 2006;Szabadics et al, 2006), sensory signal transduction (Reuter et al, 1998), and pathophysiological mechanisms in a multitude of diseases (Payne et al, 2003;Pond et al, 2006).…”