Expression of voltage‐dependent potassium channels in the developing visual system of Xenopus laevis

Abstract

Accumulating evidence suggests that voltage-dependent potassium (Kv) channels have important and varied roles in the development of neuronal and non-neuronal cell types. They have been implicated in processes such as proliferation, cell adhesion, migration, neurite outgrowth, and axon guidance. In this study, we used antibodies against several electrically active Kv channel alpha-subunits (Kv1-4) to describe the spatial and temporal expression patterns of Kv channel subunits in Xenopus laevis retinal ganglion cell (RGC) somata, axons, and growth cones. We found that RGCs express Kv1.3-, Kv1.5-, Kv3.4-, and Kv4.2-like subunits. Each subunit displayed unique cellular and subcellular distributions. Moreover, the expression patterns changed considerably over the major period of Xenopus retinal cell genesis and differentiation. Weak or no immunoreactivity was observed with antibodies against Kv1.1, Kv1.2, Kv1.4, Kv1.6, and Kv3.2 subunits in RGCs or other retinal cell types. In support of our previous pharmacologic evidence implicating Kv channels in RGC axon outgrowth, we found that Kv1.5-, Kv3.4-, and Kv4.2-like proteins, but not Kv1.3-like subunits, are abundantly expressed in RGC growth cones.

Brain Expression of Kv3 Subunits During Development, Adulthood and Aging and in a Murine Model of Alzheimer’s Disease

“…Since at the embryonic stage of life the FS phenotype is not yet present, the finding of such early expression of Kv3 suggests a novel role for these subunits before the appearance of mature firing competence. Very few studies concerning non-conventional functions of Kv3 channels have been published to date and were all focused on Kv3 involvement in cell proliferation (Chang et al 2003;Liebau et al 2006;Spitzner et al 2007;Miguel-Velado et al 2010), migration (Hendriks et al 1999) and neuronal growth cone extension (Pollock et al 2002). Our results underscore the need of further studies regarding the role of Kv3 currents in regulating neuronal and glial properties during the earliest phases of brain development.…”

Development of synapses and expression of a voltage-gated potassium channel in chick embryonic auditory nuclei

“…expressed in the initial segments of the spinal cord nor in the PNS of either rats or mice (Devaux et al, 2003). Kv channels may play a role in axon outgrowth in the retinal ganglion cells (Pollock et al, 2002). It is possible that Kv3.1 functions other than a channel during development.…”

TRPV2 Enhances Axon Outgrowth through Its Activation by Membrane Stretch in Developing Sensory and Motor Neurons

“…Identification of thermo TRP channel expression patterns during development would be important because it is well documented that some ion channels/receptors have two distinct and vital roles in embryonic and adult stages. For example, voltage-gated potassium channels regulate membrane excitabilities in adult neurons (Trimmer, 1998), whereas the channels have different roles during neural development such as regulation of cell proliferation, axon outgrowth, and neuronal maturation (Shibata et al, 2000;Pollock et al, 2002;Shibasaki et al, 2004;Liebau et al, 2006). It is also known that NMDA receptors regulate neural cell migration during development while their common role in adults is to act as key regulators for neural excitation (Nakanishi, 1992;Komuro and Rakic, 1993).…”