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Role of auxiliary beta1-, beta2-, and beta3-subunits and their interaction with Na(v)1.8 voltage-gated sodium channel.

Publication Type:

Journal Article

Source:

Biochem Biophys Res Commun, Volume 319, Issue 2, p.531-40 (2004)

Keywords:

Animals, Blotting, Western, NAV1.8 Voltage-Gated Sodium Channel, Nerve Tissue Proteins, Patch-Clamp Techniques, Rats, Rats, Sprague-Dawley, Sodium Channels, Xenopus laevis

Abstract:

<p>The nociceptive C-fibers of the dorsal root ganglion express several sodium channel isoforms that associate with one or more regulatory beta-subunits (beta1-beta4). To determine the effects of individual and combinations of the beta-subunit isoforms, we co-expressed Nav1.8 in combination with these beta-subunits in Xenopus oocytes. Whole-cell inward sodium currents were recorded using the two-microelectrode voltage clamp method. Our studies revealed that the co-expression beta1 alone or in combination with other beta-subunits enhanced current amplitudes, accelerated current decay kinetics, and negatively shifted the steady-state curves. In contrast, beta2 alone and in combination with beta1 altered steady-state inactivation of Nav1.8 to more depolarized potentials. Co-expression of beta3 shifted steady-state inactivation to more depolarized potentials; however, combined beta1beta3 expression caused no shift in channel availability. The results in this study suggest that the functional behavior of Nav1.8 will vary depending on the type of beta-subunit that expressed under normal and disease states.</p>

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