Connexin Hemichannels in Astrocytes: An Assessment of Controversies Regarding Their Functional Characteristics

Brian Skriver Nielsen, Daniel Bloch Hansen, Bruce R. Ransom, Morten Schak Nielsen, Nanna MacAulay*

*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

21 Citationer (Scopus)

Abstract

Astrocytes in the mammalian central nervous system are interconnected by gap junctions made from connexins of the subtypes Cx30 and Cx43. These proteins may exist as hemichannels in the plasma membrane in the absence of a ‘docked’ counterpart on the neighboring cell. A variety of stimuli are reported to open the hemichannels and thereby create a permeation pathway through the plasma membrane. Cx30 and Cx43 have, in their hemichannel configuration, been proposed to act as ion channels and membrane pathways for different molecules, such as fluorescent dyes, ATP, prostaglandins, and glutamate. Published studies about astrocyte hemichannel behavior, however, have been highly variable and/or contradictory. The field of connexin hemichannel research has been complicated by great variability in the experimental preparations employed, a lack of highly specific pharmacological inhibitors and by confounding changes associated with genetically modified animal models. This review attempts to critically assess the gating, inhibition and permeability of astrocytic connexin hemichannels and proposes that connexins in their hemichannel configuration act as gated pores with isoform-specific permeant selectivity. We expect that some, or all, of the controversies discussed here will be resolved by future research and sincerely hope that this review serves to motivate such clarifying investigations.

OriginalsprogEngelsk
TidsskriftNeurochemical Research
Vol/bind42
Udgave nummer9
Sider (fra-til)2537–2550
Antal sider14
ISSN0364-3190
DOI
StatusUdgivet - sep. 2017

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