Connexin and pannexin hemichannels of neurons and astrocytes.
Hemichannels are large pore ion channels that in the traditional view are formed when half a gap connexin junction opens to the extracellular space. It is now evident that other ion channel families, including the newly discovered pannexin family can form channels with all the nascent properties of hemichannels. This suggests that hemichannels should now be defined to include members of non-connexin families. Several connexin, and two pannexins are expressed in neurons and astrocytes where they may function in release of ATP and glutamate. Additionally, pannexin-1 appears to play a role in neuronal death. Hemichannels form a novel and unique class of ion channels that likely have diverse physiological and pathophysiological roles in the nervous system.
Department of Psychiatry and the Brain Research Center, University of British Columbia, Vancouver, British Columbia, Canada. neurophy@yahoo.com
Roger J
RJ
Thompson
Brian A
BA
Macvicar
D000818:Animals; D001253:Astrocytes / Q000737:chemistry* / Q000502:physiology; D017630:Connexins / Q000502:physiology; D006801:Humans; D007473:Ion Channels / Q000737:chemistry* / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000502:physiology; D009474:Neurons / Q000737:chemistry* / Q000502:physiology
D017630:Connexins; D007473:Ion Channels; D009419:Nerve Tissue Proteins; C492764:PANX1 protein, human