Editors' ChoiceNeuroscience

What Is Behind the Secondary Inward Current?

Science Signaling  09 Dec 2008:
Vol. 1, Issue 49, pp. ec425
DOI: 10.1126/scisignal.149ec425

Hemichannels can form membrane channels that generate large ionic currents and allow the passage of small molecules across plasma membranes. Activation of N-methyl-D-aspartate (NMDA) receptors leads to a prolonged but unidentified secondary inward current. Thompson et al. now show that this current is likely to be due to pannexin-1 hemichannels. It seems excessive activation of NMDA receptors causes the opening of pannexin-1 channels, which then leads to an increase in bursting activity. This type of hemichannel might thus represent a target for the treatment of epilepsy and stroke.

R. J. Thompson, M. F. Jackson, M. E. Olah, R. L. Rungta, D. J. Hines, M. A. Beazely, J. F. MacDonald, B. A. MacVicar, Activation of pannexin-1 hemichannels augments aberrant bursting in the hippocampus. Science 322, 1555–1559 (2008). [Abstract] [Full Text]