I have been reading
Sykova E. (1991) "Activity-related ionic and volume changes in
neuronal microenvironment" in _Volume Transmission in the Brain_ (K.
Fuxe, L.F. Agnati, Eds.), pp 317-336, Raven Press, New York.
In that article, the following statement is made:
"[Extracellular] K+ accumulation has been accepted as one of two
causal factors (together with GABA) in primary afferent
depolarization, which is the mechanism underlying presynaptic
inhibition. It is assumed that the increase in [K+]e that is
associated with repetitive neuronal activity reduces transmitter
release by curtailing the presynaptic spike amplitude by presynaptic
Could someone please explain this statement? How does presynaptic
depolarization reduce the presynaptic spike amplitude? Seems like it
should enhance it.
Please reply to the neuroscience at net.bio.net list or email me
directly, as my site doesn't receive every bionet.neuroscience posting
for some reason.
John E. Anderson
W. M. Keck Structural Biology Laboratory
Cold Spring Harbor Laboratory