M. Maammar et al., PERMEATION AND GATING OF ALPHA-1 GLYCINE-GATED CHANNELS EXPRESSED AT LOW AND HIGH-DENSITY IN XENOPUS OOCYTE, FEBS letters, 414(1), 1997, pp. 99-104
When a high density of alpha 1-subunit glycine receptor (GlyR) is expr
essed in Xenopus oocytes, two populations of channels can be distingui
shed according to their apparent affinity for glycine which differs 5-
to 6-fold, To compare the open pore diameter of these channels, the r
elative permeability of formate with respect to chloride (P-formate/P-
Cl) was determined in bionic conditions, For the low-affinity GlyR P-f
ormate/P-Cl was comparable to that reported for glycine-gated channels
in cultured spinal cord and hippocampal neurons, In contrast, the hig
h-affinity GlyR had a 56% larger P-formate/P-Cl, In addition, the open
probability of the channels was differentially sensitive to voltage,
These results show that the high expression of al GlyR resulted in two
populations of GlyR which differed not only in the affinity to agonis
ts but also in permeation and gating mechanisms. (C) 1997 Federation o
f European Biochemical Societies.