RT Journal Article
SR Electronic
T1 Cloning and characterization of chi-1: a developmentally regulated member of a novel class of the ionotropic glutamate receptor family
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 6498
OP 6508
DO 10.1523/JNEUROSCI.15-10-06498.1995
VO 15
IS 10
A1 AM Ciabarra
A1 JM Sullivan
A1 LG Gahn
A1 G Pecht
A1 S Heinemann
A1 KA Sevarino
YR 1995
UL http://www.jneurosci.org/content/15/10/6498.abstract
AB Ionotropic glutamate receptors are composed of homomeric or heteromeric configurations of glutamate receptor subunits. We have cloned a member of a novel class of the rat ionotropic glutamate receptor family, termed chi-1. This subunit exhibits an average identity of 27% to NMDA subunits and 23% to non-NMDA subunits. Regional transcript levels of chi-1 are elevated just prior to and during the first postnatal week, with the highest levels present in the spinal cord, brainstem, hypothalamus, thalamus, CA1 field of the hippocampus, and amygdala. The spatial distribution of chi-1 expression is similar from postnatal day 1 (P1) to adulthood. However, transcript levels decline sharply between P7 and P14 and remain attenuated into adulthood. Functional expression studies in Xenopus oocytes injected with in vitro transcribed chi-1 RNA did not demonstrate agonist-activated currents. Pairwise expression of chi-1 with members of the AMPA, KA, or delta class of glutamate recepto subunits either failed to generate agonist-activated currents or failed to alter the underlying current generated by the coexpressed subunit. However, coexpression of chi-1 with subunits forming otherwise functional NMDA receptors resulted in an inhibition of current responses. Since chi-1 did not alter the currents generated by non-NMDA subunits, this suggests that chi-1 may specifically interact with NMDA receptor subunits. Further characterization will be required to establish the precise role of this glutamate receptor subunit in neuronal signaling.