In article <DvorakH-1503950927330001 at pinelab.caltech.edu>,
DvorakH at starbase1.caltech.edu (Hannah Dvorak) wrote:
> In article <jstream.1145216436A at 129.106.30.4>,
>jstream at girch1.med.uth.tmc.edu (Rifle River) wrote:
>> > In Article <3jksu3$ma8 at falcon.ccs.uwo.ca>, nkrenz at ctrg.rri.uwo.ca(Natalie
> > Krenz) wrote:
> > > I am trying to locate a reference as to whether or not there
are
> > >NMDA receptors on the presynaptic membrane. If anyone knows of any,
can
> > >you drop me a line?
> >
> > Sorry, no references, but I was told that there are definitely
glutamate
> > receptors on presynaptic terminals of the cells involved in LTP in
the
> > hippocampus. Good luck finding out if the presynaptic terminals have
NMDA
> > receptors.
>> As far as I know (from studying for quals in cell and molecular
> neurobiology a year ago) the glutamate receptors on the presynaptic
> terminals in the hippocampus are of the metabotropic kind.
>
Probably, you are talking the two series of papers appeared in Science a
few years ago. Here are their abstracts (from medline). As far as I
know, however, these reports are not accepted generally. Hope this
helps.
----------------------------------------------------------------------
<1>
Unique Identifier
94023987
Authors
Smirnova T. Stinnakre J. Mallet J.
Institution
Laboratoire de genetique moleculaire de la neurotransmission et des
processus neurodegeneratifs, Centre National de la Recherche
Scientifique
(CNRS), Gif sur Yvette, France.
Title
Characterization of a presynaptic glutamate receptor.
Source
Science. 262(5132):430-3, 1993 Oct 15.
Abstract
Glutamate receptors mediate excitatory neurotransmission in the brain
and
are important in the formation of memory and in some neurodegenerative
disorders. A complementary DNA clone that encoded a 33-kilodalton
protein
(GR33) was obtained by screening a library with an antibody generated
against glutamate binding proteins. The sequence of GR33 is identical
to
that of the recently reported presynaptic protein syntaxin. When GR33
was
expressed in Xenopus oocytes, it formed glutamate-activated ion
channels
that are pharmacologically similar to those of N-methyl-D-aspartate
receptors but with different electrophysiological properties. Mutation
of
the leucine 278 residue in the single putative transmembrane segment of
GR33 affects the properties of the channel. Thus, in vivo GR33 may be a
presynaptic glutamate receptor.
<2>
Unique Identifier
94023988
Authors
Smirnova T. Laroche S. Errington ML. Hicks AA. Bliss TV. Mallet J.
Institution
Laboratoire de genetique moleculaire de la neurotransmission et des
processus neurodegeneratifs, Centre National de la Recherche
Scientifique
(CNRS), Gif-sur-Yvette, France.
Title
Transsynaptic expression of a presynaptic glutamate receptor during
hippocampal long-term potentiation.
Source
Science. 262(5132):433-6, 1993 Oct 15.
Abstract
Repetitive activation of excitatory synapses in the hippocampus
produces a
persistent enhancement of synaptic efficiency known as long-term
potentiation (LTP). In anesthetized and in freely moving rats, the
induction of LTP in the perforant path led to a transient increase in
the
amount of messenger RNA (mRNA) coding for a presynaptic glutamate
receptor
(GR33) in dentate granule cells. The amount of GR33 mRNA was increased
for
at least 5 hours after the induction of LTP but was indistinguishable
from
control values 1 day after induction. The N-methyl-D-aspartate receptor
antagonist 2-aminophosphonovalerate prevented the induction of both LTP
and the increase in GR33 mRNA. The amount of GR33 protein was increased
in
the mossy fiber terminal zone of dentate granule cells 5 hours after
the
induction of LTP. These results suggest that the induction of LTP in
synapses at one stage in a neural network may lead to modification in
synaptic function at the next stage in the network.
----------------------------------------------------------------------
--
Yasunori Hayashi
Department of Neurophysiology, Institute for Brain Research
Faculty of Medicine, University of Tokyo, Japan
yhayashi at ims.u-tokyo.ac.jp
