Activation of NMDA receptors changes the location of drebrin in dendritic spines

s109

145 NOBUAKI

FUNCTIONAL

EXPRESSION

HIPPOCAMPAL

NEURONS

OF

MUTATED

NMDA

USING ADENOVIRAL

SUDO’,3, HARUO OKADO 2.3,MASAE

YAMADA’m3, MAKOTO

RECEPTOR

CHANNELS

IN

CULTURED

MIWA2,3, KEISUKE

TSUZUKP3,

VECTORS. IINOL,3, AKIKO

SEIJI OZAWA’,3 ‘Dept. of Physiol.,

Gunma Univ. Sch. of Med., Maebashi

371-8511, ‘Dept. of Neurobiol.,

Fuchu, Tokyo 183-8526, 3CREST, Jpn Sci.&Tech. Corp., Minatoku, To express

recombinant

encoding

NRl,

replaced

with arginine

functional

NRl(N598R)

expressions

NRl(N598R)/NR2B with

receptor

channels

(R) by site-directed of heteromeric

thus

the adenoviruses

bearing

reduced.

MASAHARU

KUDOH,

receptors

were

permeable

and insensitive

Both

RECEPTORS

by the adenoviral

three

recombinant

adenoviruses

in N-site of the wild type NRl patch

clamp

receptors

in PC12

to

and

Ca”

technique,

we examined

cells co-infected

blocked

by

was

with the

Mg*‘,

whereas

Next, we infected cultured rat hippocampal

to Mg*+.

and NRZB.

introduced

Inst. Neurosci.,

Ca2’ permeability

and Mg*+ block

also became less sensitive

vectors function as postsynaptic

IN THE INDUCTION

OF INPUT-SPECIFIC

in NMDA We

to Mg*‘. receptors.

LONG-TERM

IN THE RAT AUDITORY CORTEX

MASASHI

Dept. of Neurophysiology,

the whole-cell

and NRl(N598R)/NR2B

NRl(N598R)

ROLES OF GLUTAMATE DEPRESSION

asparagine

The slow EPSC mediated by NMDA receptors

conclude that the NRl(N598R)/NR2B

146

Using

expressed

receptors were Ca 2’-impermeable

receptors were markedly

In NRl(N598R),

mutagenesis.

NRl/NRZB

receptors

we constructed

in CNS neurons,

and NRBB, respectively.

NRVNRZB

adenoviruses.

neurons

NMDA

Tokyo Metropolitan

Tokyo 105-0011, Japan

SAKAI, KATSUEI

SHIBUKI

Brain Research Institute, Niigata University,

Roles of glutamate receptors in the induction of long-term depression

Niigata 95143585, Japan

(LTD) of field potentials or EPSPs were studied in the

slices obtained from the adult rat auditory cortex. LTD in supragranular

layers was elicited by low frequency

stimulation (I Hz

for 15 min) of layers III or of layer IV/white matter. LTD evoked by layer III stimulation was completely blocked by 50 pM DAPV, a blocker of NMDA receptors.

However,

LTD evoked by layer IV/white matter stimulation was only partially blocked by

D-APV, and the remaining LTD was blocked by D-APV plus 500 pM MCPG, a nonspecific glutamate receptors such as mGluR1 and mGluR5.

antagonist of metabotropic

LTD evoked by layer IV/white matter stimulation

by D-APV plus 300 pM L-AP3, an antagonist of mGluR1 and mGluR5.

However,

was completely blocked

it was only partially blocked by D-APV

plus 300 pM AIDA, an antagonist of mGluR1, or by D-APV plus 1 mM CPPG, an antagonist of group II/III mGluRs. magnitude of LTD in the presence of these drugs was not significantly

These findings suggest that induction of LTD is dependent on NMDA receptors in the pyramidal-pyramidal mGluR5 in the thalamo-pyramidal ACTIVATION

147

DENDRITIC

YUKO SEKINO,

YINHUAN

the functions

and on

NMDA

RECEPTORS

CHANGES

THE

LOCATION

OF

DREBRIN

IN

XUE, TOMOAKI SHIRAO and Behavior. Gunma University School of Medicine, Maebash]. Gunma 37 I-85 I I

Drebrin is a developmentally mainly in the cytosome,

OF

synapses,

in the auditory cortex.

SPINES

Department of Neurobiology

understand

synapses

The

different from that in the presence of D-APV alone.

regulated neuron-specific

axon and dendrites.

actin binding protein.

In adult cortical neurons,

of drebrin in the spines,

In developing

neurons.

drebrin is expressed

drebrin is mainly localized in dendritic spines.

we examined the effects of synaptic stimulation

To

on drebrin distribution.

Glutamate and/or glutamate receptor blockers were applied to Z-week rat cerebral cortical primary cultures prepared from 30. day embryos.

Two hours after application,

the confocal microscope. the application drebrin

cells and examined the IocaliLation of drebrin in spines u ith

Our results show that the application of glutamate weakened

of a NMDA receptor antagonist,

localization

glutamatergic

we immunostained

in spines,

These observation

synaptic transmission

DL-amino-S-phosphonovaleric suggest

drebrin localization in spines,

acid. blocked this glutamatergic

that the localization of drcbrin

and may play a role in long teim potentiation.

in spines

while

effect on

is directly related to