Simultaneous recordings revealed the characteristics of synaptic transmission from a single bipolar cell to a ganglion cell

s113

157

POSTSYNAPTiC

CA2+ ACCUMULATION

INTERNEURONS

IN THE CRICKET.

HIROTO OGAWA’, YOSHICHIKA

REGULATES

WIND-SENSITIVITY

OF CERCAL

GIANT

BABA’ AND KOTARO OKA’

‘Dept. Biol., Saitama Med. Sch., Moroyama-cho,

Saitama 3500436, ‘Neuro-Cybern.

Lab., Res. Inst. for Electronic

Science.

Hokkaido

Univ., Sapporo 0600812, ?Dept. of System Design Engin., Fat of Sci. and Tech, Keio Univ., Yokohama 2238522

Identified

wind-sensitive

giant interneurons

nals, and trigger an escape response. stimulation

of the presynaptic

thermore,

(GIs) in the cricket’s terminal abdominal

Continuous

air-puff stimulation

sensory neurons also attenuates EPSP amplitudes

the EPSPs evoked by the contra-lateral

lateral cereal nerves. This observation short-term

synaptic depression,

presynaptic

stimulation.

[Caz+]i elevation. depression.

suggests that this attenuation

The EPSP amplitude

Microinjection

depression

INTRACELLULAR

158

SYNAPTIC

YOSHIKAZU Integrative

Brain

At

synapses

stimulation(HFS) postsynaptic

under calcium

cells

have

whole-cell

NMDA

receptor

channel

blockers.

159 KO MATSUI,

elicited

by HFS those

granule

as well

to

induce

and have

here

greatly

increases

dentate

However,

been

with

enhanced

observed

RECORDINGS FROM

whole-cell

by disinhibition were

appear

L-type

to meet

which

high-frequency

is known

to require

dynamics

in dentate

slices in

from

young

rats

by

intracellular

calcium

picrotoxin,

a GABA,

with

depressed

by DL-AP-S.

voltage-dependent

the requirements

REVEALED

THE CHARACTERISTICS

BIPOLAR

CELL TO A GANGLION

A SINGLE

Depolarization

EPSCs revealed that the early and late components respectively.

and Sociology,

an

calcium

for the induction

OF SYNAPTIC CELL

bipolar- and ganglion-cell

pairs

of a bipolar cell induced a Ca“ current in the bipolar cell and and pharmacological

properties

of the evoked receptors

EPSCs were found to consist only of the non-NMDA

to the total evoked EPSC became large with increasing

the non-NMDA

and NMDA receptors

play distinct physiological

connected

of the evoked EPSC were mediated mainly by non-NMDA

of the NMDA component

These results suggest that non-NMDA

The University of Tokyo,

from synaptically

On the other hand, spontaneous

duration applied to the bipolar cell, whereas

that these receptors

significantly

cells,

calcium

in acute

Increases

or nimodipine,

here

patch recordings

of the newt retina.

The contribution

CELLS

606-8501

granule

these

examined

Flue-3.

in [Cal’],

as by verapamil

Kyoto

potentiation(LTP)

receptors.

imaging were

University,

evoked an EPSC in the ganglion cell. Analysis of the voltage dependence

component.

GRANULE

HOSOI and MASAO TACHIBANA

simultaneous

and NMDA receptors,

BY HIGH-FREQUENCY DENTATE

hippocampal

Department of Psychology, Graduate School of Humanities 7-3-l Hongo, Bunkyo-ku, Tokyo 113-0033

using slice preparation

synaptic

of the GIs via the

cells.

SIMULTANEOUS

We performed

without significant

the short-term

regulates the wind sensitivity

Kyoto

long-term

on NMDA

dynamics

TRANSMISSION NOBUTAKE

path

can

disinhibition,

The calcium

synaptic stimulation

ELICITED

of Medicine,

perforant

calcium

antagonist,

of LTP in dentate

DYNAMICS

School

unknown,

and

Ca” accumulation

To realize this

KATO

dependent

mostly

depression.

neuron also suppressed

IN RAT HIPPOCAMPAL

disinhibition

been

concentration([Ca*‘],) Under

the

influx

recording

antagonist.

CALCIUM

Graduate

from

short-term

Fur-

of the ipsi-

synapses.

NOBUO

Science,

giant intemeuron.

([Ca?‘]i) changes in the GIs excited by the

was not changed by subthreshold

STIMULATION

ISOMURA,

of the postsynaptic

is postsynaptic

of 50 mM BAPTA into the postsynaptic

at the cereal-to-giant

of the GIs. Tetanic

were attenuated by the tetanic stimulation

we examined the cytosolic Ca” concentration

These results indicate that the postsynaptic

short-term

granule

nerve stimulation

ganglion integrate cereal afferent sig-

decreased the wind-sensitivity

component distribute

roles in excitatory

was limited substantially differently

signal transmission

on the dendrites

pulse

by its desensitization. of a ganglion cell and

from bipolar cells to ganglion cells