Plug. NeumPsyhDphanmcni d i3bl Psychcat F.&ted In Geat Brttaln. Au rt&ta rue-d

1992. Vol.

16.pp.56l-670

0278 - 5846/92 e 1982 ~ergamon

816.00

Prcu Ltd

INFLUENCE OF THE ACUTE STRESS ON AGONIST-STIMULATED PHOSPHOINOSITIDE HYDROLYSIS IN THE RAT CEREBRAL CORTEX SHIGERU NAOYUKI

MORINOBU' OKUYAMAl,'

'Department Yamagata

TOMIKO NORIHIKO KUWAYAMA' f* SHIRO MICHIHIRO TAKAHAS and MASAO ENDOH ?'

of Neuro-Psychiatry, University School

(Final

KAWANAM T", TOTSUKA

'Department of Pharmacology, of Medicine, Yamagata, Japan

form,

October

1991)

Abstract Naoyuki Okuyama, Tomiko Kawanami, Shigeru, Norihiko Kuwayama, Morinobu, Shiro Totsuka and Masao Endoh: Influence of the Acute Michihiro Takahashi, Stress on Agonist-Stimulated Phosphoinositide Hydrolysis in the Rat Cerebral Neuro-Psychopharmacol. & Biol. Psychiat. 1992, 16(4):561-570. Cortex. Prog. 1.

2.

3.

4. 5.

out in order to elucidate the influence The present study was carried serotonin-2 (5-HT2) and muscarinic of the acute stress on al-adrenergic, cholinergic (M-Ach) receptors-mediated phosphoinositide (PI) hydrolysis in rat cerebral cortex slices. In rat cerebral cortex slices, noradrenaline (NA), serotonin (S-HT) and (IPI) accumulation in a [3H]'lnositol-monophosphate carbachol stimulated concentration-dependent manner. The forced swimming tegt (FST) for 15 min induced a significant reduction of 5-HT-stimulated [ H]IPl accumulation, but this stress situation d'd not produce a significant alteration of NA- and carbachol-stimulated ['H]IP accumulation. The F B T for 15 min did not affect the density and affinity of al5-HT2 and M-Ach receptors. adrenergic, In a mild acute stress situation, the intracellular signal transduction mediated by 5-HT was promptly inhibited as compared to the signal transduction mediated by NA or carbachol. This inhibition may be induced by an acute uncoupling of 5-HT2 receptor-mediated intracellular signal transduction.

Keyword: cortex,

al-adrenergic receptor, phosphoinositide muscarinic receptor, serotonin-2 receptor,

hydrolysis, stress

rat

cerebral

Abbreviation: forced swimming test (FST), inositol-monophosphate (IPI), noradrenaline (NA), phosphoinositide (PI), diacylglycerol (DAG), protein kinase C (PKC), muscarinic cholinergic (M-Ach), serotonin (5-HT), trichloracetic acid (TCA)

Introduction Investigations nervous of

affective

carbonate therapeutic found

of

system

that

accumulation

is

the

have

therapeutic

opened

a new

disorder.

Although

effective

in

mechanism lithium in

the

has

the long

amplified rat

brain

mechanism field it

to

has

been

treatment been

of

the

of

unknown.

agonist-stimulated (Allison 561

et

al

lithium

research well the

action in

recognized affective

Allison

in

the

central

pathogenesis that

lithium

disorder,

and

his

it's

co-workers

myo-inositol-mono-phosphate 1976).

Berridge

and

his

co-

S. MorInobu et aL

562

workers

have

phosphatase al

1982,

activity

shown

that

and

suppressed

1983).

Recently,

of

the

Rasenick

These

1990).

messenger

system

may

in

the

rat

findings play

an

the

been

rat

that role

to

cortex

al

disorder

of

the et

the

function

1988,

Ozawa

the

et

inhibit

(Avissar

affect et

in the

(Berridge

shown

brain

(Yamaoka

suggest

inositol-mono-

metabolism

likewise

brain

important

enzyme,

(PI) has

antidepressants

in

the

carbonate

protein

some

proteins

inhibits

phosphoinositide

lithium

GTP-binding

Furthermore,

1988).

GTP-binding

lithium the

al of and

intracellular

pathogenesis

of affective

disorder. In

the

with by

clinical

affective the

and

Reinhard

et

various

1991).

et

al

These

induction

the

of

findings

PI

subcellular

rat

of

cerebral

of

forced

swimming

induced

by

the

involvement

has

the

the

the

stress

in

in order

cortex

of

(Morgan

al

1988,

stress

situation

et

al

Imperato

situation

of

the

focus

that

of

acute

to

have

of

in

stress much

on

less

the

modulation

of

may

be

involved

in

to

disorder.

changes

the

patients preceded

studies

et

the

in been

in neurotransmitter

influence

been

al-adrenoceptors

slices

test

Estevex

implicate

affective

receptors,

cortex

cerebral

transduction

investigated

(5-TH2)

rat

the

in

that

often

changes

1983,

Although

observations

mechanism

authors

al

indicate

has

pharmacological induce

in et

noted

illness

addition,

disorder.

hydrolysis

have

their

situations

Tanaka

previous

receptor-mediated

The

1982.

signal

the

serotonin2

In

stress

affective

intracellular

attention,

the

psychiatrists

onset

neurotransmitter-receptors

1975, al

the

situation.

that

release

the

disorder

stress

elucidated

observation,

PI

hydrolysis

coupled

and

muscarinic

receptors

stress

investigate

situation

the

changes

induced of

in

by

the

PI metabolism

stress.

Methods Animals Male

standard

Japanese and

Wistar

Chales

water

River

available

rats

(weighing

Company. ad

Rats

200

ca.

were

housed

g) five

were per

purchased cage

and

from fed

food

libitum.

Drugs 5-HT

creatinine

bovine

albumin

Ci/mmol) Ci/mmol)

and

Tissue

(85

ACS-II

were

(77.8

chemicals Preparation

atropine,

purchased

[3H]prazosin

[3H]Ketanserin other

sulfate,

were

were

from

uCi/mmol) purchased

Ci/mmol)

was

purchased

from

and

[3H]IPl

Rats

were

decapitated,

slices

(350

urn) prepared

their from

pargyline

noradrenaline, Sigma

Chemical

Co.

from

Amersham

Wako

from

Chemical

serum (18.3 (77.8

Radiolabeled New

and

benzylate

[3H]quinuclidinyl

purchased

HCl

[3H]Myo-inositol

England

Chemicals. Nuclear.

All

Co.

Accumulation brains the

immediately

cerebral

cortex

removed (mainly

and

cross-chopped

frontal).

Slices

Acutestressandagonist-sllmulatedP1hydrolysis

were

preincubated

bilated

with

[3H]Inositol al.

(1982,

after

the

with for

of

1

an

agonist min

ml

of

51

Slices

were

750

of

the

750

ul.

aliquot

of

viously

collected

were

formate/lOO of

After mine

and the

the

inositol

of

After

was of

40,000

pellets

x g at the

of

Greengrass

ferred

The

buffer

by

addi-

mixtures

were was

centrifuged. to

collected

An

the

pre-

supernatant

dietylether. Dowex-1 eluted

the

resin with

(100-200

200

mM

were

et

pellets

total

mesh:

ammonium

added

a1.(1951)

Tissue

for

the

The into

over

were

taken

incorporation

slices.

of

The

to 8 ml

the the

did

basal

3

HImy+

measured

of

[3H]myo-

not

All

deter-

[

was

estimation

slice.

to

of

protein

agonist

al.

(1983)

method

pH

vials

50

were

the

and

affect

the

results

[3H]IPl

were

levels

of

and

binding

was

Yamamura at

25

in the

and

et

"C.

G/C

5 ml

of

al.

Assay cell

filter). ACS-II

weighed.

buffer

(pH

centrifuged and

the

binding was

were final

as

crude

(1975)

using

(1974). was

The

The and

using with

the

filters subsequently

mix-

by x

of

binding

reaction

(3

the minor

method

(QNB)

terminated

harvester

by min

The

study

benzylate

20

pellets

conducted

Snyder

The

7.6)

for

recentrifuged.

conducted

automated

Whatman

containing

were discarded

Bennett

and

Tris-HCl

[3H]quinuclidinyl

Bradndel 7.6,

dissected

receptor

binding The

mM

homogenized

for

incubated using

a

[3H]ketanserin

(1979).

the

were

was

homogenates

then

[3H]prazosin

buffer,

to counting

cortex

vol.

used

et

Bremner

1)

frontal

supernatants

The

technique

tris-HCl

in-

added

of extraction

the

25

and

immediately

using

(Table

filtration cold

4 "C.

same

The

and

conducted

and

inositol

PT-10/35.

Battaglia

modifications.

tures

in

preparations.

methods

were

radioactivity.

stimulation

the

polytron

were

membrane

Slices

Assay

homogenized

the

suspended

was

percentage

in-

agonist.

decapitation,

tissue

at

the

the

samples

KH

and

supernatant

and

the

of

90 min

rinsed

stopped

the

and

ul

"C for

reaction of

et

Briefly,

250

37

LiCl.

TCA

from of

phospholipids.

radioactive

The

of

in

at

were

collected

was

cortical

of Lowry into

equi-

of Berridge

vere

mM

ul

ml

was

centrifuged,

in

7.5

containing

of

content

method

of

Receptor

means

protein

the

as

absence Radio

were

incorporation

expressed

1

3 vol.

total

LiCl

slices

750

removed

with

ml

the

phospholipids

incorporation

was

method

incubated mM

(TCA). and

phase

buffer,

modifications.

Reactions

with

columns

Eight for

homogenates

to

inositol

the

formate.

tissue

according

to

counted

into

acid min,

upper TCA

7.5

containing

homogenized

times

and

and

inositol-mono-phosphate

mM

ACS-II

washed

condition.

10

(KH)

the

minor

Labeled

buffer same

for

three

added

and

with

condition.

rpm

by washing

form)

8,

ul

were

trichloracetic

2500

by using

(1984)

they

the

Krebs-Hensleit

7.4).

assayed

al.

in KH

under

collected.

Samples

was et

oxygenation

65

"C (pH

[3H]myo-inositol

at

x

37

incubated,

centrifuged

solution

in a modified

at

Brown

2 uCi

same

cubated

tion

and

were

cubated

min

CO2

mono-phosphate

containing

under

60

02/5X

1983)

slices

buffer

for

95X

563

rapid

3ml

were

ice-

trans-

counted

s. Morlnobu et al.

564

Table

1

Displacers and Experimental Radioligands, Employed in the Receptor Binding

Receptor

prazosin

Displacer

Total

radioactivity

Rats

Data

by

Swimming were

height

5-HT (100 uM)

atropine (1 uM)

0.1 ml of each membrane prepara0.1 ml of each [3H]-ligands, tion and 0.8 ml of 50 mM Tris-HCl buffer. 0.1 ml of each [3H]ligand, 0.1 ml of each binding membrane 0.1 ml of each displacer and 0.7 ml 50 mM Trispreparation, HCl buffer.

binding:

Forced

L3HlQNB

Ketanserin

phentolamine (2 uM)

Non-specific:

for

L3Hl-

L3Hl-

ligand

M-Ach

5-HT2

ol-AD

t3Hl-

Conditions Assay

liquid

Test

forced

of water

scintillation

counter.

(FST)

to

(20

swim

"C)

for

15 min

(Porsolt

a vertical

et al

cylinder

containing.25

cm

1978).

Analysis

Significant using

differences

Mann-Whitney's

sidered

to

be

between

U-test.

significant

The

when

the

control

difference

a P value

and

FST

between

was

group

mean

smaller

were

values

than

determined

were

con-

0.05.

Results ] 3 HlIPl All

Accumulation agonists

cumulations tion

S-HT.

Changes

7510

were

respectively. and The

the

present

for

at

100

maximal

carbachol

study

manner

level The

EC50

in

submitted were the

[3H]IP,

stimulated

(Fig

1).

urn 5-HT,

188

NA and

f

13 X,

ac-

accumula-

noradrenaline of

513

carbachol

[3H]IPl

t3H]IPl

ImM

accumulations

were

5-HT,

control

to

f3H]IP1 the

denoted

as

FST.

The

accumulation protein group

not

Accumulations

forced the

incorporation

and

* 53 cpmimg

the

plateau

Agonists-Stimulated

control

basal

in

t3H]IPl f 38

were

and

induced

T and

0.3

uM,

988

t

14 uM

respectively.

which

ferences

in

uM,

used

concentration-dependent

noradrenaline

in

Rats time,

were

maximal

respectively.

246

the

a

the

carbachol,

98 Z, and

in

reached

10 mM by

which

of FST

swimming

group

did

submitted

test There

[3H]myo-inositol not

[3H]IPl to

FST

for

a

i 45

no

min

187

of

phospholipids

x

induced

by

difbetween

change

protein

f 21 I.

swimming

significant

significant cpm/mg

accumulation was

FST 15

were into

induce

6520

(control: x 10b3).

FST.

After

in

10m3,

the FST:

10 uM 5-HT

5-HT-stimulated

1200

WOO

--o--

800

Serotonin Noradrenaline

600

400

200

0

-6

-7

.B

-5 -4 -3 % Log [agonist (M)]

-2

.f

Fig

r3H]IPl accumulations in rat cerebral cortex 1. The agonist-stimulated slices. Data presented are X of the basal (unstimulated) values and the mean f S.E.M. from S-10 det3rminations for each group. Vertical bars represent S.E.H. The mean basal 6 H]IPl accumulation from al1 experiments was 6010 f 58 cpmlmg protein Y IO- . in the group FST was 130 f 6 X. which f3HlIPl accumulation nificantly lower than the value in the control group(Fig ZB). On the other band, [3N]IPl accumulation the control

group (Fig 2A). [3H]IP, accumulation

was likewise

uninfluenced

tive

reduction

serotonergic

of 5-HT-stimulated neuronal

['H]IP1

transduction

stress in the neuronal transduction

different

induced

by FST: 846 S 71 X (control);

111 K (FST) (Fig 2Cf. These findings indicate

of

E3KfIPl accumula-

tion in the group FST was 519 f 65 L, which was not significantly mM carbachol

sig-

induced by 100 ut4 noradrenaline

group was 477 f 51 "I Noradrenaline-stimuIated

from that in the control

was

by 1 839 f

that the PST induces a selec-

accomulatian,

implying

systes is most susceptible

that

the

to the acute

systems examined in this study.

Influence of FST on Neurotransmitter-Receptors It was examined whether the al-adrenoceptor,

S-HT2 and muscarfnfc

binding characteristics

were influenced

significant

both in the Bmsx and Kd values between

and

FST

differences

in

[3H]ketanserin

those

three

binding

the S-HT-induced

classes

characteristics

[3H)IPl accumulation

Hmax (fmol/mg protein) i 6.6; the corresponding

receptor

by the FST for 15 min. There were no

receptors. were

not

It

is

influenced

was attenuated

the control

noteworthy by FST

that whereas

by FST: the values

of

in the control and FST 15 were 116.3 f 9.7 and 104.5 values of Kd fnM) were 0.53 f 0.09 and 0.63 i 0.09,

566

S.Morinobuelai

Fig 2. The influence of the FST for 15 min on the agonist-stimulated [3H]IP accumulations in rat cerebral cortex slices. of the FST on NA for 15 min. A: Influence accumulation. Control: the group of rats not FST: the group of rats subgitted to FST (n = 8).B: Influence of the FST on 5-HT (100 uM)-stimulated [ H]IPl accumulation in Control (n = 8) and SST (n = 8) group. C: Influence of the FST on carbachol (1 qM)-stimulated [ H]IPl accumulation in Control (n = 7) and FST (n = 9) group. Data presented are Ve tical bars represent S.E.M. ** p < 0.01 vs. control levels. mean f S.E.M. The mean basal [4 H]IP ccumulation frgm all control experiments was 6520 f 45 cpm/mg protein x lb-?. The basal [ H]IPJ3 accumulation from all FST experiments was 7510 f 53 cpm/mg protein x 10 . respectively not affect

(Table 2). These results

the

affinity

density and

indicate that the FST for 15 min did of 5-HT2

receptors

in rat cerebral

cortex. Discussion Recent

pharmacological

hydrolysis tivation

of

phosphlipase

several C

Conn

release

types

(PLC)

1,4,5-trisphosphate including 1984,

and

neurochemical

studies

of phosphoinositol-4,5-bis-phosphate

cortex

and Sunders-Bush from

the

to

two

and

1984,

second

reticulum

that

activation

messengers,

the

by acof

inositol-

(DAG) in a variety of tissues,

1975,

Nishizuka

revealed

is catalyzed

the subsequent

putative

(Michell

endoplasmic

generated

into the cytoplasm has been shown

receptors,

(IP3) and diacylglycerol

the cerebral

tetrakisphosphate

of

generates

have

(PIP2)

Berridge 1984). and

1984.

IP3 has

Brown

et

al

been shown to

inositol-1.3,4,5-

from IP3 has been shown to increase Ca++ influx

(Steb et al 1983, Berridge

1984). DAG, on the other hand,

activate protein kinase C (PKC) (Nishizuka

1984, Nichols

567

Acutestress and agonist-stimulated PIhydrolysis

Table 2. Influe ce of FST for 15 'IIon [3Hlprazosin, [%]ketansarin and ]'H]QNB binding. Bmax (fmol/mg protein)

”

Kd (nM)

[3Hlprazosin Control FST

6 6

43.5 * 1.3 40.3 f 1.5

0.37 f 0.04 0.33 f 0.02

[3H]ketaserin Control FST

6 6

116.7 f 7.9 104.5 f 5.4

0.56 * 0.07 0.63 f 0.07

6 6

1250 f 225 1000 f 95

! 3HlQNB

Control FST

117 * 21 126 f 25

Values presented are mean f S.E.M. The value of Kd in QNB binding is pM. et al 1987). Therefore, responsible

phosphoinositide

for the receptor-mediated

It has been well known that certain neuronal

signal

transduction

has been proposed

to be

types of stress induce the changes in

which

is

Some investigators

neurotransmitters.

hydrolysis

neuronal signal transduction. mediated

by

several

have demonstrated

classes

of

that the release of

S-HT and acetylcholine, and the concentration of 3-methoxy-4NA. hydroxyphenyl ethyleneglycol in the stress situation such as immobilization stress

(Morgan et al 1975, Reinhard

et al 1984,

Farska

workers

(1982)

density

of 5-HTl,

et al

1988,

demonstrated whereas

for 15 min decreased

et al 1982, Tanaka

Imperato

et al

that the repeated Estevez

et al.

Segawa

and

his co-

FST for 5 min increased

(1984)

the density of muscarinic

et al 1983, Estevez

1991).

indicated

receptors

that

the

single FST

in the rat cerebral

cortex. Relationships

between the Stress and PI Hydrolysis

In the present study, the FST for 15 min induced significant S-HT-stimulated for

15

min

stimulated significant

[3HJIPl accumulation

induced

[3WP,

no

significant

accumulation.

changes

enhanced

FST

for

method

15 min to inject

Raskovsky

stimulated

NA-

for

and

15 min

carbacholinduced

of al-adrenoceptors,

and muscarinergic

of

the FST

transductions

no 5-

with are

Up to now there have been only a few studies

which have been focused to investigate and PI hydrolysis.

the

reduction While

these findings are not consistent

serotonergic

by the acute stress.

in

cortex,

the FST

characteristics

Apparently,

the view that adrenergic,

changes

Moreover,

in the binding

HT2 and M-Ach receptors.

in rat cerebral

the relationships

and Medina

PI metabolism

[3H]myo-inositol

(1989)

have

in rat cerebral

into cerebral

between the stress

demonstrated cortex

ventricles.

Their

that

the

using

the

findings

568

S. Morinobu elal.

suggested stress

that

the

situation

sociates

did

pocampal

not

the

FST

Since

Present more

findings by

muscarinic

central et

al

the

noradrenergic

those

in

while

the

previous

metabolism

and

experiments intracellular

and

HT

and

evoked

this the

acute

desensitization

Pieces

may

play

influence

signal

other

by

in al

the

elucidate

not the

may

with

mild

in

the

strength

immobilization

the

but

affinity, in

present

postsynaptic

stress

determined

not that

neurotransmitter

changes

of

events

and

the

(Reinhard

noteworthy

the

density on

previous

system

is

and

whereas

stress

the

It

influenced

the

altered,

that

changes

be

noradrenergic

serotonergic

1983).

receptor

and

have

induced

the

of

5-HT2

by

the

that

employed

may

the

be

human They

the

in

reason

may

be

release

platelets suggested

of PKC.

FST

acute

FST-induced

in

receptors.

activation

by

that

role

PI

investigations

has

certain

been

connection, in

caused

stress

the

by

due

of

5that

Attenuation to

the

of acute

endogenous

using

the

accumulating

the

FST was

on

5-HT

be

types

in

the

of

in

affective

of

the the

the phar-

hydrolysis

disorder.

The

serotonin-

and

present stress

to elucidate the

recent PI

noradrenaline-.

required

process

in

affect

receptor-mediated

studied

other

may

transduction

neuroleptics

pathogenesis

the

hydrolysis

neurotransmitter-agonists

receptor-mediated

demonstrated

accumulation

indicating

important

of

be

In this

carbachol-stimulated Further

on

the

transduction

studies. an

receptor-

cortex.

evidence

intracellular macological

re-examined

muscarinic

the

reported

et

postsynaptic

[3H]IPl caused

brain of

been

of

(1990)

may

5-HT-stimulated

rat

by

to

desensitization

desensitization

in the

hyp-

findings.

co-workers

an

rat

discrepancies

authors

consistent

influenced

changes

types

or

not

to

was

focused

out The

the as-

serotonergic

apparent

transduction

compared

are

(Tanaka

was

pre-

in

in his

Transduction

metabolism

it has

metabolic

carried

of controversial Kagaya

was

system

process.

studies,

as

results

characteristics

were

serotonergic

hand,

study

and

of

the

‘x1- and

Serotonergic

situation

in

hydrolysis Kusumi

decline

implicate

5-HT2,

and

that

These

other

PI

accumulation

or

PI hydrolysis,

serotonergic

induced

hand,

[3H]IPl

the

metabolism

the

acutely

in

other

rat,

Stress

stress

central

On

1982).

of

indicate

noradrenergic

stress

these

the

involved the

findings

in the

in the

the

On

significant

previous stress

transduction.

that

no

modulation

between

readily

report

the

hydrolysis

Relationships

FST.

S-HT-stimulated

the

of

induced PI

transduction the

suggesting

influence

mediated

by

change

slices,

transductions. in the

increased

caused

experiments. by

the

pathogenesis

the

use

role

of

of the

of affective

disorder.

Conclusion The

authors

tenuation

of

conclude the

that

the

5-HT-stimulated

FST

for

[3H]IPl

15

min

induces

accumulation

a in

significant the

rat

at-

cerebral

569

Acutestress and agonist-stimulated PIhydrolysls

cortex without affecting of

the

same

stimulated

the density and affinity

strength did not

induce any

of 5-HT2 receptor.

changes

on NA-

The FST

and carbachol-

[3H]IPl accumulation. References

ALLISON, J. H., BLISNER, M. E., HOLLAND, W. H., HIPPO, brain myo-inositol-l-phosphate W.R. (1976) Increased rats. Biochem. Biophys. Res. Commun. -71: 664.

P. P. and SHERMAN, in lithium-treated

AVISSAR, S., SCHREIBER, G., DANON, A. and BELMAKER, R.H. (1988) Lithium inin rat cortex. hibits adrenergic and cholinergic increase in GTP binding Nature 331: 440-442. BATTAGLIA. G., SHANNON, M. and TITELER. M. (1983) Modulation of brain S2 by lithium sodium and potassium chrolide. Life Sci. receptors serotonin -32: 2579-2601. and lysergic acBENNETT, J. P. and SNYDER, S. H. (1975) Serotonin diethylamide binding in rat brain membranes: Relationship to postsynaptic serotonin receptors. Molec. Pharmacol. -12: 373-389. BERRIDGE, M. J., DOWENS, C. P. and HANLEY. M. R. (1982) Lithium amplifies agonist-dependent phosphatidylinositol responses in brain and salivary glands. Biochem. J. 206: 587. BERRIDGE. M. J., DAWSON, R. M. C., DOWENS, C. P., HESLOP, J. P. and IRVINE, R. F. (1983) Changes in the levels of inositol phosphates after agonistdependent hydrolysis of membrane phosphoinositides. Biochem. J. 212: 473-482. BERRIDGE, M. J. (1984) Inositol trisphosphate messengers, Biochem. J. 220: 345-360.

and diacylglycerol

as a second

BROWN, E., KENDALL, D. A. and NAHORSKI. S. R. (1984) Inositol phospholipid hydrolysis in rat cerebral cortical slices: I. Receptor characterization. J. Neurochem. 42: 1379-1387. CONN, P. J. and SUNDERS-BUSH, E. (1984) Selective 5HT-2 antagonists inhibit serotonin stimulated phosphatidylinositol metabolism in cerebral cortex. Neuropharmacol. -23: 993-996. ESTEVES, E. E., JERUSALINSKY, D., MEDINA, J. H. and DE ROBERTIS. E. (1984) Cholinergic muscarinic receptors in rat cerebral cortex, basal ganglia and cerebellum undergo rapid and reversible changes after acute stress. Neuroscience -13: 1353-1357. FARSKA, I., KRULIK, K. and SLIVA. D. (1988) Effect of immobilization stress on tricyclic antidepressant binding and serotonin uptake in rat. Eur. J. Pharmacol. 149: 363-366. GREENGRASS, P. and BREMNEK, R. (1979) Binding characteristics 3H-prazosin rat brain a-adrenergic receptors. Eur. J. Pharmacol. -55:323-326.

to

IMPERATO. A., PUGLISI-ALLEGRA, S., CASOLINI, P. and ANGELUCCI, L. (1991)Changes in brain dopamine and acetylcholine release during and following stress are independent of the pituitary-adrenocortical axis. Brain Res. 538: 111-117. KAGAYA, A., MIKUNI, M., KUSUMI, I. and TAKAHASHI, K. (1990) Serotonininduced acute desensitization of serotonin2 receptors in human platelets via a mechanism involving protein kinase C. J. Pharmacol. Exp. Ther. -255: 305-311. KUSUMI, I., MIKUNI, M., KUKODA, Y. and TAKAHASHI, K. (1990) Subchronic administration of para-chlorophenylalanine enhances serotonin-stimulated phosphoinositide hydrolysis in rat hippoccampal slices. J. Neural Transm. 80:181-188. LOWRY, 0. H., ROSEBROUGH. N. J., FAKK, A. L. and RANDALL, R. J. (1951) Protein measurement with the folin phenol reagent. J. Biol. Chem. -193:

S. Mortnohu elaL

570

265-275. MICHELL, R. function.

phospholipids H. (1975) Inositol Biochem. Biophys. Acta. 415: 81-147.

MORGAN,

W.,

W.

RUDDEN.

lization stress on brain. Life Sci. u:

and

cell

surface

P. K. and PFEIL, K. A. (1975) Effect of immobiserotonin content and turnover in regions of the rat 143-150.

R. A., HAYCOCK, J. W., WANG, J. K. T. and GREENGARD, ester enhancement of neurotransmitter release from Phorbol synaptosomes. J. Neurochem. 48: 615-621.

NICHOLS,

NISHIZUKA,

Y.

(1984)

implications.

receptor

The

molecular

heterogeneity

of

protein

kinase

P. (1987) rat brain C and its

Nature (Lond.) 308: 693-698.

treatment OZAWA, H. and RASENICK. M. M. (1990) Chronic electroconvulsive augments coupling the GTP-binding protein Gs to the catalytic moiety of cyclase in a manner similar to that seen with chronic antidepres adenyl sants drugs. J. Neurochem. 56: 330-338. PORSOLT,

R,

D.,

ANTON,

G..

despair in rats: A new model J. Pharmacol. -47: 379-391. RASKOVSKY, inositides

S. and

BLAVET. N. sensitive

MEDINA, J. (1989)

breakdown

after

an

acute

and JARFER,

M.

to antidepressants

(1978)

Behavioral Eur.

treatments.

In vivo changes in brain phosphostress. J. Neurochem. 52: 9165.

Acceleration by stress REINHARD. j. F., BANNON. M. J. and ROTH, R. H. (1982) and metabolism in prefrontal cortex: Antagonism by of dopamine synthesis Naunyn-Schmiedeberg's Arch. -318: 374-377. diazepam. M. (1982) New vista in depression. pp 3SEGAWA. T., MIZUTA, T. and UEHARA.

10, Pergamon Press, Oxford. (1983) Release of ST~,B2+H;;o,'","","d,m~.,o~~~n~~~~~DG~~tr~ce~iu~~~ ",",",",","* iT; pancreatic acinar cells by inositol-1,4,5- trisphosphate. Nature 306: 3-10. TANAKA, M., KOHNO, Y., NAKAGAWA, R., HISHIKAWA, T., TSUDA, A. and NAGASAKI, N. (1983) Immobilization stress increases serotonin turnover in the extended brain regions in the rat. The Kurume Med. J. 0: 35-43.

cholinergic YAMAMURA, H. I. and SNYDER, S. H. (1974) Muscarinic rat brain. Proc. Nat. Acad. Sci. USA fl: 1725-1729.

binding in

YAMAOKA, K., NANBA, T. and NOMURA, S. (1988) Direct influence of antidepressants on GTP binding protein of adenylate cyclase in cell membranes of the cerebral cortex of rats. J. Neural Transm. 2: 165-175. Inquiries and reprint requests should be addressed DR. SHIGERU MORINOBU Department of Neuro-Psychiatry Yamagata University School of Medicine Iida-nishi 2-2-2, Yamagata 990-23 JAPAN

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