BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

Vol. 180, No. 3, 1991

Pages ] 5 ] 8 - ] 5 2 6

November 14, 1991

THE T H A P S I G A R G I N - S E N S I T I V E INTRACELLULAR C a 2+ POOL I S MORE IMPORTANT I N PLASMA MEMBRANE C a 2÷ ENTRY THAN THE I P 3 - S E N S I T I V E INTRACELLULAR C a 2÷ POOL I N NEURONAL CELL L I N E S

Haruo

Takemura,

Hideyo

Keiji

Departments

Ohshika,

Oguma* a n d

Yokosawa*,

Thastrup**

of Pharmacology and *Microbiology, Sapporo College, S.1, W.17, Sapporo 060, Japan **ZymoGenetics, Inc., Seattle,

Received

Ole

Noriko

October

7,

4225 Roosevelt WA 9 8 1 0 5

Medical

Way NE

1991

In NG108-15 cells, bradykinin (BK) a n d t h a p s i g a r g i n (TG) c a u s e d transient increases in a cytosolic free Ca 2+ c o n c e n t r a t i o n ([Ca2÷]i), a f t e r w h i c h [Ca2+]i e l e v a t e d b y TG o n l y d e c l i n e d to a higher, sustained level than anunstimulated level. I n PC12 c e l l s , carbachol (CCh) e v o k e d a transient increase in [Ca2÷]i followed by a sustained rise of [Ca2÷]i, whereas [Ca2÷]i e l e v a t e d b y TG a l m o s t m a i n t a i n e d its higher level. In the absence of extracellular Ca 2÷, t h e s u s t a i n e d elevation of [Caa÷]i i n d u c e d b y e a c h d r u g we u s e d w a s a b o l i s h e d . In addition, the rise in [Ca2+]i s t i m u l a t e d b y TG w a s l e s s a f f e c t e d after CCh o r BK, w h e r e a s CCh o r BK c a u s e d no increase in [Ca2÷]i after TG. TG n e i t h e r increased cellular inositol phosphates nor modified the inositol phosphates formation stimulated b y CCh o r BK. We c o n c l u d e that TG m ay r e l e a s e Ca 2÷ f r o m b o t h I P 3 - s e n s i t i v e and -insensitive intracellular pools and that some kinds of signalling to link the intracellular Ca 2÷ p o o l s a n d C a 2+ e n t r y

seem

to

exist

Intracellular functions,

C a 2÷

and be

an

increase to

can

entry

Ca 2+ f r o m

relationship is

less

capacitative the

entry 12) into

Ca 2÷ e n t r y

depletion

plasma

of

has

and

is

aortic

smooth

intracellular

signalling neuronal

to

link

muscle

fluid and

free

into

been

cells

cells It

types (13)

is

acinar

thus

using

by Putney

1518

called

(3,4),

(5-7).

Ca 2÷ r e f i l l i n g that

the

of neurons

Ca 2+ s t o r e

possible

and

However,

of non-excitable

Ca 2+ p o o l

cells.

stores

a model,

cells

neuronal

concentration

Ca 2÷ p o o l s

reported

proposed

parotid

Ca 2+

(1,2).

intracellular rat

numerous

intracellular

intracellular

intracellular

0006-291X/91 $1.50 Copyright © 1991 by Academic Press, Inc. All rights of reproduction in any form reserved.

for

Ca 2÷ f r o m

in a variety

Ca 2÷ p o o l s . the

signal

originally

in

® 1991 Academic Press, Inc.

cytosolic of

IP3-sensitive

confirmed

a

recently

and

m e m b r a n e Ca 2+ e n t r y model

in

release

Ca 2÷ e n t r y It

cells.

as

extracellular

between

clarified.

neuronal

serves

due

([Ca2÷]i) of

in

that

activates This

Ca 2÷

cells

(8-

process

some k i n d s

a n d Ca 2÷ e n t r y

a

exist

of in

Vol. 180, No. 3, 1991

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

Thapsigargin selective to

inhibitor

cause

of

of cellular

to

activate this

entry

We h a v e

shown

that

between

Ca 2+ e n t r y

(6).

the

In

of neuronal 15

cells

sensitive entry

of

is

and

rat

and

not

lines,

ester

several

of

tool

the

neuroblastoma

pheochromoeytoma Ca 2÷ p o o l

PC12 may

IP3-sensitive

MATERIALS

AND

cells

in

the

parotid

been

of

x rat

glioma and

more

shown

also

been

(6,17-21); (22).

relationship cells

TG o n t w o hybrid

found

important

intracellular

a

without

acinar

actions

a

and

a Ca 2÷ i o n o p h o r e

cells,

have

has

TG h a s

studying

Ca 2÷ p o o l

we e x a m i n e d

Ca 2÷ t h a n

as

as

promoter

(14,15)

Ca 2÷ i n t o

an action

intracellular

types

(6,16-18).

external to

tumor

(14,15),

cell

phosphates

due

mouse

type

Ca2÷-ATPase

in

a useful

study,

intracellular external

entry

TG i s

present cell

[Ca2÷]i inositol

an

however,

a nonphorbol

of microsomal

elevation

production found

(TG),

kinds NG108-

that role

TGin

Ca 2÷ p o o l .

METHODS

Materials. Fura-2/AM was obtained from Molecular Probes; Bradykinin (BK) a n d c a r b a m y l c h o l i n e (CCh) from Sigma; m-conotoxin GVIA from Bachem; myo-[2-3H]-inositol ( 6 3 3 G B q / m m o l ) a n d [ 3 H ] i n o s i t o l phosphate mixture (37 GBq/mmol) from Amersham International; Dowex column and anion exchange resin AG 1 - X 8 ( 2 0 0 - 4 0 0 mesh, formate form) from Bio-Rad. Nimodipine was a gift f r o m B a y e r AG. Cell Culture. Mouse neuroblastoma x rat glioma hybrid NG10815 c e l l s , donated b y D r . Y. N o m u r a ( F a c u l t y of Pharmaceutical Science, Hokkaido University), were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with i00 DM hypoxanthine, 0.4 DM aminopterin, 16 D M t h y m i d i n e a n d 10% fetal calf s e r u m (FCS), as d e s c r i b e d p r e v i o u s l y (23). Rat p h e o c h r o m o e y t o m a PC12 ceils, p r o v i d e d by J a p a n e s e C a n c e r R e s e a r c h R e s o u r c e B a n k - C e l l , w e r e c u l t u r e d in RPMI 1640 m e d i u m supplemented with 10% h o r s e s e r u m and 5% FCS in a h u m i d i f i e d a t m o s p h e r e of 92% 02 a n d 8% CO 2 at 37°C in the c o l l a g e n coated culture dishes. [Ca2÷]i Measurement. Both types of cells in culture dishes (150 mm i n d i a m e t e r ) passed 3 days were preincubated with 2 pM f u r a - 2 / A M in Krebs-Ringer-Hepes solution (KRH) f o r 30 m i n a t r o o m t e m p e r a t u r e under oxygenation. KRH c o n s i s t e d of the following: N a C 1 , 1 2 0 mM; K C 1 , 5.4mM; MgSO4, 0 . 8 mM; C a C 1 2 , 1 . 0 mM; g l u c o s e , 1 1 . 1 mM; H e p e s , 20 mM; 0.2% bovine serum albumin (pH 7 . 4 ) . After load with fura-2, NG10815 a n d P C 1 2 c e l l s were detached from dishes by gentle pipetting and trypsin-EDTA solution, respectively, and were washed twice with fresh KRH b y c e n t r i f u g a t i o n and then resuspended with 2 ml of KRH i n cuvette. The fluorescence of fura-2-1oaded cells was measured with Hitachi spectrophotometer (650-10S) at an excitation waveiength of 340 nm a n d a n e m i s s i o n wavelength o f 5 0 0 rim. To m i n i m i z e leakage of fura2 from cells, temperature was kept at 32°C during fluorescent measurement (24). Maximum and minimum fluorescence was obtained by 0.01% triton-X and 5 mM EGTA w i t h Trizma Base (25). [Ca2÷]i was calculated by Grynkiewicz et al. (26).

passed

Measurement o n t o 35

of Inositol mm p l a s t i c

Phosphates. NG108-15 tissue culture dishes 1519

and PC12 cells were and were grown in

V o l . 180, N o . 3, 1991

BIOCHEMICAL A N D BIOPHYSICAL RESEARCH COMMUNICATIONS

monolayors for 1 day, followed b y 2 d a y s i n DMEM c o n t a i n i n g 5 BCi/ml myo-[2-SH]-inositol and in supplemented RPMI 1 6 4 0 c o n t a i n i n g 10 ~ C i / m l myo-[2-3H]-inositol, r e s p e c t i v e l y . Prelabelled dishes were washed t w i c e w i t h KRH a n d p r e i n c u b a t e d w i t h KRH c o n t a i n i n g 10 mM L i C 1 f o r 10 min at 37°C, and then drug was added. The mixture was further incubated f o r 30 s . T h e r e a c t i o n was then terminated b y 1 ml o f 20% trichloroacetic acid. The preparations w e r e k e p t o n i c e f o r 30 m i n a n d were centrifuged. The supernatant was washed three times with watersaturated ether to remove trichloroacetic acid from the solution. The resultant solutions were applied t o D o w e x AG l - X 8 c o l u m n a c c o r d i n g to Downes et al. (27). Elution profiles of inositol monophosphate (IP1), inositol bisphosphate (IP2) and inositol trisphosphate ( I P 3) f r o m t h e column were checked by standard mixture o f I P 1, I P 2 a n d I P 3. A f t e r elution with two times o f 10 m l w a t e r a n d o n e t i m e o f 10 ml o f 5 mM borax/60 mM s o d i u m f o r m a t e , IP1, IP z and IP 3 were eluted sequentially by an ammonium formate gradient in 0.1 H formic acid as follows: five t i m e s e a c h w i t h 2 ml o f 0 . 2 M f o r I P 1, t h r e e t i m e s e a c h w i t h 2 ml o f 0 . 4 M f o r I P 2, a n d f i v e t i m e s e a c h w i t h 2 ml o f 0 . 7 5 M f o r I P s. T h e radioactivity of each fraction was measured.

RESULTS The effects are

shown in

of

extracellular

of

Fig.

1 DH TG o n

1 and Fig. Ca 2+,

2,

[Ca2+]i i n N G 1 0 8 - 1 5 respectively.

1 pM BK c a u s e d

a

cells

In the

transient

a n d PC12 c e l l s presence

increase

of in

1 mM

[Ca2+]i

180 - 250--

]oo--

3 mM EGTA

150--

50-80--

t BK

r ~~

\

"~

20--

I 3 mM

TG

I

EGTA BK 70--

160~

I00~ 6o~

TG

~

t TG

/

5O-- "

t BK

3o_

~

~

1 TG

2 min

~

t BK

F i g . 1. E f f e c t s o f 1 llM b r a d y k i n i n (BK) and 1 pM t h a p s i g a r g i n (TG) on [CaZ÷]i i n t h e p r e s e n c e o f 1 mM Ca 2÷ ( l e f t t r a c e s ) or the absence of extracellular Ca 2÷ ( r i g h t t r a c e s ) i n NG108-15 c e l l s . The f u r a - 2 l o a d e d c e l l s w e r e d e t a c h e d by g e n t l y p i p e t t i n g from c u l t u r e d i s h as d e s c r i b e d i n MATERIALS AND METHODS, w a s h e d t w i c e , and t h e n r e s u s p e n d e d in cuvette. 1520

V o l . 180, No. 3, 1 991

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

300 - ~2o-200

-

3 mM

-

,o_

60--

z=

20--

~

~, CCh TG

TG CCh

CCh ~2o--

200

-

I00

-

3 mM

7All ,o_-, \

-

-

50--

?

m,,,-

t

TG

TG

2

rain

Fig. 2. Effects o f 1 0 0 pM c a r b a c h o l (CCh) a n d 1 BM t h a p s i g a r g i n (TG) o n [Ca2+]i i n t h e p r e s e n c e o f 1 mM Ca 2÷ ( l e f t traces) or the absence of extracellular Ca 2÷ ( r i g h t traces) i n PC12 c e l l s . The fura-2 loaded cells were detached by trypsin-EDTA medium from collagen-coated culture dish as described i n MATERIALS AND METHODS, w a s h e d t w i c e , and then resuspended in cuvette.

after

which

it

which

declined

(Fig.

1).

in

other

which

in

a

sustained

both

C a 2÷

responsible cells,

PC12

levels

of

and

1

lxM

nimodipine [Ca2÷]i

and

the

L-type

and induced

the

L-type

and

influx

TG

into

C a 2÷ or by

Fig.

in

both

TG

in

C a 2÷ c h a n n e l

did both

not cells 1521

N-type

(data

by

types

not

than the

that

TG

medium of

voltage-

channels, and TG

that of

blockers,

the

types

(28)

3 shows

Moreover, alter

suggest

C a 2÷

induced

not.

[Ca2+]i

maintained

extracellular two

NG108-15

influx

cells

increase

of

almost

from

[CaZ+]i

NG108-15

transient

results

Because

respectively.

~-conotoxin by

These

in

level

which

C a 2÷ e n t r y

N-type

~-conotoxin,

2).

a

sustained

cells.

C a 2÷

induced

caused

[Ca2+]i

in

whether

and

higher

TG i n c r e a s e d

one

PC12

C a 2÷ c h a n n e l s

[Ca2÷]i by

the

(Fig.

channels,

voltage-operated

affected

to

whereas

resting

pM C C h

increased

cells

examined

level, than

100

increase

for

we

hand,

TG

NG108-15

operated

resting level

declined and

level

causes

to

higher

the

level,

high

into

to

On

[Ca2+]i

resting

declined

are

PC12 is

(29)

through

the

sustained

cells

were

not

1 lxM n i m o d i p i n e pretreatment

sustained shown).

levels These

with of data

V o l . 180, No. 3, 1991

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

200--

150--

~

iTM

90~

A

==

=-CTX TG

Nim

~3 250--

I

150-~-CIX

60 - -

t

2 min

TG

Fig. 3. Effects of 1 ~M nimodipine (Nim) and 1 BM m-conotoxin (mCTX) on the sustained increase in [Ca2+]i induced by 1 pM thapsigargin (TG) in NGI08-15 (top trace) and PCI2 (bottom trace) cells.

i n d i c a t e t h a t TG i s u n l i k e l y t o i n c r e a s e Ca2+ i n f l u x t h r o u g h v o l t a g e o p e r a t e d Ca2+ c h a n n e l s i n n e u r o n a l c e l l In the caused a

absence of e x t r a c e l l u l a r

transient

increase

l e v e l ( F i g s . 1 and 2 ) , Ca2+ from i n t r a c e l l u l a r and

CCh i n

transient

NG108-15

In c o n t r a s t ,

of

Ca2+, BK and CCh as w e l l as TG

[Ca2+]i which d e c l i n e d t o

a

resting

s u g g e s t i n g t h a t a l l o f a g o n i s t s we used r e l e a s e stores. cells

no i n c r e a s e i n

The s u b s e q u e n t a d d i t i o n of TG a f t e r BK

and

i n c r e a s e i n [Ca2+]i,

of BK o r CCK a f t e r Fig.

in

lines.

PC12 c e l l s ,

respectively,

caused

a

c o m p a r a b l e t o t h a t i n d u c e d by TG a l o n e .

[Ca2+]i i n d u c e d by t h e s u b s e q u e n t a d d i t i o n

TG was o b s e r v e d .

4 shows d o s e - r e s p o n s e c u r v e s o f peak and s u s t a i n e d l e v e l s

[Ca2+]i f o r

TG i n

NG108-15 c e l l s ,

normal

medium

i n NG108-15

w i t h maximal dose o f b e i n g 100 nM. In c o n t r a s t , i n c r e a s e in

and

TG d o s e - d e p e n d e n t l y i n c r e a s e d peak

[Ca2+]i i n d u c e d by TG d i d n o t

PC12 c e l l s . l e v e l of

In

[Ca2+]i ,

t h e l e v e l of s u s t a i n e d

change i n a d o s e - d e p e n d e n t

manner. ECs0 of t h e peak l e v e l o f [Ca2+]i f o r TG was 6 . 7 ± 0 . 8 nM (n=3). On t h e o t h e r hand, b o t h peak and s u s t a i n e d l e v e l s of [Ca2+]i were d o s e d e p e n d e n t l y i n c r e a s e d by TG, w i t h maximal dose o f b e i n g i00 nM i n PC12 ceils.

ECs0 v a l u e s peak and

s u s t a i n e d l e v e l s of

were 8 . 4 ± 1 . 9 nM and 7 . 1 ± 1 . 8 nM (n=3), E f f e c t s o f TG on i n o s i t o l PC12 c e l l s

were

examined.

As

[Ca2+]i i n d u c e d by TG

respectively.

p h o s p h a t e s p r o d u c t i o n i n NG108-15 and shown 1522

in

Table

1,

TG a l o n e

did

not

Vol. 180, No. 3, 1991

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

200,

200

~-

c

A

Peak

o--o

¢

o--o

150-

r~ +

100.

.E

T

Peak

o" ~

o - - - o Sustained

150

B

o .=

100

g :

c

~/

50-

i/I z

0

50

.

I~..~ ......... I ......

~. . . . . . . . . . . . . . .

I

I

I

I

I

I

I

I

1

10

100

1000

1

10

100

1000

Thapsigargin

(nM)

Fig. 4. Dose-response [Ca2÷]± to thapsigargin [CaZ÷]i was subtracted expressed as a net different experiments.

increase of

z

cellular

cells.

Nor

stimulated

Thapsigargin

relationships of peak in NG108-15 (A) and from thapsigargin-induced change. Each point is

inositol

modified

by

BK

phosphates TG t h e

and

( I P 1,

inositol

CCh

in

and sustained levels of PC12 (B) cells. Basal [Ca2*]i which was the mean±SEM in three

IP 2 and

phosphates

NG108-15

(nM)

I P 3)

in

(IPz,

cells

both

types

IP 2 and

and

PC12

been

reported

IP3)

cells,

respectively.

DISCUSSION The

microsomal

increase types of

[Ca2+]i of

cells

inositol

Table

I.

Ca2÷-ATPase

followed (6,17-21).

phosphates

Effects

of

by

a

This

thapsigargin

IP 1

sustained occurs

(6,17,18).

on

NG108-15

Treatment

inhibitor

IP 2

TG

has

entry

of

without A

inositol

C a 2÷ i n

concomitant

sustained

in N G I 0 8 - 1 5

cells

PC12

IP 3

variety

production

elevation

phosphates

a

to

of

[Ca2+]i

and PC12

cells

cells

IP 1

IP 2

IP 3

Control

3269±205

687±28

824±144

3077±460

944±78

928±118

1 BM TG

3137±323

624±127

761±70

3197±362

963+21

969±69

1 ~M BK

5098±622

1871±396

2017±410

-

-

-

TG + BK

5649±695

2296±371

2179±353

-

-

-

100 DM CCh

-

-

-

5728±551

2361±128

1837±125

TG + CCh

-

-

-

6200±240

2315±224

1859±55

C e i l s w e r e t r e a t e d w i t h d r u g s for 30 s in the p r e s e n c e of i0 m M LiCI. Inositol p h o s p h a t e s w e r e s e p a r a t e d b y D o w e x c o l u m n a n d are s h o w n as d . p . m . / w e l l . T h e r e s u l t s are e x p r e s s e d as m e a n ± S E M of t r i p l i c a t e e x p e r i m e n t s f r o m a b a t c h of c u l t u r e .

1523

Vol. 180, No. 3, 1991

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

i n d u c e d by T G w a s not pituitary

cells

consistent In cells

drug

(19)

and

induced

TG

did

with

at

least

the

and

of

intracellular

sensitive adrenal

chromaffin

of

We

do

insensitive Koshiyama

not

mobilization A

types pools a

revised cells

(5,8-13) link

was higher Ca 2+ pool rather

the

(6-7,18).

T G but n o t

model,

quite IP scells

caffeine-

(17)

and

bovine

supported inhibit

PC12

by

cells

that

the

a release (data

not

and

IP s-

instead,

that T G acts

speculate

TG-

there m a y

and

GTP-sensitive;

originally

on an

to IP s or

there

exist

role in Ca 2+

process

Ca 2+ e n t r y

results and

one.

role

However,

1524

and

s u g g e s t that there membrane cell

increase

Thus,

In

in [Ca2+]i. by T G

TG-sensitive

on a c a p a c i t a t i v e sustained

Ca 2+

lines.

in [Ca2+]i i n d u c e d

cells.

the

(3)

different

intracellular

plasma

in n e u r o n a l

increase in P C 1 2

in m a n y into

BK caused a sustained

important

proposed

supported

Ca 2+ p o o l s

induced by CCh

IPs-sensitive

be that

is not s e n s i t i v e

The present

of s u s t a i n e d

s e e m s to h a v e a n

than

may

h a v e an i m p o r t a n t

Ca 2+ r e f i l l i n g

a capaeitative

t h a n that

is

reported

to

has b e e n

intracellular

level

size of

is

cells.

using

and TG

cells,

tempting

Ca 2+ e n t r y

by

between

Furthermore,

is

the

TG-sensitive

also

recently

GHIC 1

or

that

is

Ca 2+ pool w h i c h

(4) by P u t n e y ,

entry and support NGI08-15

evidence

have

of w h i c h

in N G I 0 8 - 1 5

d i d not

cells

Ca 2+ p o o l s w h i c h

in n e u r o n a l

eapacitative

of

(31)

It

intracellular

recently

NGI08-15 an

GH4C z rat

(33). H o w e v e r ,

with caffeine

drug being

one

TG-sensitive in

[Ca2+]i

Ca 2÷,

Ca 2+ pool

cells

between

C a ~+ pool

in

that T G r e l e a s e s Ca 2+

and that

assumption

from

increase

Ca 2+ p o o l s ,

cells.

intracellular

in GH4C x cells.

suggest

the

IPs-producible

IPs-reproducible

like

have

and T a s h j i a n

multiple

is

TG

an

C a 2+ pools,

intracellular

ATP-dependent GTPyS

by

of

is G T P - s e n s i t i v e

This

TG-sensitive

In contrast,

It has b e e n r e p o r t e d

in PC12

that p r e t r e a t m e n t

Ca 2+ i n d u c e d

shown).

(34)

are

chromaffin

permeahilized

lines

one.

Ca 2÷ pool

"cross-talk"

intracellular

observation

in

intracellular

of I P 3 - s e n s i t i v e

apparent

in GH~C z

cells

extracellular

intracellular

(32) a n d is c a f f e i n e - s e n s i t i v e no

of

cell

and

addition

reported

IP3-insensitive

insensitive

IP 3-

of T G a f t e r

absence

in n e u r o n a l

that

PC12

adrenal

same.

while

(31). T h e s e o b s e r v a t i o n s

larger than

be

(30),

[Ca2+]i,

findings

pool,

and

bovine

subsequent

addition

the

two k i n d s

IP3-sensitive sensitive

the

(6,21),

to be a p p a r e n t l y

increase

in

NGI08-15

microsomes

seem

subsequent

p i t u i t a r y cells from

not

using

cells

that

affected

consistent

data

brain

show

by L - t y p e CaZ+-channel b l o c k e r

findings.

acinar

rat

b y the

less

Our

above

C a 2÷ p o o l s

results

after

was

the

parotid

intracellular present

(18).

with

rat

inhibited

Ca 2÷ e n t r y

increase

in

Vol. 180, No. 3, 1991

[Ca2÷]i

induced

NG108-15 [Ca2÷]i

different

is

In

in

neuroblastoma

and plasma

in

[Ca2÷]i

Ca 2+

and

plasma

types

cells.

Ca 2+ p o o l

and

Further

intracellular membrane

by

cells

is

needed

Ca 2+ p o o l s

that

and might

is

and

to

elevation link

Ca 2÷

entry

in

of

between the

between

a of

between may

be tighter

nature

clarify link

not

TG c a u s e d

a

different

a

but

sustained

why t h e

Ca 2÷ e n t r y

cells

Nl15-401L,

membrane

However,

study

no

PC12

suggested

of neuronal

NG108-15

line

followed is

pools

in

cell

it

unclear.

TG-sensitive

dose-dependent

Therefore,

between

than

intracellular cells

TG w a s

increase (16).

intracellular

cells

by

cells.

transient

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

be

i n PC12

linkage

of

types

of

natures such

of

pools

Ca 2+ e n t r y .

REFERENCES

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.

Blaustein, M.P. (1988) Trend. Neurosci. 11, 438-443. Tsien, R.W. a n d T s i e n , R.Y. (1990) Annu. Rev. Cell Biol. 6, 7 1 5 760. Putney, J.W.,Jr. ( 1 9 8 6 ) C e l l C a l c i u m 7, 1 - 1 2 . Putney, J.W.,Jr. (1990) Cell Calcium 11, 611-624. T a k e m u r a , H. a n d P u t n e y , J.W.,Jr. (1989) Biochem. J. 258, 409412. Takemura, H., Hughes, A.R., Thastrup, O. a n d P u t n e y , J.W.,Jr. (1989) J. Biol. Chem. 2 6 4 , 1 2 2 6 6 - 1 2 2 7 1 . Putney, J.W.,Jr., Takemura, H., Hughes, A.R., Horstman, D.A. and Thastrup, 0 . ( 1 9 9 0 ) FASEB J . 3 , 1 8 9 9 - 1 9 0 5 . Chow, S . C . a n d J o n d a l , M. ( 1 9 9 0 ) C e l l C a l c i u m 1 1 , 6 4 1 - 6 4 6 . Jacob, R. ( 1 9 9 0 ) J . P h y s i o l . 421, 55-77. Kwan, C . Y . , T a k e m u r a , H . , O b i e , J . F . , Thastrup, 0. and Putney, J.W.,Jr. ( 1 9 9 0 ) Am. J . P h y s i o l . 258, C1006-C1015. Montero, M., Alvarez, J. Garcia-Saneho, J. (1990) Biochem. J. 271, 535-540. A1varez, J., M o n t e r o , M. a n d G a r c i a - S a n c h o , J. (1991) Biochem. J. 274, 193-197. Missiaen, L., Declerck, I., Droogmans, G., Plessers, L., De Smedt, H., Raeymaekers, L. a n d C a s t e e l s , R. ( 1 9 9 0 ) J . P h y s i o l . 427, 171-186. Thastrup, O. ( 1 9 9 0 ) A g e n t s a n d A c t i o n s 29, 8-15. Thastrup, 0., Cullen, P.J., Drobak, B.K., Hanely, M.R. and Dawson, A.P. (1990) Proc. Natl. A c a d . S c i . USA 8 7 , 2 4 6 6 - 2 4 7 0 . Jackson, T.R., Patterson, S.I., Thastrup, 0. and Hanley, M.R. (1988) Biochem. J. 253, 81-86. Law, G . J . , P a t c h e r , J.A., Thastrup, 0 . , H a n l e y , M.R. a n d D a n n i e s , P.S. (1990) Biochem. J. 267, 359-364. Gouy,H., Cefai, D., Christensen, S . B . , D e b r e , P . a n d B i s m u t h , G. (1990) Eur. J. Immunol. 20, 2269-2275. Cheek, T.R. and Thastrup, O. ( 1 9 8 9 ) C e l l C a l c i u m 1 0 , 2 1 3 - 2 2 1 . Foder, B., Scharff, 0. and Thastrup, 0. (1989) Cell Calcium 10, 477-490. Foskett, J.K., R o i f m a n , C.M. a n d W o n g , D. ( 1 9 9 1 ) J . B i o l . Chem. 266, 2778-2782. Thastrup, O., Dawson, A.P., Scharff, 0., Foder, B., Cullen, P.J., Drobak, B.K., Bjerrum, P.J., Christensen, S . B . a n d H a n l e y , M.R. (1989) Agents and Actions 27, 17-23. Yokosawa, N., Kurokawa, Y., Tsuzuki, K., Syuto, B., Fujii, N., K i m u r a , K. a n d O g u m a , K. ( 1 9 8 9 ) I n f e c t . Immun. 57, 272-277. 1525

Vol. 180, No. 3, 1991

24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34.

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS

Malgaroli, A., Milani, D., Meldolesi, J . a n d P o z z a n , T. ( 1 9 8 7 ) J. Cell Biol. 105, 2145-2155. H u g h e s , A . R . , T a k e m u r a , H. P u t n e y , J . W . , J r . ( 1 9 8 8 ) J . B i o l . Chem. 263, 10314-10319. G r y n k i e w i c z , G . , P o e n i e , M. a n d T s i e n , R . Y . ( 1 9 8 5 ) J . B i o l . Chem. 260, 3440-3450. Downes, C.P., Hawkins, P.T. and Irvine, R.F. (1986) Biochem. J. 238, 501-506 Docherty, R.J. (1988) J. Physiol. 398, 33-47. Plummet, M.R., Logothertis, D . E . a n d H e s s , P. ( 1 9 8 8 ) N e u r o n 2 , 1453-1463. Verma,A., Hirsch, D.J., Hanley, M.R., Thastrup, O., Christensen, S . B . a n d S n y d e r , S . H . ( 1 9 9 0 ) B i o c h e m . B i o p h y s . R e s . Commun. 1 7 2 , 811-816. K o s h i y a m a , H. a n d T a s h j i a n , A.H.,Jr. (1991) Biochem. Biophys. R e s . Commun. 1 7 7 , 5 5 1 - 5 5 8 . C h u e h , S . - H . , L i u , J . - A . a n d K a o , L . - S . ( 1 9 9 0 ) J . N e u r o c h e m . 55, 1281-1286. Reber, B.F.X. and Reuter, H. ( 1 9 9 1 ) J . P h y s i o l . 435, 145-162. R o b i n s o n , I . M . a n d B u r g o y n e , R . D . ( 1 9 9 1 ) J . N e u r o c h e m . 56, 1 5 8 7 1593.

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