The ACTH- and GR-immunoreactivities in the brain after adrenalectomy

S239

507

LOCALIZATION OF CALBINDIN AND CALRETINIK bZ=\GNOCELLULAR

SEIJI

RIIY_4T=\. TOSHIKiZU

Dept.

of Appl.

Member

Biol.. Kyoto

of the EF-hand

modulate

I
Technol..

Matsugasaki.

family of Ca’ binding

intracellular

proteins

free Ca’ concentration.

that calbindin

and calretinin

hypothalamic

magnocellular

neurons. Quantitatil-e

for calbindin

and calretinin

dehydration

change of calbindin

immunoreacti\

including

606-8585.

calbindin

light and electron

anal!.ses re\ealed

it!. respectively

Japan

and calretinin.

microscopic

onI\

but also in nerve terminals

ot’the

neurons uere positive

Utstern

analyis

but not in the hypothalamic

neurons. and is necessar!

to buffer changes

shoMed

re\ealed

calbindin

that chronic

nucleus. although an>

was not seen. These results provide e\ idences that CaBP expression

both greater and more diverse than vasopressin

to has

25% of AVP neurons

immunoreacti\ity.

in the posterior pituitar!.

ha1.e the abilit!

immunohistochemistr!

that &lo o and 52% of os)-to&

Ho\\e\er.

devoid of calretinin

the amount ofcalretinin contents

(CaBPs).

Kpoto

are present not onI> in soma and dendrites

and they Lvere virtualI\

increased

Sakyo-ku,

The present

demonstrated

immunoreacti\,it>.

IN RAT HYPOTHALAMIC

NEURONS

in oqtocin

neurons

is

in intracellular Ca’- of soma.

dendrites and terminals. LOW-MOLECULAR-WEIGHT MAP2 IN THE HYPOTHALAMO-NEUROHYPOHYSIAL SYSTEM AND ITS FUNCTIONAL SIGNIFICANCE FOR STRUCTURAL PLASTICITY

508

WATARU MATSUNAGA

SEIJI MIYATA, TOSHIKAZU IUYOHARA

Dept. of Appl, Biol, Kyoto Instit. of Technol., Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan Microtubule-associated protein2 (MAP2) is the most abundant MAP in the central nervous system and is responsible for morphogenesis and maintenance of the nervous system. MAP2 is classified into two groups with molecular size; Highmolecular-weight (HMW, M.W.-230 kDa) MAP2 and Low-molecular-weight (LMW, M.W.-70 kDa). LMW-M@2 is immature variant of MAP2, and is expressed in embryonic and early postnatal brain but is not expressed in adult brain. In these experiments, we used immunostaining and Western blotting for investigating localization and amount of MAP2 in hypothalamo-neurohypohysial system. Western blotting showed LMW-MAP2 expression in adult posterior pituitary as well as embryonic brain. LMW-MAP2 immunoreactivity was observed in cell bodies and fine processes of astrocytes. The intensity of immunoreactivity was stronger in processes than cell bodies. In dehydrated rat, LMW-MAP2 positive astrocytes were shrunk, and intensity of LMW-MAP2 immunoreactivity in cell bodies was become stronger than well-hydrated rat. Furthermore, amount of LMW-MAP2 was increased as compared with well-hydrated rat. The change of subcellular localization of LMW-MAP2 immunoreactivity and an increase of LMW-MAP2 expression in posterior pituitary with dehydration suggest that LMW-MAP2 plays an important roll for structural plasticity of astrocytes in the posterior pituitary THE

509

ACTH-

AND

GR-IMMUNOREACTIVITIES

IN THE

BRAIN

AFTER

ADRENALECTOMY.

HITOSHI

OZAWAI),

JOY

LIONl,z),

HARRY

STEINBUSCHZ),

CANG-XIA

XIE1) AND

MITSUHIRO

KAWATAI) Dept. of Anatomy Maastricht

and Neurobiology,

University,

Maastricht,

It is known that the ACTH

Kyoto Prefectural

secretion

from anterior

the hypothalamus-pituitary-adrenal condition

of circulating

regulation manner

of Medicine,

Kyoto,

Japan11

and

pituitary

axis

However,

in pituitary

cells

cells is regulated

via glucocorticoid it has

not

by corticosteroids

receptor

been

(GR),

clearly

and ACTH-containing

depending

concluded

neurons

through on the

whether

in brain

the

is the same

or not.

Therefore, rat brain

(HPA)

corticosteroids.

of ACTH-secretion

University

The Netherlands21

in the present study, we investigated

after adrenalectomy

ACTH-immunoreactivity

(ADX),

decreased

the ACTH-immmunoreactivity reduction

of GR-immunoreactivity

observed.

These results

glucocorticoid-

feedback

suggest

using

the change

specific

in the soma

eminence

where

and GR-immunoreactivity

and GR antibodies.

of hypothalmic

in fibers of median in the area

ACTH

ofACTHACTHclearly

increased.

ACTH-containing

that the ACTH-containing

system via GR as well as HPA axis.

neurons

After

containing

in the

4 day-ADX,

neurons,

On the other hand,

neurons

were

might be also regulated

the

although

present through

the was the