Distribution of neuromedin U-like immunoreactivity in rat

$156 INTRACORTICAL INJECTION OF KAINIC ACID ENHANCES OR INDUCES SUBSTANCE P-LIKE AND ENKEPHALIN-LIKE IMMUNOREACTIVITIES IN NEURONS OF THE VISUAL CORTEX. AN IMMUNOHISTOCHEMICAL STUDY IN THE CAT KAZUO ITOH, TETSUO SUGIMOTO, YUKIHIKO YASUI, MASASHI INO* and NOBORU MIZUNO Department of Anatomy ( i s t D i v i s i o n ) , Faculty of Medicine, Kyoto U n i v e r s i t y , Kyoto 606, Japan Influences of i n t r a c o r t i c a l i n j e c t i o n of k a i n i c acid upon n e u r o p e p t i d e - l i k e immunoreactivities in neurons of the visual cortex were immunohistochemically examined in the cat. A f t e r i n j e c t i o n of k a i n i c acid i n t o the visual c o r t e x , substance P (SP)- and enkephalin ( E n k ) - l i k e immunoreactivities ( L I ) were induced or s i g n i f i c a n t l y enhanced in c o r t i c a l neurons around the peripheral part of the s i t e of k a i n i c acid i n j e c t i o n . In a d u l t cats which were anesthetized with i n t r a p e r i t o n e a l sodium p e n t o b a r b i t a l (35 mg/kg body w e i g h t ) , 0.5% k a i n i c acid was i n j e c t e d i n t o the visual c o r t e x . As c o n t r o l s , an e l e c t r o l y t i c l e s i o n or i n t r a c o r t i c a l i n j e c t i o n of 0.1 M phosphate b u f f e r was made in the visual cortex of some animals. Subsequently, the cats were allowed to survive f o r 1-30 days, and were then reanesthetized deeply and perfused t r a n s c a r d i a l l y with 0.5% l i t e r of 0.9% s a l i n e , followed by Zamboni's f i x a t i v e . Serial frozen sections through the visual cortex were prepared at 6 or 40 um thickness. The sections were processed f o r immunostaining of neuropeptides by the indirect immunoperoxidase method using the a v i d i n - b i o t i n y l a t e d peroxidase complex. The s i t e s of the k a i n i c acid i n j e c t i o n were v e r i f i e d by the Nissl s t a i n i n g of the sections. In the cats which were allowed to survive f o r 4-30 days a f t e r the i n j e c t i o n of k a i n i c acid, SP- and Enk-Ll were induced or s i g n i f i c a n t l y enhanced in visual c o r t i c a l neurons around the peripheral part of the s i t e of the k a i n i c acid i n j e c t i o n . Axon terminals with intense SP-LI were densely aggregated in layers I and V. Many neuronal c e l l bodies with intense SP- or Enk-Ll were d i s t r i b u t e d in layers I I , I I I and IV. Many of the neuronal c e l l bodies with SP- or Enk-Ll in layers I I and I I I were t r i a n g u l a r in shape, and extended an apical d e n d r i t e ; these were considered to be pyramidal neurons. The neuronal c e l l bodies with SP- or Enk-Ll in l a y e r IV were round or oval in shape, and radiated several dendrites with or w i t h o u t spines; these were considered to be s t e l l a t e neurons. In l a y e r IV, neuronal c e l l bodies with Enk-Ll were somewhat more numerous than those with SP-LI. Some neuronal c e l l bodies with SP- or Enk-Ll were also d i s t r i b u t e d in c o r t i c a l regions deeper than l a y e r IV. The coexistence of SP- and Enk-Ll was detected in only a few neuronal c e l l bodies. In control animals, n e i t h e r induction nor enhancement of neuropeptide-Ll was i n d i c a t e d .

DISTRIBUTION

MAYUMI

HONZAWA*,

*Department Department

of

TETSUJI

U-8

as

cord.

sequence

identified.

immunoreactivity

spinal

cord

and

(30 p m o l / g )

a

auditory clearly and

colon,

of the

study

revealed

functional

indicating

School

rat

has

not b e e n

rat

observed

TOHYAMA

that

both

that

system,

Among

them,

the

In

muscle

example,

addition,

and A u e r b a c h

N M U m a y be

layer

in b r a i n

involved

peptide spinal

peptides

so far

of N M U - l i k e

brain,

highest

of the

appears the

NMUI

concentration

to

intestine.

be

associated

somatosensory, and

of the

autonomic

and

pituitary,

small

cells

plexus

in the

Osaka

radioimmunoassay in the

NMUI

for

the

889-16

in p o r c i n e

distribution

found

MATSUO*

Miyazaki

is a novel

the

widely

in the

the M e i s s n e r

tracts.

by was

2)

in

regional

& HISAYUKI

Nakanoshima,

preparation found

IN R A T

Kiyotake,

of M e d i c i n e ,

uterus

the

tracts.

functions.

in b o t h

digestive

MASAYA

College,

on

NMUI

was

and c e r e b e l l a r found

in

gastro-intestinal

distinct

Medical

we e x a m i n e d

technique.

of NMUI

Immunohistochemical with

to NMU

study,

(NMUI)

immunohistochemical

IMMUNOREACTIVITY

MINAMINO*,

University

stimulant

related

this

U-LIKE

Tyr-Phe-Leu-Phe-Arg-Pro-Arg-Asn-NH

a potent

In

NAOTO

Miyazaki

Osaka

(NMU:

identified The

SUDOH*,

Biochemistry,

of A n a t o m y ,

Neuromedin

OF N E U R O M E D I N

motor,

fibers

small

were

intestine

nervous

system

530