Production of hamster monoclonal antibody which inhibits outgrowth of olfactory bulb efferent fibers

S295

EARLY DEVELOPMENT AXONAL PROJECTIONS

663

KEIKO MUGURUMA

and YASUYOSHI

OF CATECHOLAMINERGIC AND SEROTONERGIC IN THE FETAL RAT BRAIN.

NEURONS

AND THEIR

WATANABE

Department of Neuroscience, Osaka Bioscience Institute, Suita-shi, Osaka 5650874 Catecholaminergic and serotonergic projections are thought to play crucial roles in establishment of the functional architecture of the brain. In the adult brain, these projections extensively arising from brain stem have been well studied, whereas those in

the fetal brain were still unknown. To determine the early development

of these neurons, the immunohistochemical

studies were

performed in whole-mount preparations and serial coronal and sagittal sections of the fetal rat brain [embryonic day (E)l I-E201 using antibodies against tyrosine hydroxylase (TH), dopamine D-hydroxylase (DBH), tryptophan hydroxylase, and serotonin. Serotonin-containing neurons were identified first at El2 which form a cluster just caudal to the mesencephalic flexure. while the mote caudal ones appeared at E13 in the medulla. Ascending fibers arising from rostral one entered the telencephalon at E16. TH and DBH immunoreactive neurons first appeared at El2 sporadically and then gradually shifted in their adult-like patterns.

664

PAX-6 IS REQUIRED FOR THE THALAMOCORTICAL

PATHWAY

FORMATION

HITOSHI KAWANO’, TETSUYA FUKUDA’, MASAO HORIE’, NORIKO 0SUM13, KAZUHIRO

IN FETAL RATS. ET04 and KOKI

KAWAMURA2

‘Dept. of Anat. & EmbryoI., Tokyo Metropolitan Inst. for Neurosci.Fuchuu 183-8526, 2Dept. of Anat. Sch. of Med., Keio, Univ., Sinjuku-ku Tokyo 160-8582, ‘Div. of Biochem. & Cell Biol., National Inst. of Neurosci., National Center of Neural. & Psychi., Kodaira 187-8502, 4Dept. of Develop. Biol., Div. of Life Sci. of Maxillo-Facial Systems, Graduate Sch. of Dentistry., Tokyo Medical and Dental Univ., Bunkyou-ku, Tokyo 113-8549, Japan Pax-6, a transcription regulatory factor, has been shown to play important roles in eye, nose and brain development. In this study, we examined, by using axonal tracing and immunohistochemical techniques, the pathway formation of the cerebral cortex in the homozygous rat with a point mutation in Pax-6 gene (rat Small eye, rSe$). Although the cortex was underdeveloped in rSey2 rSey2 embryos compared with normal embryos, cortical efferent axons which were immunoreactive for TAG-l, a neural cell adhesion molecule, were observed to develop with normal courses. In contrast, aberrant trajectory was found in thalamocortical afferent axons which were immunopositive for Ll, another neural cell adhesion molecule. Misrouting of this fiber pathway occurred in the ventral thalamus in rSey2+Se$ embryos, and Pax-6 protein was localized in the ventral thalamus in normal rat embryos, suggesting that Pax-6 regulates the expression of unidentified factors involved in the determination of the thalamocortical fiber pathway. PRODUCTION OF HAMSTER MONOCLONAL ANTIBODY WHICH INHIBITS

665 YASUFUMI

SATO, TATSUMI

During development, lateral olfactory

selected

HIRATA. and HAJIME FUJISAWA

Science, Nagoya University

Graduate School of Science, Chikusa-ku,

olfactory bulb (OB) efferents

mechanism

of LOT formation,

the MAb reduced

organotypic

number

dorsal root ganglia. Immunostaining

from OB fragments

and length of neurites

cultures was also inhibited

surface and form the monoclonal

with the MAb showed

antigen is involved in outgrowth

MAb Hl-lB4

MAb Hl-1B4

antibodies Hybrydoma

in culture, and MAb H 1- lB4 was

from OB fragments.

by MAb HI-lB4.

neurons, and thus seemed to inhibit the step of neurite outgrowth. results suggest that Hl-lB4

we produced

of a hamster which had been injected with mouse OBs and LOTS as the antigen.

were screened by their ability to affect neurite outgrowth

because

Nagoya 464-8602, Japan.

grow into a very narrow part of the telencephalon

tract (LOT). To examine molecular

(MAbs) using lymphocytes

telencephalon

OF

OLFACTORY BULB EFFERENT FIBERS

Division of Biological

supematants

OUTGROWTH

The LOT formation

in whole

did not affect cell viability of OB

did not inhibit neurite outgrowth

from the

that the antigen was located on surface of OB neurites. of OB efferent fibers.

These