Plasticity of developing serotonergic neuron

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THE INFERIOR COLLICULAR PROJECTION TO THE CAUDAL THALAMIC REGION IN THE MACAQUE MONKEY HIROAKI MATSUOKA Department of Anatomy(3rd

Division), Gkayama University

, 700, Japan. Japanese( Macaca fuscata ) monkeys weighing 3-10 kg were used in the study.

School of Medicine, Okayama

The unilateral injection of hcrseradish peroxidase agglutinin(WGA-HRP)

was performed

conjugated with wheat germ

into the various parts of the inferior colliculuq

After 2-3 days survival, the animals were sacrificed. Histochemical for the labeling of anterograde

demonstration

transport of WGA-HRP was according to Mesulam.

The ventral part of the central nucleus of the inferior colliculus projects fibers to the medial part of the ventral(GMv) the mt:,dialqniculate

nucleus(GM)

and anterodorsal(GMad)

divisions of

and the lateral division of the postericr nucleus

, whereas the dorsal part of the central nucleus projects fibers to the dorsolateral part of the GMV, GMad and Pol at the rostra1 two-thirds of GM.

PLASTICITY NEURON MARIKO

OF

THE

CEREBELLAR

SYSTEM: AN ANALYSIS YAMAt'iO ' ,KATSUHIKO

CALCITONIN

GENE-RELATED

PEPTIDE-CONTAINING

USING MUTANT MICE MIKOSHIBA * ,A#D

MASAYA TOHYAMA' , Department of Anatomy II, Osaka Uaiversity Medical School’ Institute and for Protein Research, Osaka University a , Suita, Osaka 565, Japan The localization of Calcitonin gene-related peptide (CGRP) like iamunoreactive structures was examined in mice with cerebellar-abnormalities such as Lurcher, Reeler and Weaver mice by means of immunocytochemistry. In the normal mice, two types of CGRP fibers were seen in the cerebellum: Thin varicose fibers and rosstte-like fibers. The former type is widely dislributed in the cerebellum, while the rosette-like CCRP fibers were found only in the granule cell layer of the anterior lobe, anteriol ansiform lobule and pyramis. In the Lurcher and Reeler mice, rosette-like CGRP fibers increased markedly in number and intensity and found in the granule cell layer throughout the cerebellum. Furthermore, thin varicose CGRP fibers also increased in number in the cerebellum cortex of these mice. However, in the only a few rosette-like CGRP fibers beaver mice, were seen and a decrease of thin varicose CGRP fibers was also found.

DEVELOPING SEROTON$RGIC NEURON, AND TOSHIHIRO MAEDA , Departments

of ’ Ophthalmology and Shiga University of Medical Science, Seta, Otsu, 520-21 Japan SerotoAergic neurons transiently innervate the developing sensory cortex in the rodent brain. This phenomenon led us to hypothesize the existence of transitory serotonergic neurons which give rise to projections during a critical period, and which then die or no longer express serotonin. We investigated this hypothesis using a new double labeling technique. WGA-apoHRP-AU was injected into the primary visual cortex of rats 9 days postnatally. The animals were examined after 2 days: majority (82.5%) of retrogradely labeled cells in the raphe regions were serotonergic. Following a survival time of 8 weeks, virtually all of the original raphevisual cortical serotonergic neurons were found to be present. Relabeling these neurons by WGA-HRP revealed that 37.2% of the raphe neurons which had projected to the neonatal visual cortex no longer possessed such projections. The present study raised a possibility that spontaneous denervation and reinnervation of serotonergic neuron take place during the brain maturation.