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INTRAMUCOSAL DISTRIBUTION AND TRAVELING OF PERIPHERAL SENSORY NERVE FIBERS IN THE LARYNX OF CATS

YASUMASAITANAKA * I ) , YOSHIKAZU YOSHIDA .2 ) , MINORU HIRANO .2 ) , MASATOSHI MORIMOTO I) and TAKESHI KANASEKI " l )Dept, of Anatomy, Faculty of Medicine, Kyushu Univers i ty , 3 - I - I Maidashi, Higashiku, Fukuoka 812, 2)Dept. of Otolaryngology, School of Medicine, Kurume Univers i ty , 67 Asahi-machi, Kurume 830, Japan

The intramucosal d i s t r i b u t i o n and t rave l ing of peripheral sensory nerve f ibers in the larynx of cats were studied by i n jec t i ng wheat germ agglut in in-horseradish peroxidase (WGA-HRP) into the nodose ganglion. For the operation and the perfusion of the f i x a t i v e , the experimental animals were deeply anesthetized.

We confirmed that labeled terminals were to be seen in the nucleus t ractus s o l i t a r i i and that no labeled neurons were to be seen in the nucleus ambiguus or the dorsal motor nucleus of the vagus of the medulla. We then traced labeled nerve f i ve rs in the larynx. Labeled peripheral sensory nerve f ibers of the in ternal branch of the superior laryngeal nerve divided into three rami: the an ter io r , the medial, and the poster io r ramus. The anter io r ramus supplied the laryngeal aspect of the e p i g l o t t i s . The medial ramus supplied the p l ica a ryep ig lo t t i ca , the postero la tera l aspect of the arytenoid, and the ros t ra l surface of the vocal fo ld i p s i l a t e r a l l y . The poster ior ramus supplied the i p s i l a t e r a l laryngeal part of the hypopharynx, and the i p s i - l a te ra l Galen's anastomosis. I t also supplied the b i l a te ra l dorsal part of the subg lo t t ic port ion together with the medial ramus. We found a foramen on the c r i co id ca r t i l age . This foramen was penetrated by the medial and the poster ior rami of the in ternal branch of the superior laryngeal nerve. In addi t ion, a few f ibers from the poster ior branch of the i n f e r i o r laryngeal nerve were observed penetrat ing th is foramen. Labeled sensory nerve f ibers of the poster io r branch of the i n f e r i o r laryngeal nerve were div ided into two rami: the ramus of Galen's anastomosis and the ramus perforans which passed between the la te ra l cr icoarytenoid and the thyroarytenoid muscles. The ramus perforans innervated the subg lo t t i c port ion of the laryngeal mucosa. There was no port ion of the mucous membrane to which sensory innervat ion was supplied by the external branch of the superior laryngeal nerve.

THE LAMINAR DISTRIBUTION, SIZES, AREAL DENSITY, AND MORPHOLOGY OF GABAERGIC NEURONS IN THE PREFRONTAL, MOTOR, AND SOMATOSENSORY CORTICES IN MACAQUE MONKEYS

* TOMIO ARIKUNI, NOBUO TAKASU , TOSHIO NAKATANI, EIJIRO ADACHI, KYOKO WATANABE, KISOU KUBOTA, and HIROSHI KIMURA Dept. Anat. Osaka Univ. Med. Sch., 4-3-57 Nakanoshima, Kitaku, Osaka 530, Japan; Dept. Neurophysiol. Primate Rez. Inst. Kyoto Univ., Inuyama, Aichi 484, Japan; and Dept. Anat. Shiga Univ. Med. Sci., Ohtsu 520-21, Japan

The laminar distribution, sizes, areal density, and morphology of GABAergic neurons were studied light microscopically in the prefrontal (area 46), motor (area 4), and somatosensory (area 3a) cortices in the macaca fuscata and macaca irus. GABAergic neurons were identified by immunocytochemical localization of GABA using the avidin-biotin-peroxidase complex (Kimura et al., Neurosci. In press), and light microscopic images of these neurons were fed directly into an image analysing system using a personal computer. GABAergic neurons are present in all cortical layers. In areas 46 and 3a, GABAergic neurons appear to be concentrated in layers II, IIIA, and IV, while in area 4 GABAergic neurons are distributed mainly in layers II and IIIA. Sizes of the soma of GABAergic neurons range from 4 to 28 tim. The mean diameters (Heywood diameter) of these neurons in areas 46, 4, and 3a are 11.6 -+ 4.2 Um (S.D.) (n=759), 10.52 ± 3.6 tlm (n=424), and 9.1 i 3.3 Bm (n=419), respectively. The large GABAergic neurons, classified as those with diameters more than 15 Urn, are mainly found in layers III and V in each one of the areas, but they constitute 19.6 % of labeled neurons in all cortical layers in area 46, 9.6 % of those in area 4, and 5.4 % of those in area 3a. Numbers of GABAergic neurons in a vertical cortical area of I0000 tlm in areas 46, 4, and 3a are 4.0, 1.6, and 3.2 neurons, respectively. The most common cell type of GABAergic neurons observed in area 46, 4, and 3a is a small stellate or multipolar cell. Other cell types include bitufted, tufted, bipolar, basket, and horizontal cells. A large number of GABA-containing punctate structures are present throughout the neuropil, but some puncta are located adjacent to non-labeled cell bodies. GABA-containing fibers are also present in the white matter in areas 46, 4 and 3a. These results mean that in the monkey cortex GABAergic inhibitory circuits are different between cytoarchitectonic regions.