Angioarchitectural classification of the fungiform papillae on the dorsal surface of the bullfrog tongue

= = = = = = = = = ANNALS

or ANATOMY

=========

Angioarchitectural classification of the fungiform papillae on the dorsal sudace of the bullfrog tongue Koei Ojima, Mamoru Takeda, Chikako Saiki, Toshiaki Takahashi, and Shigeji Matsumoto Department of Physiology, School of Dentistry at Tokyo, The Nippon Dental University, 1-9-20, Fujimi, Chiyoda-ku, Tokyo 102, Japan

Summary. In this study, the three-dimensional anatomy of the microvascular structure of fungiform papillae (FuP) on the dorsal surface of the bullfrog tongue has been investigated using scanning electron microscopy (SEM), and angioarchitectural classification has been carried out by means of the capillary loop (L. s) and intra-bridge structure (I. b). FuP from 30 sound bullfrog tongues were used. The following research methods were applied: SEM observation on microvascular cast specimens (MVCS) of bullfrog tongue's FuP were injected with synthetic resin (Mercox). Observation of MVSC showed that the bullfrog tongue FuP consisted of an ascending branch (A. b), L. s, I. b and a descending branch (D. b). Based upon SEM observations of MVCS, FuP can be classified into four types: A, B, C, D types according to A. b, L. s, I. band D. b. A - type (none I. b) formed from A. b, L. s, D. b only and with no I. b. B - type (one I. b) consisted of A. b, L. s, D. b and one

I. b. C - type (two I. b) were composed of A. b, L. s, D. b and two I. b. D - type (three I. b) were composed of A. b, L. s, D. b and three I. b, A. b, L. s, I. band D. b on each. A, B, C, D types were all same thickness.

the anterior margin. Microscopically, a round sensory disc, the surface of which was widely covered with a honeycomb structure, was located on the top of each FuP. There have been many studies on the ultrastructure of the lingual taste organs or the sensory papillae of frogs (During and Andres 1976; Graziadei 1969; Graziadei and DeHan 1971; Jaeger and Hillman 1976; Rapuzzi and Casella 1965; Uga and Hama 1967), of Bombina variegata (Gubo et a1. 1971), of Bufo japonicus (Iwasaki et a1. 1989), of Calyptocephalella gayi (Stensaas 1971), of Rana nigromaculata (Iwasaki et a1. 1986, 1988), of Rana rugosa (Iwasaki and Wanichanon 1991), of Rana cancrivora (Iwasaki and Wanichanon 1993), of bullfrog, Rana catesbeiana (Iwasaki and Sakata 1985; Iwasaki and Kobayashi 1989; Ojima 1990 a, b; Ojima 1995 a, b; Ojima et a1. 1996). Except for FuP of the bullfrog, Rana catesbeiana, using SEM (Ojima 1995 b), the angioarchitectural classification by MVCS of FuP have not yet been completely described. The purpose of the present study was, in detail, to classify the type of FuP in the bullfrog tongue by means of MVCS under SEM from the point of view of the relationship between the morphological characteristics and positional differences.

Key words: Bullfrog tongue - Fungiform papillae - Microvascular structure - Scanning electron microscopy

Introduction Macroscopically, FuPs were sporadically scattered among filiform papillae (FiP) and were compactly distributed over almost the entire dorsal surface of the tongue except Correspondence to: K. Ojima

Ann Anat (1997) 179: 393-397 © Gustav Fischer Verlag

Materials and methods Fungiform papillae from the tongues of 30 sound adult bullfrogs, Rana catesbeiana, of both sexes, each weighing between 200250 g, obtained from a commercial supplier, were used in this study. They were anaesthethized with an overdose of ether by the inhalation method and killed. The animals were perfused from the heart with 0.65% physiological saline solution continuing until all the blood had been replaced by the solution. After the perfusion, 0.25% glutaraldehyde solution in phosphate buffer was perfused for fixing.

The tongues were filled with synthetic resin (Mercox, CL2R 5, CL-2B 5, CL-2C 5, Dainippon Inki Chemical Co., Ltd., Tokyo, Japan) under manual pressure. The injected specimens of the tongue were immediately removed and fixed for 0.5 hr at room temperature and incubated for 1.0 hr at 55°C. The specimens were then polymerized completely, immersed in 10-15% KOH or NaOH solution for over 3 hr at room temperature until the soft tissues had been dissolved away by this solution. The finest macerated vascular samples were carefully washed 2-3 times with warm water at 45-55 °C and gently dried for 2 days at 55°C in an incubator. The MVCS of the whole tongue were mounted on specimen stubs and coated platinum sputtering. The specimens were observed under a 4000 SEM (Hitachi, Tokyo, Japan) at an accelerating voltage of 3 kY.

Results Macroscopically, the tongue of the bullfrog, Rana catesbeiana, is flat and round in shape with a bilateral apex. The tongue consisted of about 700 FuPs on the entire

dorsal surface except for the anterior margin which was elongated and directed toward the pharynx when the tongue lies within the oral cavity (Fig. 1). Microscopically, a round sensory disc, the surface of which was widely covered with a honeycomb structure, was located on the top of FuPs, which were sporadical scattered among the numerous FiPs and is encircled by the ciliated cell groups. Scanning electron microscopic observation of MVCS of FuPs was carried out at the eight points (A-H) of the four dorsal surface parts (Fig. 2). A, B at the biapical and divergent part, C, D at the divergent and central part, E, F at the central and radical part; G, H at the radical part of the tongue had been observed and classified according to the capillary loop structures. The capillary loops entering the base of the bullfrog tongue consisted primarily of an ascending and a descending branch and intra-bridge structures. In the SEM at higher magnification, MVSC of FuPs were observed at the eight points of four dorsal surface parts in detail. There were four types: A-D type of FuP from the biapical to the radical part of the tongue (Fig. 3).

t

A 000

Fig. 1. Upper overview of the macroscopic figure on the dorsal surface of the bullfrog tongue. Bilateral apical and flat tongue consisting of about 700 FuPs was posteriorly elongated and directed toward the pharynx. Macroscopic examination revealed many sizes of round FuP sporadically scattered among the numerous FiPs and distributed over the entire dorsal surface. Fig. 2 is a schematic diagram of this photograph. The arrow in left upper corner indicates direction of the pharynx. x 4 Fig. 2. A schematic diagram showing the distribution of four types: A-D of FuP on the entire surface of the Bullfrog tongue. A-H of Fig. 3 correspond to each A-H in this diagram. Mainly A-type (A, B) in the biapical and diverge part, B-type (C, D) in the divergent and central part, C-type (E, F) in the central and radical, D-type (G, H) were scattered in the radical part of the tongue dorsal surface. Indication mark: @= A-type (A, B), Ci> = B-type (C, D), ~ = C-type (E, F), @)= D-type (G, H)

394

Fig. 3. Microphotographs showing MVCS figures of each A-D type: A-type (none 1. b) (A, B) consisted of A. b, L. sand D. b only, B-type (one 1. b) (C, D) are composed of A. b, L. s, D. b and one 1. b, C-type (two 1. b) (E, F) are composed of A. b, L. s, D. b and two 1. b, D-type (three 1. b) (G, H) are composed of A. b, L. s. D. b and three 1. b. A. b = Ascending branch, D. b = Descending branch, L. s = Loop structure, 1. b = Intra-bridge structure. Bar = 50 Ilm.

395

A-type

B - type

D-type

C - type

A-type was defined as non intra-bridge (1. b) type which contained A. b, L. sand D. b only at the biapical and divergent parts (Fig. 2, 3, A, B). B-type was defined as one 1. b type which contained A. b. L. s, D. b and one 1. b at the divergent and central parts (Fig. 2, 3, C, D). C-type was defined as two 1. b type which contained A. b, L. s, D. b and two 1. b at the central and radical parts (Fig. 2, 3, E, F). D-type was defined as three 1. b type which contained A. b, L. s, D. b and three 1. b also at the radical part of the tongue's dorsal surface (Fig. 2, 3, G, H). A typical schematic patterns of the capillary loop structure of the four types of FuPs; A-D as described above were showed in Fig. 4. and A. b, L. s, D. band 1. b, consisting of four types, were all the same thickness and of a relatively simpler construction on the whole.

Fig. 4. A schematic pattern showing the capillary loop structure of each (A-D) type of FuP. A-type (none I. b) (Fig. 2, 3, A, B), B-type (one I. b) (Fig. 2,3, C, D), C-type (two I. b) (Fig. 2, 3, E, F), D-type (three I. b) (Fig. 2,3, G, H)

scattered and distributed among the large number of FiPs found on the entire dorsal surface of the bullfrog tongue as carried out under SEM. In order to classify into types, A. b, L. s, D. band 1. b were observed on MVCS of FuPs using SEM in further detail. In a previous paper dealing with the bullfrog tongue, Ojima 1995 b has reported three types: A-C from MVCS of FuP using SEM. The results of the present study show that FuP can be classified into four types; A-D according to the morphological characteristics and positional differences. More detailed comparative and angioarchitectural observations of other species of frogs are required to clarify the relationship between the morphological and positional difference of FuP and their functions. Acknowledgement. The authors wish to thank Mrs. Fusako Mitsuhashi, Dental Research Institute, School of Dentistry at Tokyo, The Nippon Dental University, for assistance with the SEM photography.

Discussion FuPs of the bullfrog tongue play an important physiological role as the sense organ for the taste. Many physiologists prefer to use them in their studies because of the many sensory discs located on the top of FuPs. It is necessary to study the precise histological features and fine vascular structure of FuP of the bullfrog tongue. There have been many studies performed on the ultrastructure of the lingual taste organs of frogs (During and Andres 1976; Graziadei 1975; Graziadei and DeHan 1975; Jaeger and Hillman 1976; Uga and Hama 1967), of Bombina variegata (Gubo et al. m971), of Bufo japonicus (Iwasaki et al. 1989), of Calyptocephalella gayi (Stansaas 1971), of Rana nigromaculata (Iwasaki et al. 1986, 1988), of Rana cancrivora (Iwasaki and Wanichanon 1993), of Rana catesbeiana (Iwasaki and Sakata 1985; Iwasaki and Kobayashi 1989; Ojima 1990 a, b; Ojima 1995 a, b; Ojima et al. 1996; Rapuzzi and Casella 1965). However, among these papers, except for the three types A, B, C of FuP of the bullfrog, Rana catesbeiana observed for the first time using SEM (Ojima 1995 b), the angioarchitectural classification by means of MVCS of FuP has not yet been completely reported. The present study revealed that the classification by MVCS of FuPs, sense organs for taste, were sporadically

References DUring MV, Andres KH (1976) Ultrastructure of taste and touch receptors of the frog's taste organ. Cell Tissue Res 165: 185198 Graziadei PPC (1969) The ultrastructure of vertebrate taste buds. In Pfaffman C (ed) Olfaction and Taste. Rockefeller Univ Press, New York, pp 315-330 Graziadei PPC, DeHan RS (1971) The ultrastructure of frog's taste organs. Acta Anat 80: 563-603 Gubo G, Lametschwandtner A, Simonsberger P, Adam H (1978) Licht- und rasterelektronenmikroskopische Untersuchungen an Gaumen und Zunge der Gelbbauchunke. Bombina variegata L. Anat Anz 114: 169-178 Iwasaki S, Sakata K (1985) Fine structure of the lingual dorsal surface of the bullfrog. Okajimas Folia Anat Jpn 61: 437-450 Iwasaki K, Miyata K, Kobayashi K (1986) Studies on the fine structure of the lingual dorsal surface in the frog, Rana nigromaculata. Zool Sci 3: 265-272 Iwasaki S, Miyata K, Kobayashi K (1988) Fine structure of filiform papillae epithelium from the tongue of the frog, Rana nigromaculata Zool Sci 5: 61-68 Iwasaki S, Kobayashi K (1989) Fine structure of the lingual dorsal epithelium in the bullfrog, Rana Catesbeiana. Zool Sci 6: 259-267 Iwasaki S, Miyata K, Kobayashi K (1989) Fine structure of the

396

Ojima K (1995 a) Intravitam staining figure of fungiform papillae in bullfrog tongue. Shigaku (Odontology) 82: 990-997 Ojima K (1995 b) Microvascular structural study offungiforn papillae in bullfrog tongue. Shigaku (Odontology) 82: 998-1005 Ojima K, Takeda M, Saiki C, Matsumoto S (1996) Angioarchitectural classification of the fungiform papillae in the cat tongue. Zool Sci 13: 533-535 Rapuzzi G, Casella C (1965) Innervation of the fungiform papillae in the frog tongue. J Neurophysiol28: 1154-1165 Stensaas LJ (1971) The fine structure of fungiform papillae and epithelium of the tongue of a South American toad, Calyptocephalella gayi. Am J Anat 131: 443-462 Uga S, Hama K (1967) Electron microscopic studies on the synnaptic region of the taste organ of carps and frogs. J Electron Microsc 16: 269-276

lingual dorsal epithelium of the japanese toad, Bufo japonicus (Anura: Bufonidae). Zool Sci 6: 681-689 Iwasaki S, Wanichanon C (1991) Fine structure of the dorsal lingual epithelium of the frog, Rana rugosa. Tissue and Cell 23: 385-391 Iwasaki S, Wanichanon C (1993) An ultrastructural study of the dorsal lingual epithelium of the crab-eating frog, Rana cancrivora. J Morphol 215: 89-100 Jaeger CB, Hillman DE (1976) Morphology of gustatory organs. In: Lind R, Precht W (eds) Frog Neurobiology. Springer, Berlin Heidelberg New York Tokyo, pp 55~06 Ojima K (1990 a) The movemental mechanism and the vascular structure of the tongue (XXIII) - Vascular structure of the fungiform papillae by stain injection sample. Shigaku (Odontology) 78: 178 Ojima K (1990 b) The movemental mechanism and the vascular structure of the tongue (XXIV) - Vascular structure of fungiform papillae by 5% added indian ink injection sample. Shigaku (Odontology) 78: 611

Accepted March 4, 1997

Bucbbesprecbung Miehlke, Adolf. Geschichte der Mikrochirurgie. Die historische Entwicklung in den verschiedenen operativen Disziplinen. Unter Mitwirkung von Ulrich Trohler. 176 Seiten, 103 Abbildungen und Tabellen. Leinen. Urban & Schwarzenberg, Munchen-Wien-Baltimore 1996. DM 78,00; oS 570.00, sFr71.00. ISBN 3-541-16871-4 Der Autor der vorliegenden Monographie ist einer der Pioniere der Mikrochirurgie. Als Lehrstuhlinhaber fUr HNO-Erkrankungen hat er die Entwicklung auf diesem speziellen operationstechnischen Gebiet entscheidend mitgepragt. Seine Leistungen sind in zahlreichen Publikationen dokumentiert. 1m Alter von 79 lahren legt er nun - nach AbschluB eines Zweitstudiums der Geschichte, Kunst- und Medizingeschichte und Promotion zum Dr. phil. - dieses Werk vor. Die Anfange der Mikrochirurgie miissen im letzten lahrhundert gesucht werden. Alles begann mit den industriellen Fortschritten und mit der Entwicklung leistungsfahiger Mikroskope. Drei Namen stehen hier im Vordergrund, der des Mechanikers Carl Zeiss, des Physikers Ernst Abbe und des Chemikers und Glaslaborbesitzers Otto Schott. Sie entwickelten binokulare Mikroskope, die durch die verbesserten Sichtverhaltnisse der Chirurgie neue Dimensionen erschlossen. Die Geschichte der Mikrochirurgie ist also gleichzeitig eine Geschichte der mikroskopischen Technik.

Die Mikrochirurgie ist keine in sich abgeschlossene Spezialdisziplin, also kein eigenes operatives Fach. Es handelt sich urn ein spezielles operationstechnisches Verfahren, das mit Hilfe des Operationsmikroskopes durchgefUhrt wird und besondere Anforderungen an den Operateur stellt. Die EinfUhrung dieses mikroskopischen Verfahrens in die einzelnen operativen Facher verlief zeitlich sehr unterschiedlich. C. O. Nylon fuhrte 1921 die Mikrochirurgie des Mittelohres ein. Von da an fand sie Eingang in nahezu aile operativen Eicher. Die spektakularen Erfolge von Mikroreplantationen in den letzten 30 lahren basieren auf den Erfolgen der MikrogefaBchirurgie und auf der Moglichkeit, durchtrennte periphere Nerven mikrochirurgisch wiederherzustell en. Gerade auf diesen Gebieten eroffnen sich he ute noch nicht abschatzbare Moglichkeiten. Das Buch ist in 13 Kapitel gegliedert. Es werden die technischen Voraussetzungen und Fortschritte von der Lupenchirurgie bis zur mikroskopischen Chirurgie der operativen Facher anschaulich beschrieben. Viele der den Text begleitenden Fotografien von Personlichkeiten, die neue Anwendungsbereiche erschlossen haben, entstammen dem Privatbesitz des Autors. Das Buch enthalt ein Personenverzeichnis und ein Sachregister, feroer ein umfangreiches Literaturverzeichnis. Es kann somit auch gut als Nachschlagewerk und als Quelle fUr weiterfiihrende Literatur benutzt werden. Uda Schramm, Lubeck

397