close

Вход

Забыли?

вход по аккаунту

?

The anatomical distribution of the interscapular and parotid glands of the insectivorous bats Tadarida Myotis and Pipistrellus.

код для вставкиСкачать
T H E ANATOMICSL DISTRIBUTION O F
T H E INTERSCAPULAR AND PAROTID GLANDS
O F T H E INSECTIVOROUS BATS TADARIDA,
MYOTIS AND PIPISTRELLUS
PHILIP H. KRUTZSCH AND S . EDWARD SULKIN
Department of Anatomy, School of Medicine, The University o f Pittsburgh,
Pittsburgh 1.9, Pennsylvania and Department of iifiCTObiOlOgy,
University of Texas Southwestern Medical School, Dallas, Texas
XINE FIffURES
The almost simultaneous isolation in 1953 of the rabies
virus from insectivorous bats in Flordia (Venters, Hoffert,
Scatterday and Hardy, '54) and in Texas (Sullivan, Grimes,
Eads, Menzies and Irons, '54; Burns and Farinacci, ' 5 5 ) together with the occurrence of at least two human rabies
deaths believed to have resulted from exposure to bats in
this country (Sulkin and Greve, '54; Irons, Eads, Grimes and
Conklin, ' 5 7 ) , stimulated studies t o evaluate the significance
of these animals in the ecology of rabies in the United States.
During the course of studies to determine the mechanism by
which these animals may serve as persisting reservoirs for
the rabies virus in nature it was observed by us (Sulkin,
Krutzsch, Wallis and Allen, '57) that the interscapular brown
fat provides a depot for storage for the virus.
The observation by Wimsatt ('55) that a large lobe of the
parotid gland in the fruit eating bat Artibeus jamaicewsis
(family Phyllostomatidae) extends into the interscapular
space to be intimately associated with the brown fat, together with the classic role played by the salivary glands in
rabies infection, stimulated us to investigate the morphological relationship of the interscapular brown fat and parotid glands in the species of bats used in our experiments.
39i
398
PHILIP H. KRUTZSCH AND S. EDWARD SULKIN
It will be demonstrated that the interscapular brown f a t of
the insectivorous species of bats under study, Tadarida braxilieasis nzezicaaa (family Molossidae) and My Otis lucifugus
lucifugus and Pipistrellus sub flauus subfEauus (family Vespertilionidae), do not contain parotid gland tissue. Comparison will be made between our observations and those of
Wimsatt ( ' 5 5 ) regarding the interrelationship between the
interscapular brown f a t and parotid gland tissue.
MATERIALS AND METHODS
Eight (4males and 4 females) T'ndaridn braxilieasis me$&
caaa, 6 (3 males and 3 females) Myotis lucifugus lucifugus
and 6 (3 males and 3 females) Pipistrellus subflauus subfEuvus taken in November and December were used in this
study. The animals, all adults, were killed by ether.
I n order to facilitate the study of the blood supply to the
interscapular brown fat the arteries in two specimens of Myotis lucifugus and Pipistrellus subflauus were injected with a
colored vinyl resin. Approximately $4 em3 of vinyl was introduced into the left ventricle through a 26 gauge needle on a
5 em3 hypodermic syringe. The bats were then immersed in
a 10% neutral formalin solution for fixation.
I n half of the remaining representatives of all species the
abdomen was incised and the skin over the interscapular
fossa split and opened to expose the tissue underneath. These
individuals were then immersed in 10% neutral formalin for
fixation. Since the interscapular and parotid glands are
bilateral, one member of each pair was washed, dehydrated
in alcohol and embedded in paraan. Sections from these tissues were cut at 6 p, and several were mounted along with a
section of rat colon and parotid (as a check on the effectiveness of the stains) on each slide. These slides were stained
as follows : Masson trichrome stain ; Harris's hematoxylin
and eosin for general cytology; iron hematoxylin and metachromatic dyes (Lillie, '54) for mucins : Mayer's mucicarmine
method for mucins ; and McManus ( '46) periodic acid-Schiff
(PAS) procedure for miicopolysaccharides.
INTERSCAPULAR AND PAROTID GLAND O F BAT
399
The other member of the pair was sectioned on the freezing
microtome at 10 p, and then slides were stained alternately
with either Sudan black or Nile blue sulfate for fats.
Pieces of the interscapular brown fat and parotid glands
were excised from the remaining bats and were immersed
for fixation in Helly’s fluid, Zenker’s fiuid, Bouin’s fluid and
absolute ethyl alcohol, respectively. All of these tissues were
embedded in paraffin and sectioned serially at 6 p, A section
of rat colon and parotid gland was included on each slide as
a check on the effectiveness of the stains.
The Zenker’s and Bouin’s fixed tissues were stained according to the following procedures : Masson trichrome stain,
Harris’s hematoxylin and eosin for general cytology, Gomori’s ( ’41) chrome alum hematosylin for salivary zymogen
granules and mucin and Steedman’s Alcian blue stain for
acid mucopolysaccharides.
The absolute alcohol fixed tissues were stained according
to Mayer ’s mucicarmine technique without counter staining
in order to demonstrate only the mucins.
The Helly’s-fixed tissues were stained according to the McManus ( ’46) periodic acid-Schiff (PAS) procedure to demonstrate mucins and glycogen.
Dissections of the interscapular brown fat and parotid
glands were performed under a dissecting microscope, and
line drawings were made of these by Dr. M. Jollie.
OBSERVATIONS
The anatomical distribution of the interscapular brown fat
and parotid glands of Tadarida braxilieasis mesicana and
Pipistrellus subflavus subjlavus is depicted in figures 1 to 4.
These figures are of the dorsal and lateral aspects of dissected
specimens and demonstrate the relative size and relations of
the interscapular brown fat and parotid glands to one another.
No figures for Myotis lwcifugus are included because the
structure of this species is essentially that of Pipistrellus
subfEavus.
400
PHILIP H. KRUTZSCH A N D S. EDWARD SULHIN
Parotid glands. The gross characteristics of the parotid
glands of these three species of bats are nearly alike agreeing in general proportions and in anatomical distribution.
The glands (see figs. 1-4) are relatively small (3-5 mm in
diameter) structures flattened against the curved dorso-lateral
surface of the occipital bone and partly encircle the external
auditory canal from above and behind. There is a flattened
finger-like process of glandular tissue from the main body
of the parotid which extends beneath the occipito-pollicalis
muscle ventro-laterally to the ramus of the mandible to terminate against the mylohyoid muscle at the point where the
masseter attaches to the mandibular ramus. There are no
parotid projections passing into the interscapular fossa in
these species of bats as is characteristic in Artibeus jamaicensis (Wimsatt, '55). The parotid gland and interscapular
brown fat at some seasons of the year are in contact at the
occipital area but each is encapsulated in its own connective
tissue and is distinct from neighboring tissue.
Stenson's duct originates from the ventro-lateral projection of the parotid gland and passes across the masseter at
the ramus of the mandible curving upward to reach the buccal cavity at the level of the second molar tooth. There is a
hiatus between the two parotid glands both dorsally on the
base of the skull and ventrallv between the mandibular rami.
Interscapular brown. fat. The interscapular brown fat of
Tadarida b. mexicaw, Myotis lucificgus and Pipistrellus subfEavus consist of two, nearly symmetrical, triangular multilobulated lobes that occupy either side of the mid-dorsal depression between the scapulae (see figs. 14). From the lateral
side of the dorsal interscapular segment an irregularly shaped
process (cervical lobe) passes superficially, laterally and ventrally around the base of the neck to terminate in the supraclavicular fossa. The dorsal segment (dorsal lobe) lies superficial to the dorsal musculature and together with the cervical
segment can be removed in toto if the dissector divides the
thin connective tissue slips, attaching them to the underlying
WOCC. POLL.
n
P. GL.
occ. POLL
..BE
+D.L.B.F.
M. occ. POLL.
-
2
Fig. 1 Drawing of dorsal aspect of a dissected specimen of Tadarido b.
fat
to the parotid gland. The resemblance between interscapular brown adipose
tissue and salivary glands is slight.
Fig. 2 Drawing of lateral aspect of a dissected specimen of Tadarida b.
mexicana showing the relations of the dorsal and cervical lobes of interscapular
brown adipose tissue to the parotid gland.
Fig. 3 Drawing of dorsal aspect of dissected specimen of Pipistrellus subfirnus
showing the relation of the dorsal lobe of the interscapular brown f a t to the
parotid gland. The resemblance between the interscapular brown adipose tissue
and salivary glands is slight.
Fig. 4 Drawing of lateral aspect of a dissected specimen of Pipistrellus subflawus showing the relation of the dorsal and cervical lobes of the interscapular
brown f a t to the parotid glands.
Abbreviations: C.L.B.F., cervical lobe brown f a t ; D.L.B.F., dorsal lobe brown
f a t ; M.OCC.POLL., occipito-pollicalis muscle ; P.QL., parotid glands j SUBKGL.,
submaxillary gland.
401
mexicana to show the relation of the dorsal lobe of the interscapular brown
402
PIIILIP H. KRUTZSCH AND S. EDWARD SULKIN
investing fascia and the nerves and blood vessels which enter
their deep surface.
The f a t lobes may vary somewhat in size in different seasons of the year. During the summer months the lobes are
smallest and each member of the bilateral pair may be clearly
Fig. 5 Schematic drawing of lateral aspect of a dissected specimen of Pipistrellus subflawus showing the nature of the arterial supply and venous drainage
of the interscapular brown fat. A.R.F., artery t o brown f a t ; D.L.B.F., dorsal
lobe brown f a t ; E.C., external carotid artery; E. J., external jugular vein; I.C.,
internal carotid arteSy; I.J., internal jugular vein; S.A., subclavian artery ;
S.V., subclavian vein; V.A., vertebral artery; V.B.F., vein from brown fat.
INTERSCAPULAR A N D PAROTID GLAND O F BAT
403
separate from the other. At this season the interscapular
lobes usually occupy a smaller part of the interscapular fossa
and most often do not reach the occipital region of the head.
I n the fall and winter, season of hibernation, the interscapular lobes of the brown fat are much larger. One lobe frequently may overlap the other, and both often extend from
the occipital region of the slmll caudalward in the interscapular fossa to a position slightly distal to the inferior angle of
the scapulae.
Both the dorsal and cervical lobes of the interscapular
brown fat are divided into numerous irregular shaped lobules
by fascia1 septa which penetrate from their loose connective
tissue capsule. The blood vessels and nerve fibers which supply the brown fat cells can be seen to enter the lobules along
these septa. The vascular supply of the interscapular and
cervical lobes of brown €at is from the thyrocervical trunk.
Branches from this main trunk (characteristic of the transverse cervical arteries of man) enter the deep surface of this
gland (see fig. 5 ) . Vascular drainage of the brown fat is
accomplished by several large vessels which we identify as
large contributors to the formation of the external jugular
vein (see fig. 5 ) .
Nerves reach the dorsal lobe of interscapular brown fat on
its deep surface and are apparently from the dorsal rami of
the lower cervical and upper thoracic spinal nerves. The cervical lobe appears to be innervated by branches from the cervical and brachial plexuses; these fibers likewise enter the
deep surface.
Microscopic observntiotas
We are concerned chiefly with those morphological features
which will allow identification of the parotid gland and brown
adipose tissue in order that we can ascertain their exact
relationship, if any, in the interscapular region. It is not our
purpose to present a detailed description or analysis of these
tissues. Certain comparisons will be made with Wimsatt’s
( ’55) finding regarding Artiheus, because of the peculiar
403
PHILIP H. KRUTZSCH A N D S. EDWARD SULKIN
morphological relationship of the parotid gland and the interscapular brown fat in this bat.
Interscapular brown fat tissue. Microscopic examination
of the interscapular tissue in all three species of bats supports our gross anatomical observations. Serial sections demonstrate that there is no parotid tissue in the interscapular
fossa. The interscapular brown fat in all three species of
bats is histologically similar. Each interscapular lobe is composed of a large number of typical multilocular brown adipose
cells. These cells are grouped into a number of histologically
comparable lobules separated by loose, fibrous connective tissue septa (see fig. 6). The septa are penetrated by nerves
and blood vessels and often contain accumulations of white
fat cells. Frequently, but not always, we found one or more
pair of lymph nodes included in the mass of brown adipose
cells making up the interscapular lobe. Most often this lymphatic tissue was located at the cranial end of the interscapular lobe where it was enclosed by the fascia binding the f a t
body; however, the node was not incorporated in the architecture of the brown fat. There are no ducts nor alveoli of
secretory cells characteristic of parotid tissue as was the
case in the interscapular area of Artibeus jamnicensis (Wimsatt, ' 5 5 ) . Histochemical assays to demonstrate mucopolysaccharides, mucins and serous (zymogen) granules, typical of
salivary glands, were negative. I n frozen sections stained
with Sudan black the connective tissue remained unstained,
but the numerous lipid droplets in the brown adipose cells
within the septa were intensely sudanophilic. Frozen sections
stained with Nile blue sulfate produced a characteristic pink
and or blue staining of the lipid droplets as described by
Remillard ('58). The numerous lipid droplets in the cytoplasm of the brown adipose cells (see fig. 7 ) give the cells
the characteristic multilocular appearance true of brown fat.
Vacuoles, presumably where lipid droplets had been, were
distinguished in the brown f a t cells of some alcohol dehydrated Masson trichrome and Harris's hematoxylin and eosin
stained preparations.
I N T E R S C A P U L A R A S D PAROTID G L A F D O F B A T
405
Parotid gZand tissue. A histochemical and histological
appraisal of the parotid gland of these species of bats indicates that the general morphology of the gland is basically
as in other mammals.
The parotid gland is divided by connective tissue septa into numerous lobules ; there are usually well marked intralobular ducts, and the secretory cells are arranged in typical
alveoli.
Frozen sections stained with Sudan black or Nile blue sulfate disclosed only a few scattered white fat cells ; we did not
find brown adipose tissue in the parotid architecture.
Sections treated according to Mayer 's mucicarmine method
to demonstrate mucins were negative, and those treated by
Steedman's Alcian blue method for mucopolysaccharides
were weakly positive. Similar results were obtained in the
control sections of rat parotid tissue. Sections stained according to Gomori's ('41) chrome alum hematoxylin procedure for salivary zymogen (serous) granules disclosed
small chromatic granules (presumably secretion granules) in
the cytoplasm (see figs. 8 and 9). Sections treated according
t o the MchIanus (PAS) procedure are strongly positive,
presumably these cells are rich in glycogen.
The number of intralobular tubules as well as the size and
small structural details of the secretory cells appear to be
consistently different between individuals of Tadarida and
those of Myotis and Pipistrellus. Each of those two groups
differ in certain aspects from Artibeus as described by Wimsatt ( ' 5 5 ) . The parotid gland in Tndaridn b. meeicana, for
example, has fewer intralobular ducts, approximately one
per high power (350 X ) field (see fig. 8), as compared to
three o r 4 per high power (350 X ) field (see fig. 9) in similar
areas of preparations in Myotis Eucifugzcs and Pipistrellus
subflauus. Figures from the work of Wimsatt ( ' 5 5 ) and Dalquest and Werner ('51) suggest that the intralobular ducts
in Artibezcs are at least as abundant or perhaps might exceed
in number the ducts in the latter two genera. Wimsatt ('55)
noted that the secretory cells of the parotid alveoli of Artibeus
406
PHILIP H. KRUTZSCH AND S . EDWARD SULKIN
differed from the classical descriptions of serous secretory
cells. The nuclei were small, densely chromatie and typically
displaced toward the base of the cell. He describes the cytoplasm as virtually achromatic, without basal concentrations
of chromidial substance or xymogenic granules.
We found the secretory cells of the parotid alveoli in
T'adarida to differ less sharply from the classical description.
For example, although the nuclei were densely chromatic,
they were round, relatively large, and in 7040% of the eases
displaced toward but not at the base of the cell. The individual secretory cells of Tudar-idn are larger than those of MyOtis lucifugus and Pipistrellus subfEavus. The cytoplasm of
the secretory cells of all three bats, in most instances, was
chromatic and stained to an intensity normal for the technique employed. The nuclei of the secretory cells of Myotis
and Pipistrellus were less rounded and more often placed basally, somewhat reminiscent of mucous cells. Our observations
agree with Wimsatt ( ' 5 5 ) on the absence of basal concentrations of chromidial substances. We noted small secretory
granules in the presence of Gomori's ('41) chrome alum
hematoxylin stain whereas Wimsatt ( '55) found salivary
zymogenic granules lacking. I n most of our histological preparations the cytoplasm is characteristically and uniformly
granulated as described by Wimsatt ( '55).
DISCUSSION
The striking gross similarity between parotid and interscapular glands pointed out by Wimsatt ('55) for the tropical
fruit bat Artibeus is not true in the bat species l'adarida b.
mexicauza, Myotis lucifugus and Pipistrellus subfEauus. The
parotid glands in these species are small, rounded, limited to
the occipital and mandibular areas and enclosed in a fascia1
covering which partly hides their lobular appearance and
separates them from the cervical and dorsal lobes of interscapular brown fat. The so called interscapular glands, on
the other hand, are relatively large, triangular-shaped,
INTERSCAPULAR A N D PAROTID GLAND O F BAT
407
strongly lobulated structures present in the interscapular
fossa, where they are invested by a loose fascia1 covering that
isolates these “glands” from neighboring tissue.
Microscopically the brown adipose tissue is essentially the
same as that of other mammals. The interscapular brown
fat of Myotis Zucifugus has been described in detail by Remillard (’58), and the structure of this tissue in Tadarida 6.
mezicalza and Pipistrellus szcbfEavus fits this general description. Our histochemical and histological preparations clearly
confirm, at the microscopic level, the absence of parotid tissue in the interscapular fossa. lllicroscopic examinations of
the parotid glands reveal that multilocular brown fat cells
are absent from their architecture. It would seem that there
is little chance that a mistake in the gross identification of
these tissues could occur. The homogeneity of each of the
tissues further precludes the possibility of contamination of
either brown fat tissue by salivary gland tissue or contrariwise.
LITERATURE CITED
BURNS,I(. F.,
AND C. J. FARINACCI
1955 Rabies in nonsanguinovorous bats
of Texas. J. Inf. Dis., 97: 211.
DALQUEST,
W. W., AND H. J. WERNER 1951 The interscapular gland of a
tropical fruit bat. Anat. Rec., 221: 345-354.
GOMORI, C. 1941 Observations with differential stains on human islets of
Langerhans. Am. J. Path., 17: 395-406.
IRONS,
J. V., R. B. Ems, J. E. GRIMES AND A. CONKLIN 1957 The public
health importance of bats. Texas Repts. Biol. Med., 2 5 : 292-298.
LILLIE,R. D. 1954 Histopathologic Technique and Practical Histochemistry.
Blakiston, Philadelphia, 501 pp.
MOMANUS, J. F. A. 1946 Histological demonstration of mucin after periodic
acid. Nature, 258: 202.
REMILLARD,G-L. 1958 Histochemical and microchemical observations on the
lipids of the interscapular brown f a t of the female vespertilionid bat
Myotis lucificgus Zucifugus. AM. New York Acad. Sci., 72: 1-68.
SULKIN,
8. E., AND M. J. GREVE 1954 Human rabies caused by bat bite. Texas
J. Med., 60: 620.
SULEIN,
S. E., P. H, K ~ J T z S C H , C. WALLIS AND R. ALLEN 1957 Role of brown
f a t i n pathogenesis of rabies in insectivorous bats (Tadarida b.
mezicana). Proc. Soc. Exp. Bid. Med., 96: 461-464.
SULLIVAN,
T. D., J. E. GRIMES,R. B. EADS,J. C. MENZIESAND I. V. IRONS1954
Recovery of rabies virus from colonial bats in Texas. Public Health
Repts. (U.S.), 69 766-768.
.-
408
PHILIP H. HBUTZSCH AND S. EDWARD SULKIN
VENTERS,H. D., W. R. HOFFER,J. E. SCATTERDAY AND A. V. HARDY 1954
Rabies in bats in Florida. Am. J. Public Health, 4 4 : 182.
WIMSATT,W. A. 1955 On the nature of the interscapular gland of the tropical
American fruit bat Artibens jamaicsnsis Leach. Anat. Rec., 121 :
549-564.
ADDENDA
Since this manuscript was submitted for publication a third fatal human case
of rabies due to an encounter with a rabid bat has come to our attention
(Lennette, E. A., et al, J. Lab. and Cliu. Med., in press).
PLATE 1
EXPLANATION O F FIGURES
Photomicrograph showing interscapular brown f a t ( b f ) of Tadarida b.
Note
the absence of ducts and the interlobular space (ils) between adjacent
lobules ; this is characteristic of interscapular brown fat. Sections were
stained in hematoxylin and eosin. X 150.
mexicana separated from white f a t (wf) by connective tissue (c).
Photomicrograph of brown adipose tissue from the dorsal lobe of the interscapular gland of Pipistrellus sz~bflawi~sshowing the typical multilocular
(mlc) appearance of the cells. Sections were stained in hematoxylin and
eosin. X 350.
Photomicrograph showing parotid gland tissue from Tadarida b. mezicana.
Note the single intralobular duct (ild), the large size of indiTidua1 alveolar
cells and more centrally placed nuclei as compared t o alveolar cells of
Pipistrellus subflawus (fig. 9 ) . The granular character of the cytoplasm is
typical. Sections were stained by the Gomori chrome alum hematoxylin
procedure. X 350.
Photomicrograph showing parotid gland tissue from Pipistrellus subpavus.
Note the numerous intralobular ducts (ild), the basal position of nuclei in
the alveolar cells, the granular character of the cytoplasm and the smaller
size of individual alveolar cells as compared to those of Tadarida (fig.8).
Sections were stained by the Gomori chrome alum heinatoxylin procedure.
X 350.
I N T E R S C A P U L A R AND PAROTID GLAND O F BAT
PHILIP H . ILRUTZSCH A N D 8. EDWARD SULRIN
409
PLATE 1
Документ
Категория
Без категории
Просмотров
0
Размер файла
775 Кб
Теги
distributions, interscapular, insectivorous, tadarida, pipistrellus, parotit, gland, anatomical, batse, myotis
1/--страниц
Пожаловаться на содержимое документа