Review article
- Perisynaptic
barrier of proteoglycans in the mature brain and spinal cord (MURAKAMI, T.)
Original articles
- Retrograde
labeling of mouse spinal descending tracts by a recombinant adenovirus (TSUKAMOTO,
Y.)
- Chondromodulin-I
expression in rat articular cartilage (KITAHARA, H.)
- The
effects of sex steroids on the formation of gap junctions between folliculo-stellate
cells; a study in castrated male rats and ovariectomized female rats (SAKUMA,
E.)
- Pathways
for movement of fluid and cells from hepatic sinusoids to the portal lymphatic
vessels and subcapsular region in rat livers (OHTANI, Y.)
- Expression
of leptin receptor (Ob-R) isoforms and signal transducers and activators of transcription
(STATs) mRNAs in the mouse taste buds (SHIGEMURA, N.)
- Fluid
and cellular pathways of rat lymph nodes in relation to lymphatic labyrinths and
Aquaporin-1 expression (OHTANI, O.)
- Structure
of the rat subcutaneous connective tissue in relation to its sliding mechanism
(KAWAMATA, S.)
- The
organization of the lamina muscularis mucosae in the human esophagus (NAGAI, K.)
Summary
Title
Perisynaptic barrier of proteoglycans in the mature brain
and spinal cord
Author
Takuro Murakami and Aiji Ohtsuka
Address
Department of Human Morphology, Functional Physiology, Biophysiological Science,
Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan
Summary
Cell bodies and their dendrites of motor neurons, motor-related neurons, and certain
other subsets of neurons such as GABAergic interneurons in the mature brain and
spinal cord possess intensely negatively charged perineuronal or perisynaptic
nets of proteoglycans which are linked to the nerve cell surface glycoproteins.
These perineuronal nets of proteoglycans are digested by chondroitinase ABC, hyaluronidase,
or collagenase, but not by endo-alpha-N-acetylgalactosaminidase, which is reactive
to the nerve cell surface glycoproteins. Aggrecan, versican, neurocan, and brevican
are members of a family of chondroitin sulfate proteoglycans that bind to hyaluronan.
Neurocan-or brevican-deficient mice showed a regionally heterogeneous composition
of proteoglycans in perineuronal nets. Aggrecan glycoforms contribute to the molecular
heterogeneity of the perineuronal nets. Proteoglycans such as phosphacan are included
in matrix-associated proteoglycans. The extracellular matrix glycoprotein tenascin-R
is accumulated in the perineuronal nets. The perineuronal proteoglycans are produced
by associated satellite astrocytes just before weaning, while the nerve cell surface
glycoproteins are produced by the associated nerve cells at earlier stages after
birth. The perineuronal proteoglycans may entrap the tissue fluid and form a perineuronal
gel layer which protects the synapses as a “perisynaptic barrier”.
Degradation of the perineuronal proteoglycans or perisynaptic barrier by treatment
with chondroitinase ABC or hyaluronidase reactivates the neuronal plasticity or
promotes the functional recovery of a severed nervous system. Another set of perineuronal
nets occurs, which are intensely positively charged and contain guanidino compounds.
It is considered that these intensely positively charged nets are intermingled
with the intensely negatively charged ones of proteoglycans.
Correspondence: Takuro Murakami, M. D., Ph. D. Professor and Chairman Department
of Human Morphology, Functional Physiology, Biophysiological Science, Okayama
University Graduate School of Medicine and Dentistry, 2-5-1, Shikata-cho, Okayama
700-8558, Japan
Phone: +81-86-235-7088, Fax: +81-86-235-7095
E-mail: em2kai@md.okayama-u.ac.jp
Title
Retrograde labeling of mouse spinal descending tracts by
a recombinant adenovirus
Author
Yasuhiro Tsukamoto, Tatsuro Yamamoto, Haruo Okado, Ken-ichi Nibu, Toshio Terashima
Address
Department of Anatomy and Developmental Neurobiology, and Department of Otorhinolaryngology-Head
and Neck Surgery, Kobe University Graduate School of Medicine, Kobe; and Department
of Molecular Physiology, Tokyo Metropolitan Institute for Neuroscience, Tokyo,
Japan
Summary
The present study tested whether a gene-transfer based upon the retrograde axonal
transport of the lacZ adenovirus is effective in the spinal descending tracts
of the adult mouse. A small volume of a replication-defective recombinant adenovirus
encoding E. coli β-galactosidase was injected into the upper lumbar
cord, and, seven days later, the mice were transcardially perfused by a fixative
solution. X-gal staining of coronal or sagittal sections of the spinal cord and
the brain revealed that many sites of origin for rubrospinal, vestibulospinal,
and reticulospinal tracts were retrogradely labeled, whereas few of the corticospinal
tract neurons were retrogradely labeled. Ependymal cells surrounding the central
canal of the spinal cord, which were located far from the injection site, showed
a high expression of β-galactosidase activity. Motoneurons around the injection
site were strongly stained by X-gal staining, and their axons in the ventral root
were anterogradely labeled. Afferent fibers in the dorsal root were labeled by
the transganglionic transport of β-galactosidase. To examine the efficacy
of the uptake and retrograde transport of HRP and adenovirus, we injected a mixed
solution of 10% HRP and recombinant adenovirus. The number of HRP-labeled corticospinal
neurons overwhelmed the number of X-gal stained ones, while the numbers of HRP-labeled
rubrospinal and subcoeruleus-spinal neurons were smaller in comparison with the
numbers of β-galactosidase-positive counterparts. The present study revealed that
the origins for the spinal descending tracts except for corticospinal neurons
could be efficiently gene-transferred by the retrograde infection of a recombinant
adenovirus. Such a difference in efficacy of retrograde infection among the spinal
descending tracts is practically important when an adenovirus-mediated gene transfer
is designed to treat certain neurological diseases affecting the spinal descending
tracts.
Correspondence: Prof. Toshio Terashima, Ph. D., Department of Anatomy and Developmental
Neurobiology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho,
Chuo-ku, Kobe 650-0017, Japan
Tel: + 81-78-382-5320, Fax: + 81-78-382-5328
E-mail: ttera@med.kobe-u.ac.jp
Title
Chondromodulin-I expression in rat articular cartilage
Author
Hiroshi Kitahara, Tadashi Hayami, Kunihiko Tokunaga, Naoto Endo, Haruko Funaki,
Yutaka Yoshida, Eishin Yaoita, and Tadashi Yamamoto
Address
Department of Structural Pathology, Institute of Nephrology, and Division of Orthopedic
Surgery, Department of Regenerative and Transplant Medicine, and Division of Ophthalmology
and Visual Sciences, Department of Sensory and Integrative Medicine, Graduate
School of Medical and Dental Sciences, Niigata University, Niigata, Japan
Summary
The localization and expression of chondromodulin-I (ChM-I), an angiogenesis inhibitor,
in the rat articular cartilage during maturation from 2 to 10 weeks of age were
examined by immunohistochemistry, Western blot analysis and ribonuclease protection
assay, and the results were compared with those in the epiphyseal cartilage. ChM-I
was found to be diffusely immunostained in the inter-territorial space of the
cartilage matrix from the intermediate to the deep layers at the immature stage.
As the articular cartilage matured, the immunoreactivity was localized around
the hypertrophic chondrocytes in the deep layer and the immunoreactivity became
weak after maturation. In contrast, the ChM-I immunoreactivity was intense in
the epiphyseal cartilage at all ages examined. ChM-I was detected by Western blotting
as a broad band or occasionally as a cluster of multiple bands (〜25 kDa) in both
the articular and the epiphyseal cartilage. The intensity of the bands decreased
gradually with age in the articular cartilage, but was unchanged in the epiphyseal
cartilage at all ages. Ribonuclease protection assay revealed that ChM-I mRNA
also decreased gradually with age in the articular cartilage in parallel with
the maturation of the articular cartilage, while no decrease in ChM-I mRNA was
found in the epiphyseal cartilage. The expression of ChM-I mRNA in the articular
cartilage was less than that in the epiphyseal cartilage at all ages. The decrease
in amount of ChM-I in the mature articular cartilage suggests that ChM-I plays
a more important role in the maintenance of avascularity in the immature articular
cartilage than in the mature one. The avascular condition may be preserved by
angiogenic inhibitors or mechanisms other than ChM-I in the mature articular cartilage.
Correspondence: Prof. Tadashi Yamamoto, Department of Structural Pathology, Institute
of Nephrology, Graduate School of Medical and Dental Sciences, Niigata University,
1-757 Asahimachi-dori, Niigata 951-8510 Japan
Phone: + 81-25-227-2151, Fax: + 81-25-227-0768
E-mail: tdsymmt@med.niigata-u.ac.jp
Title
The effects of sex steroids on the formation of gap junctions
between folliculo-stellate cells; a study in castrated male rats and ovariectomized
female rats
Author
Eisuke Sakuma, Damon C. Herbert and Tsuyoshi Soji
Address
Department of Functional Morphology, Nagoya City University Graduate School of
Medical Sciences, Nagoya, Japan; and Department of Cellular and Structural Biology,
The University of Texas Health Science Center at San Antonio, Texas, USA
Summary
We investigated the relationship between gap junction formation and the sex steroids
testosterone, progesterone and 17β-estradiol in the anterior pituitary glands
of castrated male rats and ovariectomized female rats. Male and female 30-day-old
Wistar-Imamichi strain rats were castrated or ovariectomized, and 30 days later
they were subcutaneously injected with the above sex steroids. They were divided
into six groups according to the injected materials: sesame oil (control), testosterone,
progesterone, 17β-estradiol, testosterone with 17β-estradiol, and progesterone
with 17β-estradiol. Five rats from each group were sacrificed 1, 2, 3, 4 and 5
days after the injections, and the anterior pituitary glands were prepared for
observation by transmission electron microscopy. We quantified the number of follicles
and gap junctions and calculated the rate of occurrence of gap junctions as the
ratio of the number of gap junctions existing between folliculo-stellate cells
per intersected follicle profile in electron photomicrographs. The administration
of testosterone to castrated male rats increased the rate of gap junctions between
folliculo-stellate cells; however, progesterone and 17β-estradiol did not affect
the formation of gap junctions. The administration of progesterone to ovariectomized
female rats increased the rate of gap junctions between folliculo-stellate cells;
this progesterone effect was prevented by the simultaneous administration of 17β-estradiol,
which by itself did not affect the rate of gap junctions between folliculo-stellate
cells. These observations indicate that the formation of gap junctions within
the anterior pitui-tary gland is regulated differently by sex steroids in castrated
male and ovariectomized female rats.
Correspondence: Dr. Eisuke Sakuma, Department of Functional Morphology, Nagoya
City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku,
Nagoya, 467-8601, Japan
Tel: +81-52-853-8121, Fax: +81-52-842-3210,
E-mail: esakuma@med.nagoya-cu.ac.jp
Title
Pathways for movement of fluid and cells from hepatic sinusoids
to the portal lymphatic vessels and subcapsular region in rat livers
Author
Yuko Ohtani, Bai-jun Wang, Raksawan Poonkhum and Osamu Ohtani
Address
Department of Anatomy, Faculty of Medicine, Toyama Medical and Pharmaceutical
University, Toyama, Japan; and Department of Anatomy, Faculty of Medicine, Srinakharinwirot
University, Bangkok, Tailand
Summary
It has long been a mystery how fluid and migrating cells in the hepatic sinusoids
reach lymphatic vessels in the portal tract. Here we describe previously-unknown
channels that connect the space of Disse with the portal tract in the rat liver.
Transmission electron microscopy was performed on livers injected with either
horseradish peroxi-dase (HRP) or lipopolysaccharide, and scanning electron microscopy
was carried out on livers macerated with KOH. Transmission electron microscopy
revealed the presence of channels with collagen fibers traversing the limiting
plate. A tracer study showed that HRP was in the channels as well as along inlet
venules. Dendritic cells in the hepatic sinusoids or between hepatocytes of the
limiting plate were also observed extending their pseudopodia through the channels
in the limiting plate to the interstitial space of the portal tract. Scanning
electron microscopy further showed that many channels (1-3μm in diameter) penetrated
through the limiting plate independently of blood vessels and connected the space
of Disse with the interstitial space of the portal tract. In addition, the portal
tract possessed prelymphatic vessels that were lined with fibroblast-like cells
and frequently contained dendritic cells. The initial segment of the portal lymphatic
vessels opened to the interstitial tissue space. These results indicate that fluid
and dendritic cells in the hepatic sinusoids probably pass through both the space
of Disse and the channels traversing the limiting plate, enter the interstitial
space of the portal tracts, and finally move from the prelymphatic vessels to
the portal lymphatic vessels.
Correspondence: Prof. Osamu Ohtani, Department of Anatomy, Faculty of Medicine,
Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, 930-0194
Japan
Phone: + 81-76-434-7205, Fax: + 81-76-434-5010
E-mail: osmotani@ms.toyama-mpu.ac.jp
Title
Expression of leptin receptor (Ob-R) isoforms and signal
transducers and activators of transcription (STATs) mRNAs in the mouse taste buds
Author
Noriatsu Shigemura, Hirohito Miura, Yuko Kusakabe, Akihiro Hino, and Yuzo Ninomiya
Address
Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University,
Fukuoka; National Food Research Institute, Ibaraki; Bio-oriented Technology Research
Advancement Institution, Saitama, Japan
Summary
Leptin is a hormone that regulates food intake, energy expenditure and body weight.
Our previous studies have demonstrated that the taste organ is a new peripheral
target for leptin in mice. Leptin selectively inhibits the responses of taste
nerves and receptor cells to sweet substances without affecting responses to sour,
salty, and bitter substances. Still, there is no convincing evidence for the existence
of leptin receptors (Ob-Rs) in taste receptor cells, especially the functional
isoform Ob-Rb. We investigated the expression of 5 different Ob-R isoforms (a-e)
and 6 STAT (signal transducers and activators of transcription) members in mouse
taste cells. STATs are considered to be involved in the leptin signaling via
Ob-Rb. Semiquantitative RT-PCR analysis showed that Ob-Rb was expressed in the
taste buds of the fungiform and circumvallate papillae, but not so clearly in
the surrounding epithelial tissue. The expression pattern among the three different
tissues was similar to that of the taste cell specific G-protein, α-gustducin.
The other Ob-R isoforms were widely detected in either the taste papillae or the
epithelial tissue. Among 6 STAT members, STAT3 showed the highest relative abundance
of mRNA in the taste buds. Consistently, in situ hybridization analysis
showed that while Ob-Rb and STAT3 signals were detected in some taste bud cells,
the signals were not clearly observed in the epithelial tissue cells. In conclusion,
the present study provides evidence of the existence of the leptin receptor, Ob-Rb,
and STAT3 in the mouse taste bud cells. This finding further confirms the involvement
of leptin in the control of taste sensitivities to sweet substances in mice.
Correspondence: Dr. Yuzo Ninomiya, Section of Oral Neuroscience, Graduate School
of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582,
Japan.
Tel: + 81-92-642-6312, Fax: + 81-92-642-6312
E-mail: nino@dent.kyushu-u.ac.jp
Title
Fluid and cellular pathways of rat lymph nodes in relation
to lymphatic labyrinths and Aquaporin-1 expression
Author
Osamu Ohtani, Yuko Ohtani, Colin J. Carati, and Bren J. Gannon
Address
Department of Anatomy, Toyama Medical and Pharmaceutical University, Toyama, Japan;
and Microcirculation and Lymphology Laboratory, Anatomy and Histology Department,
School of Medicine, Flinders University, Adelaide, Australia
Summary
The aim of the present study was to examine the organization of lymph fluid and
cellular pathways and distribution of the membrane water channel Aquaporin-1 (AQP-1)
in rat lymph nodes. Lymph fluid and cellular pathways within lymph nodes were
examined by fluorescent protein tracer/confocal microscopy and by scanning electron
microscopy (SEM), While the distribution of AQP-1 was studied immunohistochemically.
Tracer studies showed the subcapsular sinuses continued directly at the hilum
or via the intermediate sinuses to the medullary sinuses, and lymphatic
labyrinths originating with blind-ends in the deep cortex drained into medullary
sinuses. Afferent lymph tracers were also observed in node cortex interstitium.
By SEM, lymphatic labyrinths appeared densely filled with lymphocytes and had
few intraluminal sinus reticular cells, while medullary sinuses possessed well-developed
networks of sinus reticular cells. The presence of many lymphocytes wedged in
the walls of the lymphatic labyrinth suggested that lymphocytes migrate between
the node parenchyma and lymphatic labyrinths. AQP-1 was distributed on the membrane
of lymphatic endothelium and reticular cells as well as on both luminal and abluminal
cell membranes of high endothelial venules (HEVs). Our SEM findings support the
concept that lymphocytes migrate from the node parenchyma into lymphatic labyrinths
in the deep cortex. The nodal distribution of AQP-1 plus the presence of a polarized
distribution of ion pumps and/or ion channels in the HEV endothelium hypothesized
in our discussion could explain the mechanism of the reported lymph-to-plasma
fluid flux in lymph nodes and also facilitate the entry of afferent lymph antigens
into the node cortex interstitium.
Correspondence: Prof. Osamu Ohtani, Department of Anatomy, Toyama Medical and
Pharmaceutical University, Sugitani 2630, Toyama 930-0194, Japan
Tel: + 81-76-434-7205, Fax: + 81-76-434-5010
E-mail: osmotani@ms.toyama-mpu.ac.jp
Title
Structure of the rat subcutaneous connective tissue in relation
to its sliding mechanism
Author
Seiichi Kawamata, Junya Ozawa, Masakazu Hashimoto, Tomoyuki Kurose, and Harumichi
Shinohara
Address
Institute of Health Sciences, Hiroshima University, Hiroshima; and Department
of Anatomy, Kanazawa Medical University, Ishikawa, Japan
Summary
Mammalian skin can extensively slide over most parts of the body. To study the
mechanism of this mobility of the skin, the structure of the subcutaneous connective
tissue was examined by light microscopy. The subcutaneous connective tissue was
observed to be composed of multiple layers of thin collagen sheets containing
elastic fibers. These piled-up collagen sheets were loosely interconnected with
each other, while the outer and inner sheets were respectively anchored to the
dermis and epimysium by elastic fibers. Collagen fibers in each sheet were variable
in diameter and oriented in different directions to form a thin, loose meshwork
under conditions without mechanical stretching. When a weak shear force was loaded
between the skin and the underlying abdominal muscles, each collagen sheet slid
considerably, resulting in a stretching of the elastic fibers which anchor these
sheets. When a further shear force was loaded, collagen fibers in each sheet seemed
to align in a more parallel manner to the direction of the tension. With the reduction
or removal of the force, the arrangement of collagen fibers in each sheet was
reversed and the collagen sheets returned to their original shapes and positions,
probably with the stabilizing effect of elastic fibers. Blood vessels and nerves
in the subcutaneous connective tissue ran in tortuous routes in planes parallel
to the unloaded skin, which seemed very adaptable for the movement of collagen
sheets. These findings indicate that the subcutaneous connective tissue is extensively
mobile due to the presence of multilayered collagen sheets which are maintained
by elastic fibers.
Correspondence: Dr. Seiichi Kawamata, Institute of Health Sciences, Faculty of
Medicine, Hiroshima University, Kasumi 1- 2- 3, Minami- ku, Hiroshima 734-8551,
Japan
Tel: + 81-82-257-5410, Fax: + 81-82-257-5344
E-mail: kawamat@hiroshima-u.ac.jp
Title
The organization of the lamina muscularis mucosae in the
human esophagus
Author
Kaoruko Nagai, Tsuyoshi Noguchi, Tsuyoshi Hashimoto, Yuzo Uchida, and Tatsuo Shimada
Address
Department of Oncological Science, School of Medicine, and Department of Health
Sciences, School of Nursing, Oita Medical University, Oita, Japan
Summary
The structural organization of the lamina muscularis mucosae of the human esophagus
was studied by light microscopy and scanning electron microscopy (SEM). The organization
of the lamina muscularis mucosae varied considerably among the cervical, the thoracic,
and the abdominal part of the esophagus. In the cervical part, the lamina muscularis
mucosae was not well developed and only islets of the smooth muscle bundles were
scattered within the connective tissue. In the thoracic part,the lamina muscularis
mucosae consisted of several layers of smooth muscle bundles, individual muscle
cells of which ran in a longitudinal direction. In the abdominal esophagus near
the cardia, the muscular bundles in the lamina muscularis mucosae ran in various
directions forming a reticular configuration. The differences in density and arrangement
of the lamina muscularis mucosae are discussed in relation to the swallowing of
food and submucosal invasion of esophageal cancer.
Correspondence: Dr. Kaoruko Nagai, Department of Oncology Science, Oita Medical
University school of Medicine, 1-1 Idaigaoka, Hasama-machi,Oita-gun, Oita 879-5593,
Japan
Tel: + 81-97-583-5854, Fax: + 81-97-549-4449
E-mail: knagai@oita-med,ac,jp
