Histological remarks of the oviduct and the oviducal gland of Sympterygia acuta Garman, 1877

The elasmobranchs constitute an important resource in Argentinian fishing and they show reproductive characteristics that make them susceptible to the pressure of fishing. In spite of the importance of the resource our knowledge about the species of the Southwestern Atlantic is scarce. In this work we study the microanatomy of the oviduct and the oviducal gland of Sympterygia acuta. The results show a very folded oviduct with mucous and ciliated cells. The oviducal gland depicts the same zonation as other batoids, showing the typical four regions (club, papillary, baffle and terminal). The epithelium lining the glandular lumen is simple columnar with ciliated and glandular cells. The four zones show simple or ramified tubular gland the secretions of which constitute the egg's envelopes. The club and baffle zones are similar to those present in other species. The papillary one depicts a different pattern of secretions that other Rajiformes and the last zone of the gland is characterized by mixed adenomers. The information here exposed constitutes the first report on the microanatomy of the genital tract of S. acuta.     

Presence of two neuropeptides in the fusiform ganglion and reproductive ducts of Octopus vulgaris: FMRFamide and gonadotropin-releasing hormone (GnRH)

We have found evidence of FMRFamide-like and cGnRH-I-like immunoreactivity in the central nervous system (CNS) and in the reproductive ducts of both female and male cephalopod Octopus vulgaris. Cell bodies and fibers were immunolocalized in the fusiform ganglion from which the nerves that reach the female and male reproductive ducts arise. FMRFamide-like and cGnRH-I-like immunoreactive nerve endings were present in the oviduct, and in the oviducal gland of the female and in the seminal vesicle of the male. The GnRH-like peptide from the reproductive ducts has been partially characterized by HPLC. The retention time of the Octopus vulgaris GnRH-like peptide was similar to the retention time of cGnRH-I. Based on these observations we suggest that FMRFamide-like and a novel GnRH-like peptide are involved in the control of reproductive ducts of Octopus vulgaris. One possibility is that the peptides affect gamete transport. Another possibility is that they regulate secretory products such as mucus and mucilaginous substances from the oviducal gland and the seminal vesicle. Our data provide further evidence to support the hypothesis of the existence of a central and peripheral peptidergic control of reproduction of Octopus vulgaris.     

A estradiol-17beta receptor in the reproductive system of the female of Octopus vulgaris: characterization and immunolocalization

In this study, for the first time we have identified an estradiol-17beta receptor (ER) in the reproductive system of the female of Octopus vulgaris. Scatchard analysis revealed that one binding component with high affinity and low capacity for the ligand was present in the cytosol, but not in the nuclear extract of the ovary and the oviduct. A steroid specificity competition assay showed that 3H-estradiol-17beta binding activity showed a preference for estradiol-17beta. DNA-cellulose chromatography confirmed the presence of one 3H-estradiol-17beta binding component. By using antibodies anti ER (578-595), we have localized by Western blotting one band of about 70 kDa. ER immunoreactivity has been localized in the nuclei of the follicle cells of the ovary, in the nuclei of the epithelium lining the proximal portion of the oviduct and in the nuclei, and in the cytoplasm of the inner region of the oviducal gland and in the cytoplasm of the outer region of the oviducal gland. These data, taken together, provide evidence that in Octopus vulgaris the ER has biochemical and immunohistochemical characteristics resembling those of ER in vertebrates.     

The presence of APGWamide in Octopus vulgaris: a possible role in the reproductive behavior

The concerted action of many neuropeptides has been implicated in the nervous control of specific behaviors in many molluscs. In the present study, the presence of amidated tetrapeptide Ala-Pro-Gly-Trp-NH2 (APGWamide) in those lobes that are involved in the control of reproductive behavior in Octopus vulgaris has been investigated. APGWamide immunoreactivity was mainly confined to the posterior olfactory lobule and in the inferior frontal system. These areas are involved in Octopus in the processing of either chemotactile sense or olfaction. From these lobes, immunoreactive fibers reached other lobes of the central nervous system (CNS) which could be indirectly involved in the reproductive behavior. APGWamide immunoreactivity was also present in the glandular cells of the oviducal gland in the female reproductive system. These results constitute the first detailed immunolocalization of APGWamide in cephalopods and open a new insight into the possible effects that both distant and close chemical stimuli can exert on neuropeptidergic circuitries, which may affect the reproductive behavior of cephalopods.     

Immunocytochemical identification of some regulatory peptides (gastrin,gastrin-releasing peptide,neurotensin and vasoactive intestinal polypeptide) in the Harderian gland of the green frog,Rana esculenta

Summary The presence and distribution of gastrin-, gastrin-releasing peptide-, neurotensin-and vasoactive intestinal polypeptide-like immunoreactivity in the Harderian gland ofRana esculenta were studied at different times of the annual cycle. Gastrin-releasing peptide, neurotensin and vasoactive intestinal polypeptide-like substances were found either in the glandular cells, or in the nerve fibers surrounding the glandular acini. Gastrin-like immunoreactivity was confined to the glandular cells. The immunoreactivity varied during the annual cycle, with the greatest concentration being noted during the recovery phase of glandular secretory activity.     

The development of the oviducal gland in the Rajid thornback ray, <Emphasis Type="Italic">Raja clavata</Emphasis>

The reproductive processes of chondrichthyans are complex. Knowledge of the development and maturation of the oviducal gland is vital for understanding the reproductive biology of a species. This study represents the first contribution of this subject for skates. In the oviparous thornback ray, Raja clavata, oviducal gland development begins early in the developing stage with the formation of gland tubules and the distinct lamellae of each zone: club, papillary, baffle and terminal. Oviducal development is complete by the end of the developing stage when the storage and secretion of products is evident within the gland tubules of each zone. Periodic acid-Schiff and alcian blue histological staining showed that the secretory mucous cells of the club and papillary zones produce neutral and sulfated acid mucins. The last row of gland tubules of the papillary zone stains intensely for sulfated acid mucins. The baffle zone, which is responsible for the production of the egg capsule, represented 60–80% of the glandular zone of the oviducal gland. Sperm bundles were observed in the deeper recesses of the baffle zone during the maturation process, and during capsule extrusion, sperm were detected near the lumen. The terminal zone was composed of two types of gland tubules: serous (producing protein fibres) and mucous glands (producing sulfated acid mucins).     

Uterine epithelial-sperm interaction, endometrial cycle and sperm storage in the terminal zone of the oviducal gland in the placental smoothhound, Mustelus canis.

The fate of spermatozoa deposited within the female reproductive tract has been described in the smoothhound, Mustelus canis. Evidence of uterine epithelial-sperm interaction is presented, as well as documentation of sperm storage specifically in the terminal zone of the oviducal gland. Sperm fate is correlated with morphology of the endometrial cycle and specificity of storage in the oviducal gland. The endometrium of M. canis undergoes dramatic tissue remodeling associated with gestation. In females harboring fertilized ova or preimplantation yolk-reliant embryos, the uterine epithelium is simple cuboidal with mucous droplets for lubrication. The presence of the embryo elicits a response from the uterus, which becomes modified for nutrient and respiratory exchange into vascular uterine attachment sites that abut the distal aspect of the yolk sac. Areas of the uterus adjacent to the uterine attachment sites are termed paraplacental sites. Uterine attachment sites are simple squamous while the paraplacental epithelium is simple columnar. Paraplacental cells have basal metachromatic vesicles and a dense array of apical cytoplasmic filaments. Immediately postpartum the uterine attachment sites, now termed uterine or placental scars, begin to remodel to a mucous epithelium for the next gestational cycle. Paraplacental cells slough off the apical filamentous portion, and sperm become embedded in the epithelium. Bundled sperm occur throughout gestation in the terminal zone of the oviducal gland. Sperm are not embedded in the terminal zone epithelium as in the uterus. Following sperm release from the uterus, the paraplacental epithelium reverts to a mucous epithelium for the next reproductive cycle. Fertilization is presumed to occur in the anterior oviduct above the oviducal gland. The physiological mechanisms that mediate sperm-uterus attachment, release, and storage in the terminal zone of the oviducal gland are currently under investigation.     

Progesterone receptor repression by estrogens in rat uterine epithelial cells

Measurements performed using cell lines or animal tissues have shown that the progesterone receptor (PR) can be induced by estrogens. By use of immunohistochemistry we studied the effects of estrogens on the PR levels in the individual cell types of the target organs uterus and breast. In the uteri of rats, ovariectomy induced a decrease in PR immunoreactivity within the myometrium and outer stromal cell layers. In contrast, in the uterine luminal and glandular epithelium and surrounding stromal cell layers the PR immunoreactivity was significantly enhanced. The same picture emerged when intact rats were treated with the pure estrogen receptor antagonist, ZM 182780 (10 mg/kg/d). Treatment of ovariectomized rats with estradiol resulted in high PR levels in the myometrium and stroma cells but low PR immunoreactivity in the epithelial cells. The ER-mediated repression of the PR immunoreactivity was evidently restricted to the uterine epithelium, as we found that in the epithelial cells of the mammary gland and in cells of N-nitrosomethylurea-induced mammary carcinomas the PR expression was induced by estrogens and was blocked by the pure antiestrogen ZM 182780. These results clearly show that in the rat the activated ER induces diverging effects on PR expression in different cell types even within the same organ.     

Immunocytochemical localization of seminal proteins in salivary and lacrimal glands of the rat

Antibodies against 10 different secretory proteins from the accessory sex glands of the male rat were used for immunohistochemical studies of salivary and lacrimal glands from intact and castrated rats, at the light- and electron-microscopic levels. In the parotid gland, secretory acinar cells showed immunoreactivity with antibodies against prostatic binding protein, cystatin-related peptide and acid phosphatase (isoenzyme pI 8.0; 5.6) typical of ventral prostate, and seminal vesicle secretion VI. Western blotting analysis indicated that immunoreactivity against prostatic binding protein was attributable to a subunit, presumably C3. Acid phosphatase pI 5.6 showed a molecular weight of 66 kDa, which is at variance with the prostatic form. Immunoreactivity for secretory transglutaminase, derived from the coagulating gland, was restricted to myoepithelial and stromal cells. In castrated animals, the immunoreactivity of acinar cells was reduced to the background level, whereas stromal transglutaminase immunoreactivity was unaltered. The distribution pattern of immunoreactivity for the proteins mentioned was almost identical in the lacrimal gland. Significant differences were however observed in the immunoreactivity of the inframandibular gland, where serous glandular cells were non-immunoreactive for seminal proteins, with the exception of acid phosphatase isoenzyme pI 8.0. Granules present in the convoluted granular ducts were immunoreactive particularly for acid phosphatase (isoenzyme pI 5.6)but much less for cystatin-related peptide; immunoreactivity was reduced after castration. The straight portion of the inframandibular duct system was immunoreactive for transglutaminase, but no influence of castration was visible. The distribution of immunoreactivity for seminal proteins present in the salivary and lacrimal glands and the pronounced androgen-dependence of their expression point to functional relationships of the respective proteins at both glandular sites.     

Phenylethanolamine N-methyltransferase-(PNMT)-like immunoreactivity in the rat parathyroid gland

A phenylethanolamine N-methyltransferase-(PNMT)-immunoreactivity, present without the other catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH), has been previously detected in the central nervous system and in endocrine cells of the islets of Langerhans and the pituitary intermediate lobe of the rat. In the present study a similar PNMT-like immunoreactivity is demonstrated in the rat parathyroid gland. The immunoreactivity was distinctly localized to the cell periphery, and present in all glandular cells. The thyroid gland was negative. In the parathyroid TH- and DBH-immunoreactivity was seen only in vascular nerve fibers; no glandular cells were stained. The functional significance of the PNMT-like immunoreactivity is not known. The absence of TH- and DBH-immunoreactivity and the low level of adrenaline detected in the parathyroid, and the peripheral localization of the immunoreactivity may indicate an alternative enzyme function or the detection of an immunologically related protein common to pancreatic, pituitary and parathyroid endocrine cells.     

Electron microscopic observations of Orientia tsutsugamushi in salivary gland cells of naturally Infected Leptotrombidium pallidum larvae during feeding

We performed a detailed electron microscopic observation on the escaping process of Orientia tsutsugamushi from the salivary gland cells of naturally infected trombiculid larvae into the acinar lumen of the gland during feeding on mice. In unfed larvae, many O. tsutsugamushi were intermingled with secretory granules in the cytoplasm of the salivary gland cell. O. tsutsugamushi was neither found in the acinar lumen nor observed escaping from the apical surface of the gland cell. In contrast, in the larvae fed on mice, many O. tsutsugamushi were observable in the acinar lumen. They were enveloped with the host glandular cell membrane. In salivary gland cells, secretory granules changed the distribution and accumulated in the apical region. In such cells, the majority of O. tsutsugamushi were found at the base of the cell. Some O. tsutsugamushi were pushing the glandular cell membrane outward in various degrees, showing different stages of escape. These findings suggest that larval feeding induced O. tsutsugamushi escape from salivary gland cells, that the escape was by budding, during which O. tsutsugamushi were enveloped in the host cell membrane, and that O. tsutsugamushi would be injected into the mouse skin as a mixture with mite saliva. The study also revealed the presence of many small vesicles that had the same cell wall structure as O. tsutsugamushi in the cytoplasm of the salivary gland cell. Most of them seemed to be products from degenerated Orientia.     

Immunohistochemical analysis of Bcl-2 and Bax expression in relation to cell turnover and epithelial differentiation markers in the non-lactating human mammary gland epithelium

The expression of the apoptosis-related proteins Bcl-2 and Bax was investigated by immunohistochemistry in the normal non-lactating human mammary gland in relation to cell proliferation and apoptosis. In order to characterize individual Bax/Bcl-2-immunoreactive cells, the epithelial markers cytokeratin 14 and 19 and the macrophage marker CD 68 were used. Secretory-like differentiation of epithelial cells was characterized by histochemistry and lectin staining of surface glycoconjugates. Cell proliferation was exclusively found in glandular epithelial cells with broad contact to the ductular lumen, whereas nuclei with apoptosis-related DNA fragmentation were seen predominantly in basally located glandular epithelial cells and in myoepithelial cells. Weak immunoreactivity for Bcl-2 and Bax was present throughout all epithelia, suggesting a balance between pro- and antiapoptotic effects in the majority of epithelial cells. However, specific cells showed a strong staining for Bax or Bcl-2. The strongly Bcl-2-immunoreactive epithelial cells were not identical with proliferating cells, but they resembled them in configuration and in the luminal intraepithelial position. In contrast, the strongly Bax-positive epithelial cells had no or only a narrow contact to the ductular lumen. The different patterns of Bax/Bcl-2 immunoreactivity in specific glandular epithelial cells suggest that there are also different grades of susceptibility towards apoptotic stimuli in individual glandular epithelial cells. We conclude that specific Bax/Bcl-2 expression patterns could reflect particular cell differentiation states, and that the strongly Bcl-2-positive cells in part could represent epithelial stem cells.     

CGRP-immunoreactive sensory nerve fibers in the submandibular gland of the rat

Summary Indirect immunofluorescence technique was used to study the occurrence and distribution of CGRP immunoreactivity in the submandibular gland of normal rats and after unilateral sensory and sympathetic denervations. In normal rats, CGRP-immunoreactive nerve fibers and nerve trunks were seen around or in close contact with interlobular salivary ducts as well as around small blood vessels of the gland. Occasionally, CGRP-immunoreactive nerve fibers were also detected between or around the acini of the gland.The submandibular ganglia contained CGRP-immunoreactive nerve fibers, but the ganglion cells were not immunoreactive for CGRP. The trigeminal ganglion contained a population of CGRP-immunoreactive, mainly small sized ganglion cells and nerve fibers distributed throughout the ganglion. Unilateral electrocoagulation of the trigeminal nerve caused a significant reduction in the number of immunoreactive nerve fibers in the gland, although some fibers still were present in the ipsilateral glandular tissue. Unilateral superior cervical ganglionectomy caused no detectable effect on the number of CGRP-immunoreactive nerve fibers in the gland.The present results suggest that the rat submandibular gland contains CGRP-immunoreactive nerve fibers both around blood vessels and in glandular secretory elements. Denervation experiments support the view that the majority, but perhaps not all of them originate from the trigeminal ganglion.     

Inflammatory cells as source of tachykinin-induced mucus secretion in chronic bronchitis

Substance P and neurokinin A are regulatory peptides of the tachykinin family that influence many aspects of human airway function in health and diseases such as bronchial asthma or chronic obstructive pulmonary disease (COPD). Tachykinin-induced mucus secretion has been regarded as sensory nerve-dependent so far. We studied the distribution of tachykinin-mRNA and -peptide and its relation to NK-1 subtype-positive cells in human airway glands to assess if tachykinins may also be expressed in inflammatory cells. RT-PCR demonstrated the expression of tachykinin- and NK-1-mRNA in human airway tissues. In situ hybridisation resulted in preprotachykinin (PPT)-A mRNA-signal detection in inflammatory cells which were in close contact to myoepithelial cells of airway glands. NK-1 immunoreactivity was found in myoepithelial cells which were in direct contact to the PPT-A mRNA and tachykinin-positive cells. The present data directly demonstrate the presence of both PPT-A mRNA and tachykinin immunoreactivity in inflammatory airway cells which are in direct contact to NK-1 receptor positive glandular myoepithelium. Our findings indicate that besides neurally released tachykinins, also inflammatory cell-derived tachykinins may lead to glandular secretion via NK-1 receptor stimulation. This points to a major second source of these proinflammatory mediators in chronic inflammatory airway diseases such as COPD or asthma.     

Phenylethanolamine N-methyltransferase-(PNMT)-like immunoreactivity in the rat parathyroid gland

Summary A phenylethanolamine N-methyltransferase-(PNMT)-immunoreactivity, present without the other catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine--hydroxylase (DBH), has been previously detected in the central nervous system and in endocrine cells of the islets of Langerhans and the pituitary intermediate lobe of the rat. In the present study a similar PNMT-like immunoreactivity is demonstrated in the rat parathyroid gland. The immunoreactivity was distinctly localized to the cell periphery, and present in all glandular cells. The thyroid gland was negative. In the parathyroid TH- and DBH-immunoreactivity was seen only in vascular nerve fibers; no glandular cells were stained.The functional significance of the PNMT-like immunoreactivity is not known. The absence of TH- and DBH-immunoreactivity and the low level of adrenaline detected in the parathyroid, and the peripheral localization of the immunoreactivity may indicate an alternative enzyme function or the detection of an immunologically related protein common to pancreatic, pituitary and parathyroid endocrine cells.     

Ultrastructural study of two glandular systems in the proboscidial glandular epithelium of Riseriellus occultus (Nemertea, Heteronemertea)

 Two different types of glandular system in the proboscidial epithelium of Riseriellus occultus have been investigated by transmission electron microscopy. As expected, most of the epithelial cells are glandular in nature. With regard to differences in the ultrastructure of these gland cells and in the formation and morphology of their secretory granules, we have categorized and described four types of gland cell, indicated as G₁, G₂, G₃, and G₄. Each gland cell has a completely intraepithelial body characterized by a prominent nucleus, developed rough endoplasmic reticulum, Golgi complexes, and numerous secretory granules at different stages of maturation. These four types of gland cell appear associated in pairs forming numerous glandular systems of two types (A, B). These glandular systems are restricted to the ventral surface of the proboscis and are scattered irregularly throughout its length. Each glandular system consists of two gland cells of different types. The gland cell necks in each glandular system extend together to the epithelial surface; they protrude onto this and form a papilla where they open in a common area. The epithelial supportive cells adjacent to the glandular systems have long, stout microvilli which have a core of tonofilaments. These tonofilaments gather into dense bundles which pass vertically through the supportive cells and attach to the extracellular matrix underlaying the cells by hemidesmosomes. Moreover, a single sensory process stands close to each papilla. The ultrastructural morphology of the type A glandular systems suggests that they have an adhesive function operating in a similar way to that of the duo-gland adhesive systems in other invertebrate groups, although they are not homologous with these. The spatial arrangement of the secreted products of the type B glandular systems suggests that these may contribute to increasing the grip of the proboscis on the prey. The secretory granules (=pseudocnids) of the type G₃ gland cells are very likely an autapomorphy of the Anopla, providing a character by which the relationships within the Nemertea can be evaluated. Accepted: 9 October 1997     

Are folliculo-stellate cells in the anterior pituitary gland supportive cells or organ-specific stem cells?

Folliculo-stellate cells (FS-cells) in the anterior pituitary gland are star-shaped cells and form tiny follicles. FS-cells are positive for S-100 protein and produce many cytokines or growth factors, such as interleukin-6 (IL-6), leukemia inhibitory factor (LIF), basic fibroblastic growth factor (bFGF) and vascular endothelial cell growth factor (VEGF). Therefore, it is generally accepted that FS-cells regulate endocrine cells through these growth factors. FS-cells also exhibit a phagocytotic activity and are known to work as scavenger cells. In addition to these functions, FS-cells are considered to have some unknown functions. In order to reveal the biological significance of FS-cells in the anterior pituitary gland, we performed a morphological study and obtained some new findings. First, we were interested in the colloid formation in the senescent porcine pituitary gland. We analyzed the colloids and found that clusterin is a major protein in them. We also found that the accumulation of clusterin in the colloids is related to the phagocytotic activity of FS-cells. In our next study, we found that FS-cells have the potential to differentiate into striated muscle cells. From FS-cells show multi-potent cell character and other cytological evidence, we propose that FS-cells are candidate of organ-specific stem cells in the anterior pituitary gland.     

CGRP-immunoreactive sensory nerve fibers in the submandibular gland of the rat

Indirect immunofluorescence technique was used to study the occurrence and distribution of CGRP immunoreactivity in the submandibular gland of normal rats and after unilateral sensory and sympathetic denervations. In normal rats, CGRP-immunoreactive nerve fibers and nerve trunks were seen around or in close contact with interlobular salivary ducts as well as around small blood vessels of the gland. Occasionally, CGRP-immunoreactive nerve fibers were also detected between or around the acini of the gland. The submandibular ganglia contained CGRP-immunoreactive nerve fibers, but the ganglion cells were not immunoreactive for CGRP. The trigeminal ganglion contained a population of CGRP-immunoreactive, mainly small sized ganglion cells and nerve fibers distributed throughout the ganglion. Unilateral electrocoagulation of the trigeminal nerve caused a significant reduction in the number of immunoreactive nerve fibers in the gland, although some fibers still were present in the ipsilateral glandular tissue. Unilateral superior cervical ganglionectomy caused no detectable effect on the number of CGRP-immunoreactive nerve fibers in the gland. The present results suggest that the rat submandibular gland contains CGRP-immunoreactive nerve fibers both around blood vessels and in glandular secretory elements. Denervation experiments support the view that the majority, but perhaps not all of them originate from the trigeminal ganglion.     

Expression of neuronal growth inhibitory factor (metallothionein-III) in the salivary gland

Metallothioneins (MTs) are metal-binding proteins that have been regarded as intrinsic factors for protecting cells and tissues from metal toxicity and oxidants. Among the three major classes of MTs, MT-III is different from other MTs because it has neuronal inhibitory activity and is only expressed in the central nervous system. Recent studies, however, have confirmed that MT-III is also expressed in organs other than the brain. These findings not only indicate that MT-III has a much wider tissue distribution than was originally thought, but also suggest that it might have other unknown activities. In the present study, we examined the human salivary and thyroid glands and demonstrated that the MT-III gene is also expressed in the salivary but not in the thyroid gland. While salivary ducts showed intense immuno-reactivity with anti-MT-III, weak immunoreactivity was observed in acinar cells. This, together with the findings that some neuromodulators (i.e. nerve growth factor, etc.) exist in the salivary gland and that MT-III may participate in the transport in renal tubules, suggest that MT-III may have other functions than cytoprotection in the salivary gland.