Histology and histopathology Vol. 8, nº 2 (1993)

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Open Access
Cellular proliferation andlor differentiation can condition modifications in the expression of AgNORs in rat anterior pituitary cells during growth
(Murcia : F. Hernández, 1993) Carbajo, S.; Carvajal, J.C.; Rodríguez, J.; Carbajo-Pérez, E.
The expression of argyrophilic nucleolar organizer regions (AgNORs) was studied in the anterior lobe of the hypophysis of 1-, 7-, 14-, 28- and 80-day-old rats. Mean area and numbers of AgNORs per nucleus decreased during this period with a simultaneous increase of both nuclear area and mean AgNOR-particle area. Comparison of our data on AgNOR expression with previously reported data on the proliferative activity and cell maturation and differentiation of anterior pituitary cells during a similar period led us to conclude that, at least in our experimental model, variations in the expression of AgNORs are more related to phenomena of cellular maturation than to proliferative activity.
Open Access
Fine structure of the retinal photoreceptors of the tiger salamander (Ambystoma tigrinum)
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 1993) Braekevelt, C. R.
The retinal photoreceptors of the tiger salamander (Ambystoma tigrinum) have been studied by light and electron microscopy in both light- and dark-adaptation. Rods and cones are present in this duplex retina in a ratio of about 20:1. As in other urodele species these photoreceptors are very large cells. The rod outer segment is composed of bi-membranous discs of uniform diameter displaying several very deep incisures. The rod inner segment displays an ellipsoid of mitochondria and a myoid region which changes in diameter during the lighting cycle indicating that rods undergo photomechanical movements. Rod nuclei are located at all levels of the outer nuclear layer and rod spherules are large and display several invaginated and superficial synaptic sites. Cone photoreceptors while large cells are smaller than the rods. They show a smaller tapering outer segment, a large distal ellipsoid of mitochondria and a prominent paraboloid of glycogen but no oil droplet within the inner segment. Judging by the width of the myoid region which remains similar throughout the lighting cycle, cones in this species show no retino-motor responses. Cone nuclei are less electron dense than rods and are also located at all levels of the outer nuclear layer. The cone synaptic pedicle is larger than that of the rods and also shows several invaginated and superficial synaptic sites.
Open Access
Selective immunolabeling of early gestational cytotrophoblast and its neoplastic counterpart by the monoclonal antibody Ber- EP4
(Murcia : F. Hernández, 1993) Babury, R.A.; Moscovic, E.A.
This report presents preliminary observations on the distribution of an epithelial surface antigen in human trophoblastic cells studied with the monoclonal antibody Ber-EP4 by means of an immunoperoxidase technique. Three cases of gestational choriocarcinoma and 20 cases of both villous and extravillous trophoblast, including one complete hydatidiform mole and one exaggerated placental site, were examined with a panel of monoclonal antibodies against epithelial antigen (Ber-EP4), cytokeratin (AE, and AE3), vimentin (VIM), carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA), as well as with polyclonal antibodies against the beta subunit of human chorionic gonadotropin (hCG), human placental lactogen (hPL) and placental alkaline phosphatase (PIAP). While, as anticipated, al1 currently defined trophoblastic cell lines expressed low molecular weight cytokeratin only first trimester cytotrophoblastic cells and their neoplastic counterpart were found to possess the epithelial antigen detected by Ber-EP4. This distinctive property of the cytotrophoblast declined rapidly after eight weeks of gestational age but persisted in second trimester molar tissue and was prominently displayed in choriocarcinoma. By identifying the presence of cytotrophoblastic cell lines in malignancy more reliably than can be achieved with conventional panels of hCG, hPL and PIAP, Ber-EP4 has potential diagnostic utility in gestational trophoblastic disease. Our findings also suggest that the monoclonal anti-CEA antibody may be helpful in distinguishing between syncytiotrophoblastic cells and non-reactive multinucleate cells of the intermediate trophoblast.
Open Access
Pinocytotic vacuoles in human dental pulp capillaries
(Murcia : F. Hernández, 1993) Lyroudia, K.I.; Economou, L.; Manthos, A.; Zervas, P.; Albanou, A.; Foroglou, Ch.
Dental pulp capillaries were studied in human. They were of the cantinuous type, with the exception of a small number which were of the fenestrated type, located in the vicinity of the odontoblasts. A characteristic morphological peculiarity was found in the endothelial cells. In places there was a large quantity of multisized vacuoles. The vacuoles were evidently of pinocytotic origin, and their content was emptied into the extracapillary space. The initiation of their formation was indicated by the creation of cytoplasmic flaps, which could not be characterised as typical pseudopodia, and which in cross sections resembled microvilli. The flaps engulfed a quantity of plasma and then, after bending over, their edge fused with the cell, creating a vacuole. The vacuole, after being moved abluminally, was emptied into the pericapillary area by exocytosis. There was indication that flaps created at the borders of the endothelial cells (flanges) acted likewise, transporting vacuoles through the intercellular spaces. Micropinocytosis, was a distinctly different phenomenon, contributing, to a very small degree, to the intracellular enlargement of the vacuoles. It seems that this vacuolar mechanism of transportation serves an augmented metabolic need of the surrounding tissue.
Open Access
Gastric intestinal metaplasia eleven years after randomized selective proximal vagotomy for peptic ulcer
(Murcia : F. Hernández, 1993) Rubio, C.A.; Emas, S.; Slezak, P.; Nakano, H.; Kalin, B.
The presence of intestinal metaplasia (IM) 11 years after selective proximal vagotomy (SPV), selective proximal vagotomy with pyloroplasty (SPV + PP) and selective vagotomy with pyloroplasty (SV + PP) was investigated in 38 consecutive patients. IM was significantly more frequent in SPV than in SV + PP, SPV + PP or in unoperated controls of matching ages. IM occurred more frequently both at an older age (260 years) in SPV and in a larger number of gastric areas than in the other group of patients. Reports in the literature indicate that vagotomy may increase the risk of gastric carcinoma and that IM inay antedate malignant transformation. It would thus appear that patients previously operated with SPV (without pyloroplasty) having IM, should be the group of patients to be enrolled in endocospical surveillance programs for detection of possible cancer development.
Open Access
Pathological changes in organs of rats chronically exposed to hypoxia. Development of pulmonary lipidosis
(Murcia : F. Hernández, 1993) Wolman, M.; Cervós-Navarro, J.; Sampaolo, S.; Cardesa, Antonio
Rats were exposed to chronic normobaric hypoxia of progressively increasing severity; down to 8% or 7% oxygen concentrations. In addition to loss of weight, pathology revealed congestion, haemorrhages, hypertrophy of the heart involving mainly the right ventricle, thickening of arteries, ischaemic changes in the myocardium and extrarnedullary haematopoiesis in the spleen. Changes not described up until now were: 1) sheets of foam cells in the pulmonary alveoli; 2) foamy and solid storing cells in the spleen; 3) mucoid changes in the atrioventricular valve leaflets; 4) hyperplasia of the juxtaglomerular apparatus; 5) atrophy of the adrenal glomerulosa and hyperplasia of medulla; 6) atrophy of the perifollicular B-cell zone in the spleen; and 7) lipid pigment deposition in various organs. The findings indicate that severe chronic hypoxia induces a significant pulmonary lipidosis similar to that caused by amphiphilic cationic drugs, presumably by inhibiting hydrolytic enzyme activities. The observations are of importante in human hypoxic conditions and open the possibility of their rational treatment.
Open Access
Fine structure of the retinal epithelium of the tiger salamander (Ambystoma tigrinum)
(Murcia : F. Hernández, 1993) Braekevelt, Charlie R.
The retinal pigment epithelium (RPE) of the tiger salamander (Ambystoma tigrinum) consists of a single layer of large squarnous-shaped cells. These RPE cells are but minimally infolded basally (sclerally) but show numerous apical (vitreal) processes that interdigitate with the photoreceptor ceiis. A series of apically-located tight junctions joins the RPE cells to form part of the blood-occular barrier. Internally the RPE nucleus is large, vesicular and flattened. Smooth endoplasmic reticulum predominates in these cells with only occasional small profiles of rough endoplasmic reticulum present. Polysomes and basally-located mitochondria are plentiful. Golgi zones, lipid droplets, lysosome-like bodies and phagosomes of outer segment material are also present. Myeloid bodies which may show ribosomes on their surface are also numerous. The round to oval melanosomes undergo retinomotor movements and in the light-adapted state reach almost to the externa1 limiting membrane. Bmch's membrane or complexus basalis shows a pentalarninate stmcture with the central elastic lamina poorly represented. The choriocapillaris is a single layer of large anastomosing capillaries which are but minimally fenestrated.
Open Access
Epithelial stem cells and their possible role in the development of the normal and diseased human breast
(Murcia : F. Hernández, 1993) Rudland, Philip S.
The developing breasts of peripubescent girls consist of ducts and budded structures, which can subdivide to alveolar budsllobules with advancing maturity and finally to secretory alveoli during pregnancy and lactation. Immunochemical reagents have been used to visualize the three major cell types in histological sections of maturelpregnant breasts, the epithelial cells which line ductslductules, the smooth muscle-like myoepithelial cells and the casein-secretory alveolar cells. Ductal budded structures contain basal cells intermediate in immunocytochemical staining characteristics between epithelial and myoepithelial cells. Immortalization of primary epithelial cultures of normal breasts by simian virus 40 yields epithelial cell lines that can differentiate to myoepithelial-like and to secretory alveolar-like cells; similar cell types are identifiable in primary cultures. Immunocytochemical staining shows that both hyperplastic and neoplastic benign lesions contain myoepithelial-like cells, and, under suitable hormonal conditions, alveolar-like cells, but invasive carcinomas contain neither differentiated cell type. Primary cell cultures of benign hyperplastic and neoplastic lesions contain epithelial, myoepitheliallike and presumptive alveolar-like cells whilst malignant cell fractions of invasive carcinomas contain only epithelial cells. Spontaneously-immortalized epithelial cell lines from hyperplastic benign breast disease can generate myoepithelial-like and alveolar-like cells, whilst standard epithelial cell lines from pleural effusions and novel epithelial cell lines from primaries of invasive carcinomas fail to differentiate to either cell type. It is suggested that epitheliallintermediate stem cells exist in a basal position predominantly in terminal structures of growing breasts, and that they are the major cell type involved in benign hyperplastic, benign neoplastic and malignant breast diseases. The acquisition of the malignant phenotype is associated with the carcinoma cells having a greatly impaired ability to differentiate to myoepithelial and to alveolar cells.
Open Access
Effects of bombesin and neuromedin-B on the proliferative activity of the rat adrenal cortex
(Murcia : F. Hernández, 1993) Markowska, A.; Nussdorfer, G.G.; Malendowicz, L.K.
Bombesin (BM) and neuromedin-B (NMB) exert similar biological effects, acting via two functionally distinct BM-receptor subtypes. The present study aimed to investigate whether BM and NMB stimulate the proliferation of rat adrenocortical cells and to compare their mode of action. Adult female rats were treated with a single subcutaneous dose of 3 pg BM or NMB. Adrenocortical proliferative activity was assessed by the metaphase-arrest technique. BM administration resulted in a marked increase in the number of metaphases in zona glomerulosa (ZG) and zona fasciculata (ZF), and in the entire cortex. This increase appeared 24 h after injection in the ZG, and after 48 h in the ZF. NMB adrninistration, on the other hand, caused a prompt increase in the number of metaphases in the ZG and entire cortex at 12 h, followed by a subsequent drop below the control leve1 at 24 and 48 h of experiment. These findings indicate that BM and NMB enhance the proliferative activity of rat adrenocortical cells acting via different receptors or different mediators.
Open Access
Morphological properties of human thyroid tumor cells in collagen gel culture and metastatic or invasive ability
(Murcia : F. Hernández, 1993) Nishida, S.; Hosokawa, K.; Kusunoki, T.; Koezuka, M.; Akai, F.; Nakano, T.; Funasaka, K.; yoshioka, Y.; Murata, K.; Hashimoto, S.; Tomura, T.T.
Using normal human thyroid cells and tumor cells, the reconstruction of various diseased cells in collagen gel as well as the relationship between the morphology of colonies in collagen-embedded culture and the biological behavior (benignity, malignancy, metastasis, and invasion) of the original tumors were studied. In collagen gel culture, normal thyroid cells reorganized follicle-like constructions, and follicular adenoma cells showed in vivo-like constructions. However, two different types of colonies were observed in cultures of cells from papillary carcinomas. One was the branching type with many outgrowths projecting to three dimensions and the other was the spherical type without any outgrowths. These spherical colonies were observed in al1 cases of papillary carcinoma, but varied from one case to another. Metastasis and invasion were detected during pathological examination in cases with a high ratio of spherical colonies. Our results indicate that cells from highly metastatic and invasive thyroid cancer form spherical colonies in the collagen gel culture, and that this collagen culture is a useful method for studying the heterogeneity of tumor cells as well as the metastasis and invasive ability of tumor cells in vitro.
Open Access
Effects of chronic ethanol administration on the serotonin-producing cells in rat gastric antral and duodenal mucosa
(Murcia : F. Hernández, 1993) Todorovic, V.; Koko, V.; Varagic, J.; Lackovic, V.; Vuzevski, V.D.; Milin, J.
The present study describes our observations on optical and ultrastructural features of serotonincontaining cells in the rat antral and upper duodenal mucosa, utilizing optic morphometric measurements in a model of experimental chronic alcoholism of rat in which nutrition was well controlled. Male Wistar rats were given ethanol to provide 23 per cent of the total calories, while starch replaced ethanol isocalorically in controls. Twenty-five per cent of the calories were provided by protein in both groups. Blood levels of serotonin were significantly raised after chronic ethanol feeding (0.05910.06 vs. 0.15910.012 pglml, p<0.01). Decrease in the number of immunohistochemicallydetectable serotonin-containing cells was found in the pyloric gland mucosal area specimens of the chronically ethanol-treated rats (68.915.2 vs 43.313.0; p<0.001). The immunohistologically-evaluated number of the same cells in the duodenal mucosa specimens was significantly decreased by alcohol feeding. Although total villi and crypt count per whole circular section, and the number of crypts per villus were not significantly changed either in control animals or in chronically ethanol-fed rats, decreased number of these cells per whole circular section (289121.6 vs. 183f 10.5; p
Open Access
Lectin histochemistry of salivary glands in the Gian t An t-eater (Myrmecophaga tridactyla)
(Murcia : F. Hernández, 1993) Meyer, W.; Beyer, C.; Wissdorf, H.
The submandibular and buccal glands of the Giant Ant-eater (Myrmecophaga tridactyla) have been studied by means of a series of carbohydrate histochemical methods, including a broad spectrum of PO-lectin procedures. The seromucous cells (Gl. submandibularis) and mucous cells (Gl. buccalis) of the glandular acini, as well as the secretion in the excretory duct system exhibited very strong to strong reactions for neutral and acidic glycocongugates. The serous cells of the buccal glands and the excretory duct cells reacted rather weakly. The different controls applied particularly emphasized that sialoglycoconjugates are the predominant ingredients of the saliva secreted. Lectin histochemical differentiation demonstrated a varying pattern of saccharide residues in these substances. In the submandibular glands the glycocongujates (mostly proteoglycans) of the seromucous cells and the luminal secretion normally contained terminal B-galactose and minor contents of terminal a-N-acetylglucosamine. After sialidase digestion this cell type exhibited distinct amounts of sialic acid-B-galactose and sialic acid-a-N-acetylgalactosamine. Sialic acid was also clearly present in the tough interlobular connective tissue. The buccal glands showed a similar distribution of saccharide residues in the mucous cells. In the serous cells, however, acidic glycoproteins with sialyl residues were observed, also containing terminal a-D-mannosyl, a-N-acetylgalactosaminyl, and B-D-galactosyl residues. The cells of the excretory duct system of both gland types reacted weakly to moderately for terminal sugar residues (Nacetyl- D-glucosamine, N-acetyl-D-galactosamine, B-Dgalactose). The results obtained are discussed in view of the specific feeding mode of the Giant Ant-eater, whereby high contents of sialoglycoconjugates (proteoglycans, glycoproteins) produced by the salivary glands warrant for the main function of the non-sticky saliva; i.e., to act as an effective lubricant during tongue movement.
Open Access
Tumor-infiltrating lymphocytes expressing IOT-10 marker. An immunohistochemical study of a series of 185 brain tumors
(Murcia : F. Hernández, 1993) Zurita, M.; Vaquero, J.; Coca, S.; Oya, S.; García, N .
The presence of IOT-10-positive lymphocytes among the tumor-infiltrating-lymphocyte (TIL) population was studied in a series of 185 brain tumors. In most of the tumors, IOT-10-positive lymphocytes were identified, but generally they were scarce and masked among the tumor cells, suggesting that NK-cells exercise a poor participation in the tissular response against brain tumors. Isolated tumor cells showing IOT- 10-positivity were found in low-grade astrocytomas, neurinomas and medulloblastomas. IOT- 10-positivity on both tumor neuropil and tumor cells was considered a characteristic finding in oligodendrogliomas. The number of IOT- 10-positive NK-cells in brain metastases and in cerebellar hemangioblastomas was comparatively greater than in other types of brain tumor. Since in brain metastases, the presence of IOT-10-positive NK-cells can be related to the tissular response to an extracerebral malignancy, their considerable presence in cerebellar hemangioblastomas is an enigmatic finding that desemes further attention.
Open Access
In vitro antigen trapping by gil1 cells of the rainbow trout: an immunohistochemical study
(Murcia : F. Hernández, 1993) Torroba, M.; Anderson, D.P.; Dixon, O.W.; Casares, F.; Varas, A.; Alonso, L.M.
An in vitro assay was used to study the involvement of gill cells in the trapping and processing of particulate antigens. Gills were routinely processed for light microscopy after being placed in medium containing either Yersinia ruckeri O-antigen-labelled fluorescent beads, unlabelled fluorescent beads, Y. ruckeri O-antigen or formalin-killed Y. ruckeri, for 0, 30 S, 1, 5 and 30 min. Y. ruckeri formalin-killed cells, Y. ruckeri O-antigen and fluorescent beads labelled with Y. ruckeri O-antigen were taken in by gill epithelial cells as soon as 30 S after administration. In contrast, unlabelled fluorescent beads adhered to the epithelial cell membranes, but did not occur inside the gill cells. These results are discussed principally in relationship with the specificity of antigen trapping.
Open Access
Reverse lectin histochemistry: Design and application of glycoligands for detection of cell and tissue lectins
(Murcia : F. Hernández, 1993) Gabius, H.J.; Gabius, S.; Zemlyanukhina, T.V.; Bovin, N.V.; Brinck, U.; Danguy, A.; Joshi, S.S.; Kaiser, K.; Schottelius, J.; Sinowatz, F.; Tietze, L.F.; Vidal-Vanaclocha, F.; Zanetta, J.P.
Plant and invertebrate lectins are valuable cyto- and histological tools for the localization of defined carbohydrate determinants. The welldocumented ubiquitous occurrence of sugar receptors encourages functional considerations. Undoubtedly, analysis of the presence of vertebrate lectins in tissues and cells is required to answer the pertinent and tempting question on the physiological relevance of protein (1ectin)-carbohydrate recognition in situ. Carrierimmobilized glycoligands, derived from custom-made chemical synthesis, enable the visualization of respective binding sites. Histochemically inert proteins or synthetic polymers with appropriate functional groups are suitable carrier molecules for essential incorporation of ligand and label. The resulting neoglycoconjugates can track down tissue receptors that are neither impaired by fixation procedures nor blocked by endogenous highaffinity ligands. Lectins, especially the receptors of the tissue under investigation (endogenous lectins), and appropriately tailored immobilized glycoligands or lectin-specific antibodies (when available) are complementary tools to test the attractive hypothesis that diverse, functionally relevant glycobiological processes within or between cells are operative. Concomitant evaluation of both sides of lectin histochemistry, namelylectins as tools and lectins as functionally important molecules in situ, will indubitably render desired progress amenable in our often still fragmentary understanding of the importance of tissue lectin and glycoconjugate expression and its regulation.
Open Access
Histochemical localization of glycosaminoglycans in the omasal papillae of sheep
(Murcia : F. Hernández, 1993) Yamamoto, Y.; Kitamura, N.; Yamada, J.; Yamashita, T.
Histochemical localization of the glycosaminoglycans in the omasal laminae were examined at light and electron microscopic levels. The core region of the omasal papillae was stained strongly with alcian blue at pH 2.5 and 1.0. The staining was degraded moderately and completely when tissue sections were pretreated with mild and active methylation, respectively. Alcianophilia was moderately decreased with saponification. Furthermore, enzymatic digestion procedures showed that these alcianophilic substances contained a large amount of hyaluronic acid and chondroitin sulphate. Ultrastructurally, a spider weblike structure was widely distributed among the spindleshaped fibroblast-like cells and fibrous networks of collagen and elastin. These results suggest that the core region of the omasal papillae not only acts as a physical buffer resisting the local pressure from the lumen, but may also influence material transport through the omasal mucosa.
Open Access
A quantitative description of the insulin-induced ultrastructural changes in newborn rat hepatocytes
(Murcia : F. Hernández, 1993) Maintas, D.B.; Kotoulas, Othon B.; Kotoulas, Angeliki O.
The effects of insulin on the ultrastructure of newborn rat hepatocytes were systernatically quantified at satisfactory statistical significance. Insulin prevented the normal postnatal increase in the total volume of lysosomes and the breakdown of glycogen inside these organelles. The lysosomal glycogen-hydrolysing enzyme, acid alpha 1,4 glucosidase was inhibited by the hormone. Insulin also prevented the normal postnatal increase in the total volume of peroxisomes, especially of the crystalloid core-devoid type. The hormone produced an increase in the area of cell membrane, due to the forrnation of many irregular folds of the cell surface. These results constitute good evidence for participation of lysosomes and peroxisomes in the overall glycogen degradation and or gluconeogenesis in the newborn rat hepatocytes.
Open Access
Characterization of the glycoconjugate sugar residues in developing chick esophageal epithelium
(Murcia : F. Hernández, 1993) Gheri, G.; Gheri Bryk, S.; Sgambati, E.; Gulisano, M.
The development of the esophagus in the chick embryo is characterized by remarkable morphological changes especially at the level of the epithelium. Using horseradish peroxidase-conjugated lectins (DBA, PNA, SBA, WGA, ConA, LTA, UEAI) we have studied, at the level of the esophagus of chick embryos from the 8th to the 21st day of incubation and of 1- and 2-day-old chicken, the evolution of the saccharidic moieties of glycoconjugates, which precedes andlor is concomitant with the epithelial morphological transformations. We have found differences in content and cellular distribution of oligosaccharides during the histogenetic processes which characterize the lining and glandular epithelium. Before the appearance of cilia and mucus secretion at the bathyprismatic epithelial cells, the sugar residues D-galactose-(B 133)-N-acetyl-Dgalactosamine, B-N-acetyl-D-galactosamine and a-Lfucose were detected only at the luminal cell surface. These oligosaccharides were probably involved in giving rise to the polarization of the esophageal epithelial cells. The esophageal gland mucus was first characterized by the presence of a-L-fucose and afterwards also by the presence of D-galactose-(Bl33)-N-acetyl-Dgalactosamine, D-glucosamine and sialic acid.
Open Access
Lectin histochemical study on the kidney of normal and streptozotocin-induced diabetic hamsters
(Murcia : F. Hernández, 1993) Aguirre, J.I.; Han, J.S.; Itagaki, S.; Doi, K.
Lectin histochernical characteristics of the kidney of normal and streptozotocin (SZ)-induced diabetic APA harnsters were investigated. Paraffin sections of the kidney of animals killed at 1 and 3 rnonths after SZ-injection were stained with the following 10 lectins: PNA, BPA, DBA, SBA, GSA-1, GSA-11, MPA, WGA, UEA-1 and Con A. Renal lectin binding characteristics of normal APA harnsters differed in sorne aspects from those in other species reported previously. In the kidney of SZ-induced diabetic APA hamsters, binding activities of sorne lectins increased in the affected Bowman's capsules and glorneruli as well as in degenerated epithelial cells of uriniferous tubules. Among thern, GSA-11 in particular exhibited strong binding activity to the degenerated epithelial cells of Bowman's capsules, dista1 convoluted tubules and collecting ducts.
Open Access
An immunohistochemical survey of peptide-containing nerves in the copulatory apparatus of several male birds
(Murcia : F. Hernández, 1993) Kitamura, N.; Yamada, J.; Hayashi, Yoshihiro; Nishida, T.
Distribution of peptide-containing nerves in male copulatory apparatus as well as rectal and cloacal ganglia were examined immunohistochemically in cock, guinea fowl, duck and muscovy duck. Neurofilament protein-immunoreactive nerves were also examined to investigate general distribution of nerves. Substance P (SP)-, vasoactive intestinal polypeptide (VIP)-, calcitonin gene-related peptide (CGRP)-, and neuropeptide Y (NPY)-immunoreactive (IR) nerves were detected in al1 four species of birds whereas leucine enkephalin (LENK)-IR nerves were detected only in duck and muscovy duck. In the rectal and cloacal ganglia, peptide-IR nerves were detected in varying degrees of abundance. Most noticeable distribution was found in the vascular body, where SP-IR nerve fibres were more abundant in duck and muscovy duck, VIP-IR fibres in muscovy duck and CGRP-IR fibres in duck, than in other regions and other species, respectively. A few peptide-IR nerve fibres were detected in other cloacal regions, although a peculiar pattern in distribution unique to a certain region could be not found. The present results suggest that the peptidecontaining nerves participate in the regulation of tumescence, erection and detumescence of male copulatory apparatus of birds and their regulatory mechanisms are different depending on the species.