Potential role of orexin A binding the receptor 1 for orexins in normal and cryptorchid dogs.

BACKGROUND: Cryptorchidism is one of the most common birth disorders of the male reproductive system identified in dogs and other mammals. This condition is characterised by the absence of one (unilateral) or both (bilateral) gonads from the scrotum. The peptides orexin A (OxA) and B (OxB) were obtained by post-transcriptional proteolytic cleavage of a precursor molecule, called prepro-orexin. These substances bind two types of G-coupled receptors called receptor 1 (OX1R) and 2 (OX2R) for orexins. OX1R is specific to OxA while OX2R binds the two peptides with equal affinity. Orexins modulate a great variety of body functions, such as the reproductive mechanism. The purpose of the present research was to study the presence of OxA and its receptor 1 and their possible involvement in the canine testis under healthy and pathological conditions. METHODS: This study was performed using adult male normal dogs and male dogs affected by unilateral cryptorchidism. Tissue samples were collected from testes and were divided into three groups: normal, contralateral and cryptic. The samples were used for immunohistochemistry, Western blot and in vitro tests for testosterone evaluation in normal and pathological conditions. RESULTS: OxA-immunoreactivity (IR) was described in interstitial Leydig cells of the normal gonad, and Leydig, Sertoli cells and gonocytes in the cryptic gonad. In the normal testis, OX1R-IR was described in Leydig cells, in pachytene and second spermatocytes and in immature and mature spermatids throughout the stages of the germ developing cycle of the male gonad. In the cryptic testis OX1R-IR was distributed in Leydig and Sertoli cells. The presence of prepro-orexin and OX1R was demonstrated by Western blot analysis. The incubation of fresh testis slices with OxA caused the stimulation of testosterone synthesis in the normal and cryptic gonad while the steroidogenic OxA-induced effect was cancelled by adding the selective OX1R antagonist SB-408124. CONCLUSIONS: These results led us to hypothesise that OxA binding OX1R might be involved in the modulation of spermatogenesis and steroidogenesis in canine testis in healthy and pathological conditions.

Expression of orexin B and its receptor 2 in rat testis.

The peptides orexin A (OxA) and orexin B (OxB) deriving from a common precursor molecule, prepro-orexin, by proteolytic cleavage, bind the two G-coupled OX1 and OX2 receptors. While OX1 selectively binds OxA, OX2 shows similar affinity for both orexins. Firstly discovered in the hypothalamus, orexins and their receptors have been found in other brain regions as well as in peripheral tissues of mammals, thus resulting involved in the regulation of a broad variety of physiological functions. While the functional localization of OxA and OX1 in the mammalian genital tract has been already described, the expression of OxB and OX2 and their potential role in the reproductive functions remain to be explored. Here, we investigated the presence of OxB and OX2 in the rat testis by immunohistochemical and biochemical analyses. The results definitely demonstrated the localization of OxB and OX2 in pachytene and second spermatocytes as well as in spermatids at all stages of the cycle of the seminiferous epithelium. The expression of both OX2 mRNA and protein in the rat testis was also established by RT-PCR and Western blotting, respectively. The analysis of the molecular mechanism of action of OxB in the rat testis showed that OxB, in contrast with OxA, is unable to promote steroidogenesis. These results translate into the regulation of diverse biological actions by OxA and OxB in the male gonad.

Chronic maternal morphine alters calbindin D-28k expression pattern in postnatal mouse brain.

The distribution pattern of calbindin (CB)-D28k-expressing neurons results to be altered in several brain regions of chronic morphine exposed adult mice. In this study, the influence of chronic maternal exposure to morphine on the distribution pattern of CB-D28k-expressing neurons in the brain of mouse offspring was investigated. Females of CD-1 mice were daily administered with saline or morphine for 7 days before mating, during the whole gestation period, and until 21 day post-partum. Their offspring were sacrificed on postnatal day 18, and the brains were examined by histology using cresyl violet and by immunohistochemistry using a rabbit polyclonal anti-CB-D28k antibody. Histology revealed no significant differences in the distribution pattern and the number of neurons between the offspring forebrain of the control group of mice and the two groups of mice treated with different doses of morphine. However, immunohistochemical analysis revealed that the number of CB-D28k-immunoreactive neurons remarkably decreased in the cingulate cortex, in the layers II-IV of the parietal cortex and in all regions of the hippocampus, while it increased in the layers V-VI of the parietal cortex and in the subicular region of the offspring brain of morphine treated mice. Overall, our findings demonstrate that maternal exposure to morphine alters the pattern of CB-D28k-expressing neuron pattern in specific regions of murine developing brain, in a layer- and dose-dependent way, thus suggesting that these alterations might represent a mechanism by which morphine modifies the functional aspects of developing brain.

Expression and potential role of the peptide orexin-A in prostate cancer.

The peptides orexin-A and orexin-B and their G protein-coupled OX1 and OX2 receptors are involved in multiple physiological processes in the central nervous system and peripheral organs. Altered expression or signaling dysregulation of orexins and their receptors have been associated with a wide range of human diseases including narcolepsy, obesity, drug addiction, and cancer. Although orexin-A, its precursor molecule prepro-orexin and OX1 receptor have been detected in the human normal and hyperplastic prostate tissues, their expression and function in the prostate cancer (PCa) remains to be addressed. Here, we demonstrate for the first time the immunohistochemical localization of orexin-A in human PCa specimens, and the expression of prepro-orexin and OX1 receptor at both protein and mRNA levels in these tissues. Orexin-A administration to the human androgen-dependent prostate carcinoma cells LNCaP up-regulates OX1 receptor expression resulting in a decrease of cell survival. Noteworthy, nanomolar concentrations of the peptide counteract the testosterone-induced nuclear translocation of the androgen receptor in the cells: the orexin-A action is prevented by the addition of the OX1 receptor antagonist SB-408124 to the test system. These findings indicate that orexin-A/OX1 receptor interaction interferes with the activity of the androgen receptor which regulates PCa onset and progression, thus suggesting that orexin-A and its receptor might represent novel therapeutic targets to challenge this aggressive cancer.

Immunolocalization of Two Neurotrophins, NGF and BDNF, in the Pancreas of the South American Sea Lion Otaria flavescens and Bottlenose Dolphin Tursiops truncatus.

In this study, we have investigated the immunolocalization of NGF (Nerve Growth Factor) and BDNF (Brain-Derived Neurotrophic Factor) in the pancreas of two species of marine mammals: Tursiops truncatus (common bottlenose dolphin), belonging to the order of the Artiodactyla, and Otaria flavescens (South American sea lion), belonging to the order of the Carnivora. Our results demonstrated a significant presence of NGF and BDNF in the pancreas of both species with a wide distribution pattern observed in the exocrine and endocrine components. We identified some differences that can be attributed to the different feeding habits of the two species, which possess a different morphological organization of the digestive system. Altogether, these preliminary observations open new perspectives on the function of neurotrophins and the adaptive mechanisms of marine mammals in the aquatic environment, suggesting potential parallels between the physiology of marine and terrestrial mammals.

A Comparative Analysis of Orexins in the Physio-Pathological Processes of the Male Genital Tract: New Challenges? A Review.

Orexins A (OXA) and B (OXB) and their specific receptors, receptor 1 (OX1R) and 2 (OX2R) for orexins, are hypothalamic peptides involved in orchestrating several functions in the central nervous system and peripheral organs, including sleep, excitement, nutrition, reward, circadian rhythm, anxiety, cognition, and reproduction. The aim of this narrative review is, in particular, to speculate the role of orexins in the male genital tract of animal species and human beings. The experimental evidence collected in recent years assumed that in the testes of the animal species here described, orexins are directly involved in steroidogenesis and spermatogenesis regulation. In the epididymis, these peptides are locally synthesized, thus suggesting their role governing the fertilizing capability of the immature male gamete. In addition to playing a physiological role, orexins are involved in numerous inflammatory and/or neoplastic pathologies too. The expression of the orexinergic system in prostate cancer suggests that they might play a potential therapeutic function. Overall, the future directions of this literature review allow us to hypothesize a role of the orexinergic complex not only as a marker for the diagnosis of certain tumors affecting the male genital tract but also for the treatment of hypo/infertility condition.

Hepatitis E and Potential Public Health Implications from a One-Health Perspective: Special Focus on the European Wild Boar (Sus scrofa).

The hepatitis E virus (HEV) has become increasingly important in recent years in terms of risk for public health, as the main causative agent of acute viral hepatitis. It is a foodborne disease transmitted to humans through the consumption of contaminated water or contaminated food. Human-to-human transmission is sporadic and is linked to transfusions or transplants. The main reservoirs of the hepatitis E virus are domestic pigs and wild boars, although, compared to pigs, wild boars represent a lesser source of risk since their population is smaller and the consumption of derived products is more limited. These peculiarities often make the role of the wild boar reservoir in the spread of the disease underestimated. As a public health problem that involves several animal species and humans, the management of the disease requires an interdisciplinary approach, and the concept of "One Health" must be addressed. In this direction, the present review intends to analyze viral hepatitis E, with a particular focus on wild boar. For this purpose, literature data have been collected from different scientific search engines: PubMed, MEDLINE, and Google scholar, and several keywords such as "HEV epidemiology", "Extrahepatic manifestations of Hepatitis E", and "HEV infection control measures", among others, have been used. In the first part, the manuscript provides general information on the disease, such as epidemiology, transmission methods, clinical manifestations and implications on public health. In the second part, it addresses in more detail the role of wild boar as a reservoir and the implications related to the virus epidemiology. The document will be useful to all those who intend to analyze this infectious disease from a "One-Health" perspective.

Neuronal control of the vagina in vertebrates: A review.

BACKGROUND: At present, there is an increased interest in the vaginal microbiome. It is believed that microbes play equally important roles in the vagina, including the modulation of neuronal pathways, as in the gut. However, in man as well as in animals, the vagina is the least well-studied part of the female reproductive system. The vagina, a fibromuscular tract, having two main functions, i.e., childbirth and sexual intercourse, is mainly innervated by the pudendal nerve and the pelvic splanchnic nerves (the uterovaginal nerve plexus) containing sympathetic, parasympathetic and nociceptive nerve fibers. Innervation density in the vaginal wall undergoes significant remodeling due to hormonally mediated physiological activity. Knowledge about expression and function of neuropeptides and neurotransmitters in the vaginal fibers is incomplete or not established. Most research concerning the neuroregulation of the vagina and the function and expression of neuropeptides and neurotransmitters, is performed in several vertebrate species, including large farm animals, rodents, domestic fowl and lizards. METHODS: This review summarizes, on a bibliographic basis, the current knowledge on vaginal innervation and function of neuropeptides and neurotransmitters expressed in vaginal nerve fibers in several vertebrate species, including humans. The presence and role played by the local microbioma is also explored. CONCLUSION: A thorough knowledge of the vaginal innervation is necessary to unravel the putative communication of the vaginal microbiome and vaginal nerve fibers, but also to understand the effects of vaginal pathologies and of administered drugs on the neuroregulation of the vagina.

Orexins and Prostate Cancer: State of the Art and Potential Experimental and Therapeutic Perspectives.

Prostate cancer (PCa) is the second most common cancer in humans. Peptides have recently been used as targeted therapeutics in cancers, due to their extensive multi-functional applications. Two hypothalamic peptides, orexins A (OXA) and B (OXB) and their specific receptors, orexin receptor 1 (OX1R) and 2 (OX2R), orchestrate several biological processes in the central nervous system and peripheral organs. However, in addition to their role in physiological responses, orexins are involved in numerous inflammatory and/or neoplastic pathologies. The presence and expression of orexins in different cancer models, including prostate cancer, and their role in inducing pro- or anti-apoptotic responses in tumor cell lines, suggest that the orexinergic system might have potential therapeutic action or function as a diagnostic marker in PCa. In addition to the traditional animal models for studying human PCa, the canine model might also serve as an additional tool, due to its clinical similarities with human prostate cancer.

Human-Animal Interaction in Animal-Assisted Interventions (AAI)s: Zoonosis Risks, Benefits, and Future Directions-A One Health Approach.

Animal-assisted interventions (AAI)s represent the expression of integrated medicine, according to the One Health approach. Actually, animal-assisted therapies and animal-assisted activities are implemented in hospitals, rehabilitation centers, etc. The efficacy of AAIs is based on interspecific interactions and would be impacted by different factors, such as the characters of both the animal and the handler, a suitable selection of animal species, an appropriate animal educational protocol, the relationship between the handler and the animal, and mutual relationship among the animal, the patients, and members of the working team. AAIs produce many advantages for the patients but could expose them to zoonotic-pathogens transmission. Therefore, positive animal welfare, as preventative medicine to avoid incidents or transmission of zoonosis, is a relevant aspect with implications for human and animal health and wellbeing. This review aims to summarize the current published knowledge regarding the occurrence of pathogens in AAIs and to discuss their relevance in light of health and safety in AAIs participants. In addition, this review will contribute to defining the state of the art of AAIs through a careful benefits/challenges analysis and offers discussion points on the possible future developments according to the One Health approach.

Does Orexin B-Binding Receptor 2 for Orexins Regulate Testicular and Epididymal Functions in Normal and Cryptorchid Dogs?

Orexins A (OXA) and B (OXB) and the receptors 1 (OX1R) and 2 (OX2R) for orexins are hypothalamic peptides found in several mammalian organs and participated to the control of a wide assortment of physiological and pathological functions. The distribution of OXA and OX1R has been extensively studied in the male gonad of mammals. Here, we examined the expression and localization of OXB and OX2R as well as their possible involvement in the regulation of testicular and epididymal functions, in healthy and cryptorchid dogs, employing some techniques such as immunohistochemistry, Western blotting, and real-time RT-PCR. In vitro tests were also carried out for evaluating the steroidogenic effect of OXB. OXB and OX2R were expressed in spermatocytes, spermatids, and Leydig cells in normal testis. Their localization was restricted to Sertoli and Leydig cells in cryptorchid conditions. OXB was found to be localized in all tracts of both normal and cryptorchid epididymis, whereas OX2R was found only in the caput. Because the small molecular weight of the peptides OXA and OXB, the expression of their precursor prepro-orexin (PPO), OX1R, and OX2R proteins and mRNAs were investigated by means of Western blot and real-time RT-PCR analyses, respectively, in all tested groups of. In particular, the mRNA level expression of all three genes was higher in cryptorchid dogs than in normal ones. In vitro tests demonstrated that OXB-by binding OX2R-is not involved in testicular steroidogenic processes. Therefore, the findings of this study might be the basis for further functional and molecular studies addressing the possible biochemical effects of OXB and OX2R in normal and pathological conditions of the male reproductive system.

The effect of inflammation on the expression and distribution of the MAS-related gene receptors MrgE and MrgF in the murine ileum.

The MAS-related gene (Mrg) receptor MrgE has been suggested to be expressed at all tissue levels involved in pain sensation and to influence the expression of another Mrg receptor, MrgF. Given the knowledge on the role of the enteric nervous system (ENS) in sensation, and the plasticity of enteric neurons during intestinal inflammation, it can be hypothesized that MrgE is expressed in enteric neurons, and that MrgE and MrgF change expression in intestinal inflammatory conditions. Therefore, we aimed to reveal the expression details of MrgE and MrgF in the murine ileum in normal and inflamed conditions. Using reverse transcriptase-PCR, quantitative-PCR and immunohistochemistry, we compared the ileum of non-inflamed control mice with that of two models of intestinal inflammation, i.e. intestinal schistosomiasis and chemically induced ileitis. MrgE and MrgF mRNAs were detected in control and inflamed conditions. MrgE and MrgF mRNAs showed a trend towards downregulation during intestinal schistosomiasis and a significant reduction during ileitis. MrgE and MrgF receptors were expressed in distinct enteric neuronal subpopulations, such as the sensory, secretomotor and vasodilator neurons, and in nerve fibres in the tunica muscularis and lamina propria of control and inflamed ileum. Only a minor proportion of enteric neurons co-expressed MrgE and MrgF. The number of enteric neurons expressing MrgE and MrgF receptors was significantly reduced during intestinal schistosomiasis and ileitis. This is the first report on the expression of MrgE and MrgF in the ENS in (patho)physiological conditions. The expression of MrgE and MrgF in enteric neurons was negatively affected by inflammation.

Do Animals Play a Role in the Transmission of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2)? A Commentary.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) belongs to the Beta-coronavirus genus. It is 96.2% homologous to bat CoV RaTG13 and 88% homologous to two bat SARS-like coronaviruses. SARS-CoV-2 is the infectious agent responsible for the coronavirus disease (COVID-19), which was first reported in the Hubei province of Wuhan, China, at the beginning of December 2019. Human transmission from COVID-19 patients or incubation carriers occurs via coughing, sneezing, speaking, discharge from the nose, or fecal contamination. Various strains of the virus have been reported around the world, with different virulence and behavior. In addition, SARS-CoV-2 shares certain epitopes with some taxonomically related viruses, with tropism for the most common synanthropic animals. By elucidating the immunological properties of the circulating SARS-CoV-2, a partial protection due to human-animal interactions could be supposed in some situations. In addition, differential epitopes could be used for the differential diagnosis of SARS-CoV-2 infection. There have been cases of transmission from people with COVID-19 to pets such as cats and dogs. In addition, wild felines were infected. All These animals were either asymptomatic or mildly symptomatic and recovered spontaneously. Experimental studies showed cats and ferrets to be more susceptible to COVID-19. COVID-19 positive dogs and felines do not transmit the infection to humans. In contrast, minks at farms were severely infected from people with COVID-19. A SARS-Cov-2 variant in the Danish farmed mink that had been previously infected by COVID-19 positive workers, spread to mink workers causing the first case of animal-to-human infection transmission that causes a moderate decreased sensitivity to neutralizing antibodies. Thus, more investigations are necessary. It remains important to understand the risk that people with COVID-19 pose to their pets, as well as wild or farm animals so effective recommendations and risk management measures against COVID-19 can be made. A One Health unit that facilitates collaboration between public health and veterinary services is recommended.

Effects of orexins on 17ß-estradiol synthesis and P450 aromatase modulation in the testis of alpaca (Vicugna pacos).

The steroidogenic enzyme P450 aromatase (ARO) has a key role in the conversion of testosterone (T) into estrogens (E), expressed as 17ß-estradiol. The presence and localization of this key enzyme have not been described before in the South American camelid alpaca (Vicugna pacos). In our previous studies of the expression and biological effects of orexin A (OxA) and OxB on the alpaca testis demonstrated that OxA, via its specific receptor 1 (OX1R), stimulated T synthesis. In order to extend these findings, we presently explored the presence and localization of ARO in the alpaca male gonad, and the possible correlation between ARO and the orexinergic complex. Western blotting and immunohistochemistry demonstrated the presence of ARO in tissue homogenates and its localization in the tubular and interstitial compartments of the alpaca testis, respectively. The addition of OxA to fresh testicular slices decreased the 17ß-estradiol E levels. This effect was annulled by the sequential addition of the selective OX1R antagonist, SB-408124. OxB incubation did not have any effect on the biosynthesis of E. Furthermore, the OxA-mediated down-regulation of E secretion could be ascribed to ARO inhibition by exogenous OxA, as indicated by measurement of ARO activity in tissue slices incubated with OxA. Overall, our findings suggest that locally secreted OxA interacting with OX1R could indirectly inhibit ARO activity, disabling the conversion of T to E, and consequently lowering E biosynthesis and increasing the production of T in mammalian testis.

Localization of orexin B and orexin-2 receptor in the rat epididymis.

The peptides orexin A (OXA) and orexin B (OXB) derived from the proteolytic cleavage of a common precursor molecule, prepro-orexin, were originally described in the rat hypothalamus. Successively, they have been found in many other brain regions as well as in peripheral organs of mammals and other less evolved animals. The widespread localization of orexins accounts for the multiple activities that they exert in the body, including the regulation of energy homeostasis, feeding, metabolism, sleep and arousal, stress, addiction, and cardiovascular and endocrine functions. Both OXA and OXB peptides bind to two G-coupled receptors, orexin-1 (OX1R) and orexin-2 (OX2R) receptor, though with different binding affinity. Altered expression/activity of orexins and their receptors has been associated with a large number of human diseases. Though at present evidence highlighted a role for orexins and cognate receptors in mammalian reproduction, their central and/or local effects on gonadal functions remain poorly known. Here, we investigated the localization of OXB and OX2R in the rat epididymis. Immunohistochemical staining of sections from caput, corpus and cauda segments of the organ showed intense signals for both OXB and OX2R in the principal cells of the lining epithelium, while no staining was detected in the other cell types. Negative results were obtained from immunohistochemical analysis of hypothalamic and testicular tissues from OX2R knock-out mice (OX2R-/-) and OX1R/OX2R double knock-out (OX1R-/-; OX2R-/-) mice, thus demonstrating the specificity of the rabbit polyclonal anti-OX2R antibody used in our study. On contrary, the same antibody clearly showed the presence of OX2R in sections from hypothalamus and testis of normal mice and rats which are well known to express the receptor. Thus, our results provide the first definite evidence for the immunohistochemical localization of OXB and OX2R in the principal cells of rat epididymis.

2,3,7,8-Tetrachlorodibenzo-p-dioxin influences bovine herpesvirus 1 replication through upregulation of SIRT3 and cytoskeletal reorganization.

Infection of kidney cells (MDBK) with Bovine Herpesvirus 1 (BoHV-1) is affected by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which accelerates BoHV-1-induced apoptosis and increases virus replication. Herein, to elucidate the mechanism through TCDD modifies BoHV-1 infection, we analyzed the modulation of a members of Sirtuin proteins family in MDBK cells. We found that mitochondrial SIRT3 was upregulated during infection. This change was accompanied by cytoskeletal rearrangements and cell extensions. All these trends were drastically modified by TCDD. We hypothesize that, taken together, these results might further clarify the processes responsible for the action of TCDD on the BoHV-1 replication, resulting in enhanced virus production.

Region-specific distribution of the P2Y4 receptor in enteric glial cells and interstitial cells of Cajal within the guinea-pig gastrointestinal tract.

Although there is pharmacological evidence to assume that the P2Y4 receptor is a regulator of epithelial ion transport, no detailed data about its distribution within the gut are available. Therefore, this study, using whole mounts and cryosections, aimed to reveal the expression pattern of P2Y4 along the entire guinea-pig gastrointestinal tract. P2Y4 immunoreactivity was absent from enteric neurons but present in enteric glial cells of the stomach, small and large intestine. In the esophagus, P2Y4 appeared to be exclusively located within striated muscle cells. P2Y4 showed also a region dependency regarding its presence in different subpopulations of interstitial cells of Cajal: in myenteric interstitial cells of Cajal in the stomach and ileum; in some intramuscular interstitial cells in the stomach and cecum; in some deep muscular plexus interstitial cells in the ileum; and in some submucosal surface interstitial cells in the colon. These results and the knowledge that P2Y4 activation causes intracellular Ca2+ recruitment led us to suggest that P2Y4 in enteric glia plays a modulatory role in intercellular Ca2+ waves, while P2Y4 in interstitial cells of Cajal modulates intracellular Ca2+ oscillations.

The endocannabinoid system and the molecular basis of paralytic ileus in mice.

The endocannabinoid system (i.e., the cannabinoid receptors and their endogenous ligands) plays an important role in the physiological control of intestinal motility. However, its participation in intestinal pathological states is still poorly understood. In the present study, we investigated the possible role of the endocannabinoid system in the pathogenesis of paralytic ileus, a pathological state consisting of decreased intestinal motility following peritonitis, surgery, or other noxious situations. Ileus was induced by i.p. administration of acetic acid, and gastrointestinal propulsion was assessed by the charcoal method. Endocannabinoid levels were measured by isotope-dilution gas chromatography-mass spectrometry, whereas cannabinoid CB1 receptors were identified by immunohistochemistry. Acetic acid administration inhibited gastrointestinal transit (ileus), and this effect was accompanied by increased levels of the endocannabinoid anandamide compared with control mice and by overexpression of CB1 receptors in myenteric nerves. Furthermore, acetic acid-induced ileus was alleviated by the CB1 receptor antagonist SR141716A and worsened by VDM11, a selective inhibitor of anandamide cellular uptake (and hence inactivation). From these findings, it can be concluded that the intestinal hypomotility typical of paralytic ileus is due, at least in part, to the enhancement of anandamide levels and CB1 expression during this condition, and that selective, nonpsychotropic CB1 receptor antagonists could represent new drugs to treat this disorder.

Glial fibrillary acidic protein-immunoreactive enteroglial cells in the jejunum of cattle.

Enteroglial cells (EGCs) play critical roles in human health and disease, however, EGC-dependent neuropathies also affect commercially important animal species. Due to the lack of data on the distribution and phenotypic characterization of the EGCs throughout the bovine gastrointestinal tract, in this study the topographic localization of EGCs in the jejunum of healthy cattle was investigated by immunofluorescence using the glial specific marker glial fibrillary acidic protein (GFAP) and the panneuronal marker PGP 9.5. This analysis was conducted on both cryosections and whole mount preparations including the myenteric and the submucous plexuses of the bovine jejunum. The results obtained showed the presence of a large subpopulation of GFAP-expressing EGCs in the main plexuses and within the muscle layers, whereas only few GFAP-positive glial processes were found within the deeper layer of the mucosa, and they never reached the mucosal epithelium. Three different EGC subtypes, namely I, III and IV types were recognized in the examined tract of the bovine intestine. Overall, our results provide the basis for future investigations aimed at elucidating the functional role of the GFAP-containing EGCs which is crucial for a better understanding of the physio-pathology of the bovine intestine.