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Serotonin is crucial in gastrointestinal functions, including motility, sensitivity, secretion, and the inflammatory response. The serotonin transporter (SERT), responsible for serotonin reuptake and signaling termination, plays a prominent role in gastrointestinal physiology, representing a promising therapeutic target in digestive disorders. Serotonin transporter expression has been poorly investigated in veterinary medicine, under both healthy and pathological conditions, including canine chronic enteropathy, in which the serotonin metabolism seems to be altered. The aim of the present study was to determine the distribution of SERT immunoreactivity (SERT-IR) in the dog intestine and to compare the findings with those obtained in the rat and human intestines. Serotonin transporter-IR was observed in canine enterocytes, enteric neurons, lamina propria cells and the tunica muscularis. Data obtained in dogs were consistent with those obtained in rats and humans. Since the majority of the serotonin produced by the body is synthesized in the gastrointestinal tract, SERT-expressing cells may exert a role in the mechanism of serotonin reuptake.

In the original article, there was a mistake in the legend for Figure 3 as published. The legend of Figure 3 (g-l) is incorrect. The correct legend appears below. FIGURE 3 | Photomicrographs of cryosections of canine cervical (C8) dorsal root ganglion showing cannabinoid receptor 2- (CB2), glial fibrillary acidic protein- (GFAP), and CD31-immunoreactivity. (a–c) Stars indicate NeuroTrace labeled (a) dorsal root ganglion sensory neurons which were CB2 receptor negative (b), as well as the satellite glial cells (white arrows). (d–f) Stars indicate sensory neurons encircled by satellite glial cells (white arrows) which were GFAP-immunoreactive (e) and CB2 receptor negative. CB2 receptor immunoreactivity was expressed by Schwann cells and neuronal nuclei (open arrow). (g–i) The empty arrow indicates one neuronal axon that bifurcates (T-junction) in its central and peripheral portions (large white arrows). The small arrows indicate the nuclei of Schwann cells. (j–l) Open arrows indicate smooth muscle cells (vessel on the left) and pericyte-like cells (elongated and thin blood vessel on the right) showing CB2 receptor immunoreactivity (j).White arrows indicate endothelial cells showing CD31 immunoreactivity (k). Bar: a–f, j–l = 50μm; g–i = 100 μm. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.

Despite numerous studies carried out over the last 15 years in veterinary medicine, the pathogenesis of canine Inflammatory Bowel Disease (IBD) has still not been completely elucidated. In particular, unlike what has been demonstrated in human medicine, the influence of serotonin on clinical signs in canine IBD has not yet been clarified. The objective of this paper has been to seek a possible correlation between duodenal epithelial distribution of serotonin-producing cells (enterochromaffin cells) and disease-grading parameters (clinical, clinico-pathological, endoscopic and histopathological) in dogs with IBD. The medical records of dogs with a diagnosis of IBD were retrospectively reviewed and 21 client-owned dogs with a diagnosis of IBD were registered. Clinical score (by Canine Chronic Enteropathy Clinical Activity Index), laboratory examinations (albumin, total cholesterol, folate, cobalamin), endoscopic score and histopathological score, were compared by regression analysis with duodenal enterochromaffin cell percentage. The study results suggested a relationship between a decrease in folate absorption and an increase in duodenal enterochromaffin cell percentage (regression equation y=16.89-6.14x; coefficient of determination r2= 0.7; significant level: P=0.007). However no significant relationship was evidenced between duodenal enterochromaffin cell percentage and the other analyzed variables.

Sebbene il sistema nervoso enterico (ENS) svolga un ruolo cruciale nella scrapie ovina, non vi sono dati sulle popolazioni cellulari coinvolte nell’infezione, né sugli eventuali danni da esse subiti. Il presente studio è stato condotto sui plessi mienterici e sottomucosi dell’ileo di 32 pecore di razza Sarda, recanti diversi genotipi (ARQ/ARQ, ARQ/AHQ, ARQ/ARR, ARR/ARR) con riferimento al gene codificante per la PrPC. I suddetti animali, infettati per os all’età di 8 mesi con un ceppo di scrapie caratterizzato nel topo, sono stati sacrificati mediante eutanasia a determinati intervalli di tempo dall’infezione (p.i.). E’ stata quindi valutata, tramite immunoistochimica ed immunofluorescenza indiretta su sezioni tessutali e su preparati “wholemount”, l’immunoreattività (IR) nei confronti della PrPSc, del “marker” pan-neuronale Hu C/D, dell’ossido-nitrico sintetasi (nNOS), della calbindina (CALB), della proteina fibrillare acida gliale (GFAP) e della sinaptofisina. In 8 pecore con genotipo ARQ/ARQ, clinicamente sane e sacrificate a 12-24 mesi p.i., nonché in 4 ovini clinicamente affetti (1 con genotipo ARQ/ARQ, 3 con genotipo ARQ/AHQ), questi ultimi sacrificati rispettivamente a 24, 35, 36,3 e 39,5 mesi p.i., le indagini immunoistochimiche hanno rivelato la presenza di PrPSc sia nell’encefalo (obex), sia nell’ENS, specialmente nei plessi mienterici. In tali distretti il deposito della PrPSc era compatibile con un interessamento delle cellule enterogliali (EGCs), mentre in 6 animali con genotipo ARQ/ARQ era evidente un drastico calo numerico (P < 0,05) dei neuroni CALB-IR rispetto ai soggetti di controllo ed a quelli con differente genotipo infettati per os. Inoltre, i neuroni CALB-IR mostravano una pressoché esclusiva IR nucleare. I nostri dati supportano un coinvolgimento delle EGCs e dei neuroni CALB-IR dei plessi nervosi ileali nella scrapie ovina.

The Persian Squirrel (Sciurus anomalus) is the only member of the Sciuridae family found in the Middle East. It is herbivorous, feeding mostly on pine acorns and other seeds and fruits. It is a wild animal nesting in forest trees, although it is frequently found close to city gardens and parks. As Persian squirrels are also found in homes as "companion animals", veterinarian assistance may be sometimes required; this is a good reason to gain more specific knowledge of the anatomical features of this animal. Due to the scantiness of relevant literature, we carried out this study with the aim to provide further information on the topography and gross anatomy of its abdominal gastrointestinal tract (GIT). Seven animals of this species were utilized to measure the length, content weight and area surface of the relative segments of the abdominal GIT. The stomach is unilocular, lined with glandular epithelium; the small intestine is divided into duodenum, jejunum and ileum. The cecum is situated on the right side of the abdominal cavity and lacks the vermiform appendix observed in some rodents. The ascending colon is extensive, consisting of two loops and two straight parts forming a unique topographic arrangement, closely resembling the ascending colon of the horse. The transverse colon connects the ascending and the descending colon located on the left side of the abdominal cavity, and shows a distinct sigmoid flexure before entering the pelvic cavity. Overall, the in situ examination and the relative measurements of the various parts of the abdominal GIT suggest that the ascending colon is the main fermentation chamber in the Persian Squirrel. La ardilla es el único miembro de la familia de los Sciuridae que se encuentra en el Medio Oriente. Es un herbívoro, come semillas, principalmente de pino, y fruta. Vive mayormente en el bosque en estado salvaje, aunque a veces se puede encontrar en las ciudades, en parques y jardines. Las ardillas persianas tambien se tienen en casas como mascotas y algunas veces es necesaria la atención del veterinario. Esta es una buena razón para conocer más profundamente sus características anatómicas. Teniendo en cuenta la escasa bibliografía existente a cerca de este animal, el objetivo de este estudio fue aportar nueva información sobre la anatomía topográfica y mascroscópica del tracto abdominal gastrointestinal (GIT) de la ardilla. Siete animales de esta especie han sido utilizados para medir el largo, el peso y el área de la superficie de los segmentos del GIT. El estómago es unilocular, alineado con epitelio glandular; el pequeño intestino está dividido en duodeno, jejuno e ileo. El ciego está localizado en la parte derecha de la cavidad abdominal y le falta el apéndice vermiforme que poseen los roedores. El colon ascendente es extenso, constituido de dos partes curvas y dos rectilíneas que forman una única dispoción topográfica cerrada como el colon ascendente en el caballo. El colon trasverso, que conecta el ascendente y el descendente, está localizado en el lado izquierdo de la cavidad abdominal y muestra una clara flexión sigmoide antes de entrar en la cavidad pélvica. En resumen, el examen in situ y las relativas medidas de las varias partes del GIT sugieren que el colon ascendente es la principal "cámara" de fermentación en la ardilla persiana.

The double fluorescent retrograde tracing technique was used to identify, within the coeruleus complex (Co complex) of the duck, the nerve cells projecting to the cerebellar cortex and to the spinal cord. This technique was also used to investigate the possibility that the cerebellar and spinal projections of the Co complex are collaterals of the same axons. In the same animal, nuclear Diamidino yellow dihydrochloride (DY) fluorescent tracer was placed into the cerebellar cortex of folia V-VII, and cytoplasmic fluorescent Fast blue (FB) dye was injected into C3-C4 spinal cord segments. FB labeled multipolar somata and DY fluorescent nuclei were intermingled within the dorsal caudal region of the locus coeruleus (LCo) and within the dorsal division of the nucleus subcoeruleus (dSCo). Moreover, in the LCo, a low proportion of double-labeled neurons (about 3-4% of labelings) was evidenced among single-labeled neurons. In the ventral division of the nucleus subcoeruleus (vSCo), occasional DY labeled nuclei were found, whereas FB-labeled cells were frequently present. The present findings reveal the location of the coeruleocerebellar and coeruleospinal projecting neurons within the Co complex of the duck. They are intermingled in the caudal portion of the LCo and along the rostrocaudal extent of the subjacent dSco. The LCo and the dSCo are the major source of the projections to the folia V- VII, whereas the vSCo contributes very slightly to the innervation of the cerebellar injected areas. Moreover, the doublelabeling study demonstrates that in the duck a low percentage of neurons within the ventrolateral portion of the caudal region of the LCo projects both to the cerebellar cortex of folia V-VII and to C3-C4 spinal cord segments via collaterals. Therefore, these neurons simultaneously influence the cerebellar cortex and spinal cord. The possibility that the projections studied are noradrenergic and that they play a role in feeding is discussed.