Rocco Latorre

Taste signalling molecules are found in the gastrointestinal (GI) tract suggesting that they participate to chemosensing. We tested whether fasting and refeeding affect the expression of the taste signalling molecule, α-transducin (Gαtran ), throughout the pig GI tract and the peptide content of Gαtran cells. The highest density of Gαtran -immunoreactive (IR) cells was in the pylorus, followed by the cardiac mucosa, duodenum, rectum, descending colon, jejunum, caecum, ascending colon and ileum. Most Gαtran -IR cells contained chromogranin A. In the stomach, many Gαtran -IR cells contained ghrelin, whereas in the upper small intestine many were gastrin/cholecystokinin-IR and a few somatostatin-IR. Gαtran -IR and Gαgust -IR colocalized in some cells. Fasting (24 h) resulted in a significant decrease in Gαtran -IR cells in the cardiac mucosa (29.3 ± 0.8 versus 64.8 ± 1.3, P < 0.05), pylorus (98.8 ± 1.7 versus 190.8 ± 1.9, P < 0.0 l), caecum (8 ± 0.01 versus 15.5 ± 0.5, P < 0.01), descending colon (17.8 ± 0.3 versus 23 ± 0.6, P < 0.05) and rectum (15.3 ± 0.3 versus 27.5 ± 0.7, P < 0.05). Refeeding restored the control level of Gαtran -IR cells in the cardiac mucosa. In contrast, in the duodenum and jejunum, Gαtran -IR cells were significantly reduced after refeeding, whereas Gαtran -IR cells density in the ileum was not changed by fasting/refeeding. These findings provide further support to the concept that taste receptors contribute to luminal chemosensing in the GI tract and suggest they are involved in modulation of food intake and GI function induced by feeding and fasting.

Most investigations related to the characterisation of the enteric nervous system (ENS) are pivoted on the intestine of small rodents, but few studies are available on the ENS of wild or 'unconventional' rodents. Anti-PGP 9.5 and anti-Hu antibodies were utilised to recognise the distribution pattern of neuronal cell bodies and fibres of the ileum of the Persian squirrel (Sciurus anomalus) ENS. The percentages of subclasses of enteric neurones in the total neuronal population were investigated by neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), calcitonin gene-related peptide (CGRP), substance P (SP), and calbindin (CALB). Myenteric plexus (MP) and submucosal plexus (SMP) neurones showing nNOS immunoreactivity (IR) were 41±4% and 11±6%, respectively, whereas cells expressing ChAT-IR were 56±9% and 74±16%, respectively. nNOS-IR was co-expressed by 21±2% and 9±4% of the MP and SMP cholinergic neurones, respectively, whereas the nNOS-IR MP and SMP neurones co-expressing ChAT-IR were 86±6% and 89±2%, respectively. CGRP-IR and SP-IR were expressed, respectively, by 13±5% and 6±3% of MP and 18±2% and 2±2% of SMP neurones. CALB-IR was expressed by 22±8% and 56±14% of MP and SMP neurones, respectively. MP and SMP cholinergic neurones co-expressed nNOS-IR (21±2% and 9±4%, respectively) and a very high percentage of nNOS-IR neurones showed ChAT-IR (86±6% and 89±2%, respectively). MP and SMP CALB-IR neurones co-expressed ChAT-IR (100% and 63±11%, respectively) and CGRP-IR (89±5% and 26±7%, respectively). Our data might contribute to the neuroanatomical knowledge of the gastrointestinal tract in exotic mammals and provide a comparison with the available data on other mammals.

Background and Aims: The enteric nervous system (ENS) is the major player controlling gastrointestinal (GI) functions. In addition, the ENS can be a target of a variety of pathological conditions, including Parkinson’s disease (PD). PD patients are known to suffer from different GI manifestations, the most common being chronic constipation (CC). CC in PD (PD/CC) remains poorly elucidated and the neurochemical/molecular mechanisms underlying its pathophysiology, compared to conventional CC, are still unknown. We analyzed colonic specimens in three groups of patients: PD/CC, CC and control subjects, focusing to the secretomotor neuron component and glial cells. Methods: In PD/CC and CC patients, symptoms were evaluated by the Rome III questionnaire a thorough GI functional assessment. Twenty-six PD patients (6F, 20M; age range: 64–85 years), 4 CC patients (4F, age range 36–71 years) and 18 asymptomatic controls (7F, 11M; age range: 44–77 years; screening colonoscopy) were enrolled. Ea...

To assess anti-neuronal antibodies (NA) prevalence and their correlation with neurological disorders and bowel habits in celiac disease (CD) patients. Neurological manifestations are estimated to occur in about 10% of celiac disease patients and NA to central nervous system (CNS) and enteric nervous system (ENS) are found in a significant proportion of them. Little is known about the clinical and immunological features in CD patients with neurological manifestations. NA to CNS and ENS were investigated in 106 CD patients and in 60 controls with autoimmune disorders by indirect immunofluorescence on rat / primate cerebellar cortex and intestinal (small and large bowel) sections. IgG NA to CNS (titer 1:50 - 1:400) were positive in 23 celiacs (21%), being more frequently detected in those with neurological disorders that in those without neurological dysfunction (49% vs. 8%, P< 0.0001). Of the 26 celiacs (24%) with IgG NA to ENS, 11 out of 12 with an antibody titer > 1:200 had se...

Since their discovery at the end of the 19th century, enteric glial cells (EGCs), the major cellular component of the enteric nervous system, have long been considered mere supportive cells for neurons. However, recent evidence has challenged this view and highlighted their central role in the regulation of gut homeostasis as well as their implication in digestive and extradigestive diseases. In this review, we summarize emerging concepts as to how EGCs regulate neuromediator expression, exert neuroprotective roles, and even act as neuronal as well as glial progenitors in the enteric nervous system. A particularly crucial property of EGCs is their ability to maintain the integrity of the intestinal epithelial barrier, a role that may have important clinical implications not only for digestive diseases, such as postoperative ileus and inflammatory bowel diseases, but also for extradigestive diseases, such as Parkinson disease or obesity. EGCs could also contribute directly to disease...

Objective: Chronic constipation (CC) is a well recognized gastrointestinal (GI) disturb in most Parkinson’s disease (PD) patients. Nonetheless, the clinical features and the attendant enteric neuropathological / neurochemical abnormalities of CC in PD patients (CC/PD) are still largely undefined. In CC/PD patients our goals were to: (i) characterize CC by assessing colonic transit time (TT) and anorectal manometry (AM); (ii) analyze possible neurochemical abnormalities of colonic submucosal neuron. Methods: CC and related symptoms were assessed using the Rome III criteria, while PD was established by a Unified Parkinson’s Disease Rating Scale (part III). CC was characterized in 25 PD patients (7F, 18M; age range: 64–85 years) by TT, AM and colonoscopy; 14 control subjects (4F, 10M; age range: 33–77 years) undergoing screening colonoscopy were included. Using routine biopsies during colonoscopy, we obtained submucosal specimens with related neural network in 10 CC/PD patients and 10 ...

β(3) -Adrenoceptors participate in the regulation of vascular tone in physiological and pathological conditions. We aimed to assess the effect of pharmacological modulation of β(3) -adrenoceptors on portal pressure (PP) and systemic haemodynamics and their expression in the liver and mesenteric vessels of cirrhotic rats. PP, central venous pressure (CVP) and systemic haemodynamics were invasively assessed in control and CCl(4) -treated cirrhotic rats before and during infusion of the selective β(3) -adrenoceptor agonist, SR58611A. Tissue samples were also collected from liver, heart, portal vein and mesenteric artery for immunohistochemistry and molecular biology analysis. The effect of SR58611A on isolated portal vein was assessed. At baseline, cirrhotic rats showed portal hypertension, reduced CVP and hyperdynamic circulation. SR58611A induced a significant, dose-dependent decrease in PP in cirrhotic rats, but not in controls. Although both groups manifested a dose-dependent reduction in mean arterial pressure, this effect was associated with decreased cardiac index (CI) and unchanged indicized peripheral vascular resistance (PVRI) in cirrhotic rats and increased CI and decreased PVRI in control animals. Pretreatment with the selective β(3) -adrenoceptor antagonist SR59230 prevented all SR58611A-induced changes in cirrhotic rats. SR58611A concentration-dependently relaxed portal vein in cirrhotic rats to a significantly greater extent than in healthy rats; pretreatment with SR59230A completely prevented SR58611A-induced cirrhotic portal vein relaxation. Finally, β(3) -adrenoceptors were identified in the liver, heart and portal vein of cirrhotic and control animals; their expression was increased in cirrhotic rats. β(3) -Adrenoceptors are altered in portal hypertension of experimental cirrhosis and may represent a novel therapeutic target.