Cristiano Bombardi

Regulation of α-Transducin and α-Gustducin Expression by a High Protein Diet in the Pig Gastrointestinal Tract

Background The expression of taste receptors (TASRs) and their signalling molecules in the gastrointestinal (GI) epithelial cells, including enteroendocrine cells (EECs), suggests they participate in chemosensing mechanisms influencing GI physiology via the release of endocrine messengers. TASRs mediate gustatory signalling by interacting with different transducers, including α-gustducin (Gαgust) and α-transducin (Gαtran) G protein subunits. This study tested whether Gαtran and Gαgust immunoreactive (-IR) cells are affected by a short-term (3 days) and long-term (30 days) high protein (Hp) diet in the pig GI tract. Result In the stomach, Gαgust and Gαtran-IR cells contained serotonin (5-HT) and ghrelin (GHR), while in the small and large intestine, Gαgust and Gαtran-IR colocalized with 5-HT-, cholecystokinin (CCK)- and peptide YY (PYY)-IR. There was a significant increase in the density of Gαtran-IR cells in the pyloric mucosa in both short- and long-term Hp diet groups (Hp3 and Hp30) vs. the control group (Ctr) (P<0.05), while the increase of Gαgust-IR cells in the pyloric mucosa was significant in Hp30 group vs. Ctr and vs. Hp3 (P<0.05); these cells included Gαtran / 5HT-IR and Gαtran / GHR-IR cells (P<0.05 and P<0.001 vs. Ctr, respectively) as well as Gαgust /5-HT-IR or Gαgust / GHR-IR cells (P<0.05 and P<0.01 vs. Ctr, respectively). In the small intestine, we recorded a significant increase in Gαtran-IR cells in the duodenal crypts and a significant increase of Gαgust-IR cells in the jejunal crypts in Hp3 group compared to HP30 (P<0.05). With regard to the number of Gαtran-Gαgust IR cells colocalized with CCK or 5-HT, there was only a significant increase of Gαtran / CCK-IR cells in Hp3 group compared to Ctr (P = 0.01). Conclusion This study showed an upregulation of selected subpopulations of Gαgust / Gαtran-IR cells in distinct regions of the pig GI tract by short- and long-term Hp diet lending support to TASR-mediated effects in metabolic homeostasis and satiety mechanisms.

Localization of the 5‐hydroxytryptamine 4 receptor in equine enteric neurons and extrinsic sensory fibers

Serotonin plays a pivotal role in regulating gut motility, visceral sensitivity, and fluid secretion via specific receptors. Among these receptors, 5‐HT4 exerts a prominent control on gut motor function. Although the prokinetic effect exerted by 5‐HT4 agonists is well known, the cellular sites of 5‐HT4 expression remain poorly understood in large mammals, e.g., horses. In this study, we evaluated the distribution of 5‐HT4 in the horse intestine and in foals with enteric aganglionosis, reminiscent of human Hirschsprungs disease.

The laminar organization of the motor cortex in monodactylous mammals: a comparative assessment based on horse, chimpanzee, and macaque

The architecture of the neocortex classically consists of six layers, based on cytological criteria and on the layout of intra/interlaminar connections. Yet, the comparison of cortical cytoarchitectonic features across different species proves overwhelmingly difficult, due to the lack of a reliable model to analyze the connection patterns of neuronal ensembles forming the different layers. We first defined a set of suitable morphometric cell features, obtained in digitized Nissl-stained sections of the motor cortex of the horse, chimpanzee, and crab-eating macaque. We then modeled them using a quite general non-parametric data representation model, showing that the assessment of neuronal cell complexity (i.e., how a given cell differs from its neighbors) can be performed using a suitable measure of statistical dispersion such as the mean absolute deviation—mean absolute deviation (MAD). Along with the non-parametric combination and permutation methodology, application of MAD allowed not only to estimate, but also to compare and rank the motor cortical complexity across different species. As to the instances presented in this paper, we show that the pyramidal layers of the motor cortex of the horse are far more irregular than those of primates. This feature could be related to the different organizations of the motor system in monodactylous mammals.

Mice overexpressing lamin B1 in oligodendrocytes recapitulate the age-dependent motor signs, but not the early autonomic cardiovascular dysfunction of autosomal-dominant leukodystrophy (ADLD)

ABSTRACT Autosomal dominant leukodystrophy (ADLD) is a rare adult‐onset demyelinating disease caused by overexpression of lamin B1, a nuclear lamina filament. Early autonomic dysfunction involving the cardiovascular system before progressive somatic motor dysfunction is a striking feature of most cases of ADLD. In the Plp‐FLAG‐LMNB1 transgenic mouse model, lamin B1 overexpression in oligodendrocytes elicits somatic motor dysfunction and neuropathology akin to ADLD. Here, we investigate whether Plp‐FLAG‐LMNB1 mice also develop autonomic cardiovascular dysfunction before or after somatic motor dysfunction. We find that Plp‐FLAG‐LMNB1 mice have preserved cardiovascular responses to changes in wake‐sleep state and ambient temperature and normal indexes of autonomic modulation at 37–42 weeks of age despite a progressive somatic motor dysfunction, which includes impairments of walking ability (the ability to walk on a narrow path was impaired in 80% of mice at 34–38 weeks of age) and subtle breathing derangements. Only late in the development of the disease phenotype did Plp‐FLAG‐LMNB1 mice develop a structural deficit of sympathetic noradrenergic fibers, with a 38% decrease in fiber profiles in the kidneys at 44–47 weeks of age. We demonstrate that while the Plp‐FLAG‐LMNB1 mouse model recapitulates the age‐dependent motor dysfunction of ADLD, it does not show signs of early autonomic cardiovascular dysfunction, raising the possibility that oligodendrocyte dysfunction may not be sufficient to cause the full spectrum of clinical features present in ADLD. HighlightsLamin B1 overexpression causes adult‐onset autosomal dominant leukodystrophy (ADLD).Age‐dependent motor dysfunction and early autonomic cardiovascular dysfunction are cardinal features of ADLD.Mice overexpressing lamin B1 in oligodendrocytes show age‐dependent motor dysfunction and a late loss of sympathetic fibers.However, these mice do not recapitulate the early autonomic cardiovascular dysfunction of ADLD.Lamin B1 overexpression in neurons or astrocytes may be key for the early development of autonomic cardiovascular dysfunction of ADLD.

Anatomical study of the musculus deltoideus and musculus flexor carpi ulnaris in 3 species of wild birds.

Given the limited information regarding the anatomy of the thoracic limb in European avian species, we decided to investigate the related muscles in the grey heron (Ardea cinerea), in the eurasian buzzard (Buteo buteo), and in the common kestrel (Falco tinnunculus). Therefore we performed a stratigraphic dissection of the wing in 3 subjects. The pars major and minor of the musculus deltoideus, despite being roughly in line with those reported by other authors in other species, displayed unique features. Concerning the pars propatagialis of the musculus deltoideus, from what was observed in the grey heron, we believe this structure can contribute to maintain the propatagial tension. In this way vibrations of this structure, which could cause diminished lift, are avoided. Moreover the peculiarity evidenced in the distal insertion of the common kestrel could influence the control of the pronation-supination of the wing during hovering. With respect to the musculus flexor carpi ulnaris, we believe the presence of a sesamoid-like structure at the base tendon, found in the grey heron and in the eurasian buzzard, may help complete the articular surfaces of the elbow. This study shows interesting data on species not previously examined and provides a possible functional correlation between the peculiarity observed and the kind of flight of each species.

Locus coeruleus complex of the family Delphinidae

The locus coeruleus (LC) is the largest catecholaminergic nucleus and extensively projects to widespread areas of the brain and spinal cord. The LC is the largest source of noradrenaline in the brain. To date, the only examined Delphinidae species for the LC has been a bottlenose dolphin (Tursiops truncatus). In our experimental series including different Delphinidae species, the LC was composed of five subdivisions: A6d, A6v, A7, A5, and A4. The examined animals had the A4 subdivision, which had not been previously described in the only Delphinidae in which this nucleus was investigated. Moreover, the neurons had a large amount of neuromelanin in the interior of their perikarya, making this nucleus highly similar to that of humans and non-human primates. This report also presents the first description of neuromelanin in the cetaceans’ LC complex, as well as in the cetaceans’ brain.

Developmental changes of GABA immunoreactivity in cortico-thalamic networks of an absence seizure model

ABSTRACT Absence seizures (ASs) are associated with abnormalities in gamma‐aminobutyric acid (GABA) neurotransmission in the thalamus and the cortex. In the present study, we used light microscopy GABA immunocytochemistry to quantify the GABA‐immunoreactive (GABA‐IR) neurons and neuropil in the thalamic ventral basal (VB) nucleus, the nucleus reticularis thalami (NRT), the dorsal lateral geniculate (dLGN), the primary motor cortex (M1) and perioral region of the somatosensory cortex (S1po) of genetic absence epilepsy rats from Strasbourg (GAERS). We used both the relative non‐epileptic control (NEC) and normal Wistar rats as control strains, and investigated GABA immunostaining at postnatal day 15 (P15), P25, and P90. The main findings were i) an increase in GABA‐IR neuropil in the VB at P25 and P90 in GAERS but not in NEC and Wistar rats; ii) an increase in NRT GABA‐IR neurons in GAERS and NEC, but not Wistar, rats at both P25 and P90; and iii) an increase in GABA‐IR neuron density in S1po of GAERS at P25 and P90 and in Wistar at P90. These results indicate that the increased GABAergic innervation in the VB at P25 most likely contributes to the enhanced tonic inhibition observed in GAERS prior to AS onset, whereas the lack of any anatomo‐morphological GABAergic differences in GAERS S1po suggests that functional more than structural abnormalities underlie the origin of cortical paroxysms in S1po of this AS model. This article is part of the “Special Issue Dedicated to Norman G. Bowery”. HIGHLIGHTSGABA‐IR profiles increase in P25 to P90 VB neuropil in GAERS but not in NEC and Wistar rats.NRT GABA‐IR neurons increase in P25 and P90 GAERS and NEC, but not in Wistar rats.GABA‐IR neuron density increases in S1po of GAERS at P25 and P90 and in Wistar at P90.

Preferential modulation of the lateral habenula activity by serotonin-2A rather than -2C receptors: Electrophysiological and neuroanatomical evidence

Serotonergic (5‐HT) modulation of the lateral habenula (LHb) activity is central in normal and pathologic conditions such as mood disorders. Among the multiple 5‐HT receptors (5‐HTRs) involved, the 5‐HT2CR seems to play a pivotal role. Yet, the role of 5‐HT2ARs in the control of the LHb neuronal activity is completely unknown.

Proteinase-activated receptor 2 distribution and expression in equine small intestine tracts following herniation through the epiploic foramen

Proteinase-activated receptor 2 (PAR2) is a G-protein-coupled receptor for trypsin and mast cell tryptase; it is highly expressed at the intestinal level with multiple functions, such as epithelial permeability and intestinal motility. The aim of the study was to evaluate the distribution and expression of proteinase-activated receptor 2 in the small intestine during herniation through epiploic foramen. In this prospective clinical study, eight horses admitted for colic and which underwent exploratory laparotomy were considered. During surgery, the jejunum or the ileum was sampled by enterectomy. Morphological examination (histology, PAR2 immunohistochemistry) and molecular biology analysis (western blot and quantitative polymerase chain reaction) were carried out on the resected intestinal samples. The Marginal Injured Tracts (MITs) and Central Injury Tracts (CITs) were defined as the oral and caudal marginal segments of the resected bowel tract and as the geometric centre of the intestinal ischaemic lesion length, respectively. The PAR2 immunoreactivity was particularly evident in the epithelial cells, with higher immunoreactivity in the MIT rather than in the CIT. Moreover, a different immune localisation was observed in the MITs at the cell membrane level and in the CITs in the cytoplasm. No statistical difference was observed in PAR2 mRNA and protein (44kDa) expression between the MIT and the CIT. The PAR2 protein content in the intestinal tracts which were removed from horses with herniation was lower when compared with the control animals. This study provided data concerning the PAR2 presence and distribution in horses with intestinal herniation through the epiploic foramen.

Distribution of Calretinin Immunoreactivity in the Lateral Nucleus of the Bottlenose Dolphin (Tursiops truncatus) Amygdala

The amgdaloid complex consists of different nuclei, each with unique cytoarchitectonic, chemoarchitectonic and connectional characteristics. Most of the inputs coming from cortical and subcortical areas enter the amygdala via the lateral nucleus, which makes it the main receiving structure of the complex. The activity of its neurons is coordinated and modulated by different inhibitory, GABAergic‐interneurons, which can be classified for their expression of various calcium‐binding proteins, as well as by morphological characteristics. This research based on the analysis of the amygdala of three bottlenose dolphins, provides the first description of the topography, cytoarchitecture and distribution of calretinin immunoreactivity of the lateral nucleus. Our observations on the bottlenose dolphin confirmed the general topography of the mammalian amygdala and of the lateral nucleus. Notably, we identified six subdivision of the nucleus, more than those reported until now in the rat, monkey and human lateral nucleus. This could reveal an outstanding capability of integration and elaboration of external stimuli. In addition, we observed a strong presence of CR‐immunoreactive (‐ir) neurons and fibres. CR‐ir neurons were mainly non‐pyramidal inhibitory neurons; in particular, 80% of IR‐cells were represented by large and small polygonal neurons. In the lateral nucleus of the human amygdala, CR‐ir neurons form inhibitory synapses on calbindin‐D28k‐IR inhibitory interneurons. Since calbindin‐D28k‐ir interneurons make inhibitory synapses on the pyramidal cells, the final goal of the CR‐ir interneurons could be the synchronization of cells activity, thus playing an important role in the control of information flow in the lateral amygdalar nucleus. Anat Rec, 2017.