Vasoactive Intestinal Polypeptide Immunoreactivity Research Articles

Distribution of vasoactive intestinal peptide (VIP) immunoreactivity in the rat pallial and subpallial amygdala and colocalization with γ-aminobutyric acid (GABA).

The amygdaloid complex, also known as the amygdala, is a heterogeneous group of distinct nuclear and cortical pallial and subpallial structures. The amygdala plays an important role in several complex functions including emotional behavior and learning. The expression of calcium-binding proteins and peptides in GABAergic neurons located in the pallial and subpallial amygdala is not uniform and is sometimes restricted to specific groups of cells. Vasoactive intestinal polypeptide (VIP) is present in specific subpopulations of GABAergic cells in the amygdala. VIP immunoreactivity has been observed in somatodendritic and axonal profiles of the rat basolateral and central amygdala. However, a comprehensive analysis of the distribution of VIP immunoreactivity in the various pallial and subpallial structures is currently lacking. The present study used immunohistochemical and morphometric techniques to analyze the distribution and the neuronal localization of VIP immunoreactivity in the rat pallial and subpallial amygdala. In the pallial amygdala, VIP-IR neurons are local inhibitory interneurons that presumably directly and indirectly regulate the activity of excitatory pyramidal neurons. In the subpallial amygdala, VIP immunoreactivity is expressed in several inhibitory cell types, presumably acting as projection or local interneurons. The distribution of VIP immunoreactivity is non-homogeneous throughout the different areas of the amygdaloid complex, suggesting a distinct influence of this neuropeptide on local neuronal circuits and, consequently, on the cognitive, emotional, behavioral and endocrine activities mediated by the amygdala.

De novo aging-related NADPH diaphorase positive megaloneurites in the sacral spinal cord of aged dogs

We investigated aging-related changes in nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in the spinal cord of aged dogs. At all levels of the spinal cord examined, NADPH-d activities were observed in neurons and fibers in the superficial dorsal horn (DH), dorsal gray commissure (DGC) and around the central canal (CC). A significant number of NADPH-d positive macro-diameter fibers, termed megaloneurites, were discovered in the sacral spinal cord (S1–S3) segments of aged dogs. The distribution of megaloneurites was characterized from the dorsal root entry zone (DREZ) into the superficial dorsal horn, along the lateral collateral pathway (LCP) to the region of sacral parasympathetic nucleus (SPN), DGC and around the CC, but not in the cervical, thoracic and lumbar segments. Double staining of NADPH-d histochemistry and immunofluorescence showed that NADPH-d positive megaloneurites co-localized with vasoactive intestinal peptide (VIP) immunoreactivity. We believed that megaloneurites may in part represent visceral afferent projections to the SPN and/or DGC. The NADPH-d megaloneurites in the aged sacral spinal cord indicated some anomalous changes in the neurites, which might account for a disturbance in the aging pathway of the autonomic and sensory nerve in the pelvic visceral organs.

Vasoactive Intestinal Polypeptide Plays a Key Role in the Microbial-Neuroimmune Control of Intestinal Motility

Background and AimsAlthough chronic diarrhea and constipation are common, the treatment is symptomatic as their pathophysiology is poorly understood. Accumulating evidence suggests that the microbiota modulates gut function but the underlying mechanisms are unknown. We therefore investigated the pathways by which microbiota modulates gastrointestinal motility in different sections of the alimentary tract. MethodsGastric emptying, intestinal transit, muscle contractility, acetylcholine release, gene expression and vasoactive intestinal polypeptide (VIP) immunoreactivity were assessed in wild-type and Myd88-/-Trif-/- mice in germ-free, gnotobiotic and SPF conditions. Effects of transient colonization and antimicrobials, as well as immune cell blockade were investigated. VIP levels were assessed in human full thickness biopsies by Western blot. ResultsGerm-free mice had similar gastric emptying but slower intestinal transit compared with SPF mice, or mice monocolonized with Lactobacillus rhamnosus or Escherichia coli, the latter having stronger effects. While muscle contractility was unaffected, its neural control was modulated by microbiota by upregulating jejunal VIP, which co-localized with and controlled cholinergic nerve function. This process was responsive to changes in the microbial composition and load, and mediated through TLR signaling, with enteric glia cells playing a key role. Jejunal VIP was lower in patients with chronic intestinal pseudo-obstruction compared with control subjects. ConclusionMicrobial control of gastrointestinal motility is both region- and bacteria-specific, it reacts to environmental changes, and is mediated by innate immunity-neural system interactions. Small intestinal VIP, by regulating cholinergic nerves, plays a key role in this process, thus providing a new therapeutic target for patients with motility disorders.

Immunohistochemical Distribution and Neurochemical Characterization of Huntingtin-Associated Protein 1 Immunoreactive Neurons in the Adult Mouse Lingual Ganglia

Huntingtin-associated protein 1 (HAP1) is a determinant marker for the stigmoid body (STB), a neurocytoplasmic physiological inclusion. STB/HAP1 enriched areas in the brain/spinal cord are usually protected from neurodegenerative diseases, whereas the regions with tiny amounts or no STB/HAP1 are affected. In addition to the brain/spinal cord, HAP1 is highly expressed in the myenteric/submucosal plexuses of the enteric nervous system in the gastrointestinal tract. The tongue is attached to the pharynx by the hyoid bone as an extension of the gastrointestinal system. To date, the immunohistochemical distribution and neurochemical characterization of HAP1 have not been elucidated in the lingual ganglia. Using immunohistochemistry and light microscopy, our current study demonstrates the expression and immunohistochemical phenotype of HAP1 in the lingual ganglia of adult mice. We showed that HAP1 was profoundly distributed in the intralingual ganglion (ILG) and the ganglia near the root of the tongue (which we coined as "lingual root ganglion"; LRG). Neurons in ILG and LRG exhibited high coexpression of HAP1 with NOS or ChAT. Furthermore, most HAP1-immunoreactive neurons contained SP, CGRP, and VIP immunoreactivity in both ILG and LRG. The current results might serve as an essential base for future studies to elucidate the pathological/physiological functions of HAP1 in the lingual ganglia.

Immunohistochemical characterization of nerve elements in porcine intrinsic laryngeal ganglia.

The present study investigated the chemical coding of neurons and nerve fibres in local laryngeal ganglia in pigs (n=5) using double-labelling immunohistochemistry. Virtually all the neurons were cholinergic in nature (ChAT- or VAChT-positive). Only very solitary, small nerve cells (presumably representing interneurons) stained intensely for adrenergic marker, DβH. Many neurons also contained immunoreactivity for NOS (91%), VIP (62.7%), NPY (24.7%), galanin (10%), SP (1.3%) and CGRP (5.3%). No neurons expressing somatostatin or Leu-enkephalin were observed. Nearly all the neuronal somata were densely supplied with varicose cholinergic nerve terminals, which presumably represented preganglionic axons, and some of them were also closely apposed with CGRP- and/or SP-positive varicose nerve endings, which were putative collaterals of extrinsic primary sensory fibres. In conclusion, this study has revealed that intrinsic neurons in the porcine larynx, like in many other mammalian species studied, should be classified as parasympathetic cholinergic neurons expressing biologically active substances, predominantly NOS and VIP. Furthermore, they are likely to receive inputs from not only preganglionic neurons but also primary sensory nerve cells. Finally, it appears that the information on the occurrence of the local laryngeal ganglia should be regularly included in textbooks dealing with the cranial portion of the parasympathetic nervous system in mammals.

Sexual dimorphism in the bed nucleus of the stria terminalis, medial preoptic area and suprachiasmatic nucleus in male and female tree shrews.

Sex differences in behaviour partly arise from the sexual dimorphism of brain anatomy between males and females. However, the sexual dimorphism of the tree shrew brain is unclear. In the present study, we examined the detailed distribution of vasoactive intestinal polypeptide-immunoreactive (VIP-ir) neurons and fibres in the suprachiasmatic nucleus (SCN) and VIP-ir fibres in the bed nucleus of the stria terminalis (BST) of male and female tree shrews. The overall volume of the SCN in male tree shrews was comparable with that in females. However, males showed a significantly higher density of VIP-ir cells and fibres in the SCN than females. The shape of the VIP-stained area in coronal sections was arched, elongated or oval in the lateral division (STL) and the anterior part of the medial division (STMA) of the BST and oval or round in the posterior part of the medial division of the BST (STMP). The volume of the VIP-stained BST in male tree shrews was similar to that in females. The overall distribution of VIP-ir fibres was similar between the sexes throughout the BST except within the STMA, where darkly stained fibres were observed in males, whereas lightly stained fibres were observed in females. Furthermore, male tree shrews showed a significantly higher intensity of Nissl staining in the medial preoptic area (MPA) and the ventral part of the medial division of the BST than females. These findings are the first to reveal sexual dimorphism in the SCN, BST and MPA of the tree shrew brain, providing neuroanatomical evidence of sexual dimorphism in these regions related to their roles in sex differences in physiology and behaviour.

Sex Differences in Neural – Immune – Epithelial Anatomical Plasticity in the Mouse Small Intestine

Background Pathways of neural signaling leading to alterations in gut wall immune – epithelial function are not well understood, particularly in the context of sex. Specific neural factors regulating epithelial or immune cell localization and secretion are emerging. Vasoactive intestinal peptide (VIP), often a neuropeptide, can play a role in goblet cell production (1) and signals bi-directionally with enteric mast cells (2). Immune components like mast cells are key in gut wall defense against pathogens. Epithelial components of host defense include goblet cells secreting mucus to form a physical barrier, and Paneth cells secreting anti-microbial compounds. Neural fibers course intimately with goblet and Paneth cells and may signal with gut mucosal mast cells (2). The present study establishes the anatomic arrangement of immunoreactive VIP (VIP-IR) fibers in relation to mast and Paneth cells in the mouse ileum, and tests the hypothesis that sex is a key variable in neural – immune – epithelial signaling in the gut wall in healthy and perturbed tissue. Methods We used an organotypic gut slice model that maintains the cellular diversity of the gut wall ex vivo. Slices were treated with selected pharmacological reagents that block neuronal function (e.g., tetrodotoxin) or VIP receptors prior to challenge with lipopolysaccharide (LPS) to assess their influence on anatomic plasticity of VIP-IR fibers with Paneth cells and mast cells at 48h ex vivo. Results There were more mast cells in females than males whether drop fixed in vivo (214%) or after 48h of ex vivo culture (53%). The mast cells in tissue from females drop fixed in vivo were ~18% larger than in males, and similarly ~26% larger in slices of ileum maintained ex vivo for 48h (Fig 1A-D). Approximately 70% of mast cells had VIP-IR fibers within 1µm, regardless of sex. However, those mast cells within 1 µm of a fiber were 15% larger than those without a nearby fiber, regardless of sex (Fig 1E-H). A small percentage of mast cells were induced to show substantial VIP-IR ex vivo only in slices treated with a VIP receptor antagonist or tetrodotoxin. Surprisingly, this effect occurred more in female slices (~200% more) than in male (Fig 1I-L). Paneth cells were labelled with the lectin Ulex europaeusagglutinin-1 and >75% were within 1 µm of a VIP-IR neuronal fiber, independent of sex or treatment with LPS. By contrast, Paneth cells in slices from females showed 51% greater fluorescent intensity than males, a difference not found after LPS treatment (Fig 2). Conclusions The present study demonstrates a close anatomical relationship of mast and Paneth cells with VIP-IR neuronal fibers. We extend previous work demonstrating a functional influence of VIP over goblet cell production in mouse ileum. The current results suggest sex differences in neural-immune and neural-epithelial plasticity that could potentially impact function. Additional data is needed to test the hypothesis that VIP has a functional role in regulating mast and Paneth cell secretion of histamine and anti-microbials in healthy and pathogen challenged states. References (1) Schwerdtfeger LA and Tobet SA. Physiol Rep 8:e14363, 2020. (2) Buhner S et al., Front Physiol 8:971, 2017.

High-fat Diet Enhances Gastric Contractility, but Abolishes Nesfatin-1-induced Inhibition of Gastric Emptying.

Background/AimsGastrointestinal motility changes contribute to development and maintenance of obesity. Nesfatin-1 (NES-1) is involved in central appetite control. The aim is to elucidate effects of NES-1 and high-fat diet (HFD) on gastrointestinal motility and to explore myenteric neuron expressions of tyrosine hydroxylase (TH), vasoactive intestinal peptide (VIP), and neuronal nitric oxide synthase (nNOS) in HFD-induced oxidative injury.MethodsSprague-Dawley rats were fed with normal diet (ND) or HFD. Gastric emptying rate was measured following NES-1 (5 pmol/rat, intracerebroventricular) preceded by subcutaneous injections of glucagon-like peptide 1 (GLP-1), cholecystokinin 1 (CCK-1), and gastrin/CCK-2 receptor antagonists. In carbachol-contracted gastric and ileal strips, contractile changes were recorded by adding NES-1 (0.3 nmol/L), GLP-1, CCK-1, and gastrin/CCK-2 antagonists.ResultsNeither HFD nor NES-1 changed methylcellulose emptying, but NES-1 delayed saline emptying in cannulated ND-rats. Inhibitory effect of NES-1 on gastric emptying in ND-rats was reversed by all antagonists, and abolished in HFD-rats. In HFD-rats, carbachol-induced contractility was enhanced in gastric, but inhibited in ileal strips. HFD increased body weight, while serum triglycerides, alanine transaminase, aspartate aminotransferase, glucose, and levels of malondialdehyde, glutathione, myeloperoxidase activity, and luminol-chemiluminescence in hepatic, ileal, and adipose tissues were similar in ND- and HFD-rats, but only lucigenin-chemiluminescence was increased in HFD-rats. Vasoactive intestinal peptide (VIP) and TH immunoreactivities were depressed and nNOS immunoreactivity was increased in gastric tissues of HFD-rats, while VIP and TH were enhanced, but nNOS was reduced in their intestines.ConclusionsHFD caused mild systemic inflammation, disrupted enteric innervation, enhanced gastric contractility, inhibited ileal contractility, and eliminated inhibitory effect of NES-1 on gastric motility.

Gastric motor dysfunction coincides with the onset of obesity in rats fed with high-fat diet.

Exposure to a high-fat diet (HFD) has been reported to impair central autonomic and enteric neurocircuitries, however, the relevant mechanisms and their time course are inadequately clarified. This study aimed to investigate the effects of HFD consumption through the period of adolescence on gastric motor functions in adulthood. Male Sprague-Dawley rats consumed a regular diet or HFD (60% kcal by fat) from 4 to 12 weeks of age. Body weight and food intake were monitored weekly. In adult rats, gastric emptying (GE) was measured. Additionally, using in-vitro organ bath, contractile and relaxant responses of antral and fundic strips were assessed with bethanechol and sodium nitroprusside (SNP), respectively. The expressions of choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP) were detected by immunofluorescence, whereas, the number of myenteric neurons were evaluated by staining with cuprolinic blue and enteric neuronal marker PGP 9.5. In adulthood, the HFD did not alter food intake, while significantly increasing the body weight. In HFD-fed adult rats, increased visceral fat mass was accompanied by delayed GE. Moreover, bethanechol- and SNP-induced responses were attenuated in antral and fundic tissues. HFD remarkably decreased the number of myenteric neurons and NOS immunoreactivity both in fundus and antrum. HFD remarkably decreased ChAT expression, while increasing the immunoreactivity for VIP in antrum. In conclusion, consumption of HFD between early adolescence and adulthood results in obesity and impairment of gastric motor functions. Particularly, HFD-induced gastric dysmotility appears to be predominantly dependent on the modifications in the non-adrenergic non-cholinergic inhibitory neurotransmission.

Glucagon-like peptide-2 interferes with the neurally-induced relaxant responses in the mouse gastric strips through VIP release

Glucagon-like peptide-2 (GLP-2) has been reported to indirectly relax gastric smooth muscle. In the present study we investigated, through a combined mechanical and immunohistochemical approach, whether GLP-2 interferes with the electrical field stimulation (EFS)-induced vipergic relaxant responses and the mechanism through which it occurs. For functional experiments, strips from the mouse gastric fundus were mounted in organ baths for isometric recording of the mechanical activity. Vasoactive intestinal peptide (VIP) immunoreactivity in GLP-2 exposed specimens was also evaluated by immunohistochemistry. In carbachol pre-contracted strips, GLP-2 (20 nM) evoked a tetrodotoxin (TTX)-sensitive relaxation, similar in shape to the TTX-insensitive of 100 nM VIP. In the presence of GLP-2, VIP had no longer effects and no more response to GLP-2 was observed following VIP receptor saturation. EFS (4–16 Hz) induced a fast relaxant response followed, at the higher stimulation frequencies (≥ 8 Hz), by a slow one. This latter was abolished either by GLP-2 or VIP receptor saturation as well as by the VIP receptor antagonist, VIP 6–28 (10 μM). A decrease of VIP-immunoreactive nerve structures in the GLP-2 exposed specimens was observed. These results suggest that, in the mouse gastric fundus, GLP-2 influences the EFS-induced slow relaxant response by promoting neuronal VIP release.

Characterization of projections of longitudinal muscle motor neurons in human colon.

The enteric nervous system contains inhibitory and excitatory motor neurons which modulate smooth muscle contractility. Cell bodies of longitudinal muscle motor neurons have not been identified in human intestine. We used retrograde tracing ex vivo with DiI, with multiple labeling immunohistochemistry, to characterize motor neurons innervating tenial and inter-tenial longitudinal muscle of human colon. The most abundant immunohistochemical markers in the tertiary plexus were vesicular acetylcholine transporter, nitric oxide synthase (NOS), and vasoactive intestinal polypeptide (VIP). Of retrogradely traced motor neurons innervating inter-tenial longitudinal muscle, 95% were located within 6mm oral or anal to the DiI application site. Excitatory motor neuron cell bodies, immunoreactive for choline acetyltransferase (ChAT), were clustered aborally, whereas NOS-immunoreactive cell bodies were distributed either side of the DiI application site. Motor neurons had small cell bodies, averaging 438+18µm2 in cross-sectional area, similar for ChAT- and NOS-immunoreactive subtypes. Motor neurons innervating the tenia had slightly longer axial projections, with 95% located within 9mm. ChAT-immunoreactive excitatory motor neurons to tenia were clustered aborally, whereas NOS-immunoreactive inhibitory motor neurons had both ascending and descending projections. VIP immunoreactivity was rarely present without NOS immunoreactivity in motor neurons. Tenial and inter-tenial motor neurons innervating the longitudinal muscle have short projections. Inhibitory motor neurons have less polarized projections than cholinergic excitatory motor neurons. Longitudinal and circular muscle layers are innervated by distinct local populations of excitatory and inhibitory motor neurons. A population of human enteric neurons that contribute significantly to colonic motility has been characterized.

Preferential inputs from cholecystokinin-positive neurons to the somatic compartment of parvalbumin-expressing neurons in the mouse primary somatosensory cortex

Parvalbumin-positive (PV+) neurons in the cerebral cortex, mostly corresponding to fast-spiking basket cells, have been implicated in higher-order brain functions and psychiatric disorders. We previously demonstrated that the somatic compartment of PV+ neurons received inhibitory inputs mainly from vasoactive intestinal polypeptide (VIP)+ neurons, whereas inhibitory inputs to the dendritic compartment were derived mostly from PV+ and somatostatin (SOM)+ neurons. However, a substantial number of the axosomatic inputs have remained unidentified. Here we show preferential innervation of the somatic compartment of PV+ neurons by cholecystokinin (CCK)+ neurons in the mouse primary somatosensory cortex. CCK+ neurons, a minor population of GABAergic neurons (3.2%), displayed no colocalization with PV or SOM immunoreactivity but partial overlap with VIP immunoreactivity (27.7%). Confocal laser scanning microscopy observation of CCK+ synaptic inputs to PV+ neurons revealed that CCK+ neurons preferred the somatic compartment to the dendritic compartment of PV+ neurons and provided approximately 33% of the axosomatic inhibitory inputs to PV+ neurons. Additionally, 20.9% and 12.1% of the axosomatic inputs were derived from CCK+/VIP+ and CCK+/VIP-negative (−) neurons, presumably double bouquet and large basket cells, respectively. Furthermore, the densities of the axosomatic inputs from CCK+ and/or VIP+ neurons to PV+ neurons were not significantly different among the cortical layers. The present findings suggest that, by preferentially innervating the cell bodies of PV+ neurons, both CCK+/VIP− basket and CCK+/VIP+ double bouquet cells might efficiently interfere with action potential generation of PV+ neurons, and that the two types of CCK+ neurons might have a large impact on cortical activity through PV+ neuron inhibition.

Morphological and neurochemical differences in peptidergic nerve fibers of the mouse vagina.

The vagina is innervated by a complex arrangement of sensory, sympathetic, and parasympathetic nerve fibers that contain classical transmitters plus an array of neuropeptides and enzymes known to regulate diverse processes including blood flow and nociception. The neurochemical characteristics and distributions of peptide-containing nerves in the mouse vagina are unknown. This study used multiple labeling immunohistochemistry, confocal maging and analysis to investigate the presence and colocalization of the peptides vasoactive intestinal polypeptide (VIP), calcitonin-gene related peptide (CGRP), substance P (SP), neuropeptide tyrosine (NPY), and the nitric oxide synthesizing enzyme neuronal nitric oxide synthase (nNOS) in nerve fibers of the murine vaginal wall. We compared cervical and vulvar areas of the vagina in young nullipara and older multipara C57Bl/6 mice, and identified differences including that small ganglia were restricted to cervical segments, epithelial fibers were mainly present in vulvar segments and most nerve fibers were found in the lamina propria of the cervical region of the vagina, where a higher number of fibers containing immunoreactivity for VIP, CGRP, SP, or nNOS were found. Two populations of VIP-containing fibers were identified: fibers containing CGRP and fibers containing VIP but not CGRP. Differences between young and older mice were present in multiple layers of the vaginal wall, with older mice showing overall loss of innervation of epithelium of the proximal vagina and reduced proportions of VIP, CGRP, and SP containing nerve fibers in the distal epithelium. The distal vagina also showed increased vascularization and perivascular fibers containing NPY. Immunolabeling of ganglia associated with the vagina indicated the likely origin of some peptidergic fibers. Our results reveal regional differences and age- or parity-related changes in innervation of the mouse vagina, effecting the distribution of neuropeptides with diverse roles in function of the female genital tract.

Downregulation of neuronal vasoactive intestinal polypeptide in Parkinson's disease and chronic constipation.

Chronic constipation (CC) is a common and severe gastrointestinal complaint in Parkinson's disease (PD), but its pathogenesis remains poorly understood. This study evaluated functionally distinct submucosal neurons in relation to colonic motility and anorectal function in PD patients with constipation (PD/CC) vs both CC and controls. Twenty-nine PD/CC and 10 Rome III-defined CC patients were enrolled. Twenty asymptomatic age-sex matched subjects served as controls. Colonic transit time measurement and conventional anorectal manometry were evaluated in PD/CC and CC patients. Colonoscopy was performed in all three groups. Colonic submucosal whole mounts from PD/CC, CC, and controls were processed for immunohistochemistry with antibodies for vasoactive intestinal polypeptide (VIP) and peripheral choline acetyltransferase, markers for functionally distinct submucosal neurons. The mRNA expression of VIP and its receptors were also assessed. Four subgroups of PD/CC patients were identified: delayed colonic transit plus altered anorectal manometry (65%); delayed colonic transit (13%); altered manometric pattern (13%); and no transit and manometric impairment (9%). There were no differences in the number of neurons/ganglion between PD/CC vs CC or vs controls. A reduced number of submucosal neurons containing VIP immunoreactivity was found in PD/CC vs controls (P<.05). VIP, VIPR1, and VIPR2 mRNA expression was significantly reduced in PD/CC vs CC and controls (P<.05). Colonic motor and rectal sensory functions are impaired in most PD/CC patients. These abnormalities are associated with a decreased VIP expression in submucosal neurons. Both sensory-motor abnormalities and neurally mediated motor and secretory mechanisms are likely to contribute to PD/CC pathophysiology.

Distribution and Origin of VIP-, SP-, and Phospholipase Cβ2 -Immunoreactive Nerves in the Tongue of the Bullfrog, Rana catesbeiana.

Previous studies have found a few intralingual ganglionic cells that were immunoreactive to vasoactive intestinal polypeptide (VIP) in the frog. A recent study reported a large number of such cells, and the possibility of the release of substance P (SP) from these. The aim of the present study was to investigate the distribution, origin, and colocalization of VIP- and SP- immunoreactive nerves in the tongue of the bullfrog, R. catesbeiana. In addition, the study also examined the colocalization of SP and phospholipase Cβ2 (PLCβ2 ) in the tongue and jugular ganglion. VIP immunoreactivity was seen in unipolar cells that were sparse in nerve bundles in the submucosal and muscle layers. The density of VIP-immunoreactive cells was approximately 4.8 cells/mm(3) . Their fibers terminated in the vicinity of the epithelial basal layer of the fungiform papillae. SP immunoreactivity was not seen in the VIP-immunoreactive cells, but was observed in pseudounipolar cells in the jugular ganglion. The SP fibers terminated close to the free surface, showing spindle- and button-like profiles. Transection of glossopharyngeal nerve resulted in the persistence of VIP-immunoreactive cells and the disappearance of SP-immunoreactive fibers in the tongue. SP immunoreactivity was co-expressed with PLCβ2 in both the tongue and jugular ganglia. No PLCβ2 immunoreactivity was seen in cells comprising the epithelial taste disk. These findings indicate that the origin of VIP nerve fibers are unipolar cells in the tongue, and SP and PLCβ2 fibers originate from pseudounipolar cells that may be able to release SP primarily in the jugular ganglion. Anat Rec, 299:929-942, 2016. © 2016 Wiley Periodicals, Inc.

Changes in brain peptides associated with reproduction and energy homeostasis in photosensitive and photorefractory migratory redheaded buntings

Present study examined the expression of brain peptides associated with the reproduction and energy homeostasis (GnRH/GnIH, NPY/VIP), and assessed their possible functional association in the photosensitive (non-breeding, pre-breeding), photostimulated (breeding) and photorefractory (post-breeding) migratory redheaded buntings (Emberiza bruniceps), using double-labeled immunohistochemistry. Particularly, we measured immunoreactive (-ir) cell numbers, per cent cell area and cell optical density (OD) in the preoptic area (GnRH-I), midbrain (GnRH-II), paraventricular nucleus (GnIH), dorsomedial hypothalamus, DMH and infundibular complex, INc (NPY and VIP), and lateral septal organ (VIP) of buntings kept under natural photoperiods at the wintering latitude (26°55′N). There was a significant seasonal difference in GnRH-I, not GnRH-II, with reduced -ir cells in the photosensitive and photorefractory buntings, and notably with increased cell OD between the refractory and non-breeding states with no increase in testis size. Also, increased cell OD of GnIH neurons in non-breeding state indicated its role in the maintenance of small testes during the post-refractory period. Overall, seasonal changes in GnRH-I and GnIH were found consistent with their suggested roles in reproductive regulation of absolute photorefractory birds. Further, there was a significant seasonal change in cell OD of NPY neurons in DMH, not the INc. In contrast, VIP immunoreactivity was seasonally altered, with a significantly higher VIP-ir cells in breeding than the pre-breeding state. Finally, close proximity between perikarya with fibres suggested functional interactions between the GnRH and GnIH, and NPY and VIP. Thus, seasonal plasticity of brain peptides is perhaps the part of neural regulation of seasonal reproduction and associated energy homeostasis in migratory songbirds.

Surgical resection of vasoactive intestinal peptideoma with hepatic metastasis aids symptom palliation: A case report.

Vasoactive intestinal peptideoma (VIPoma) is a rare pancreatic endocrine tumor associated with a well-defined clinical syndrome characterized by watery diarrhea, hypokalemia and metabolic acidosis. In adults, VIPoma is most commonly found in the pancreas, with 80% of the tumors occurring in the body and tail and 20% occurring in the pancreatic head. VIPomas can represent a significant diagnostic challenge due to their nonspecific clinical presentation, which can result in the misdiagnosis of a VIPoma as another condition, such as laxative overdose or a carcinoid secreting tumor. Surgical clearance of the tumor is the first-line treatment, even in cases with metastasis. The present study describes the case of a patient who presented with chronic watery diarrhea and hypokalemia due to a tumor in the pancreatic head, which was confirmed to contain immunoreactive vasoactive intestinal polypeptide via immunohistochemistry. A hepatic metastasis lesion was diagnosed following computed tomography. Stable control of symptoms was achieved after surgery and drug treatment. The study additionally reviews the clinical, histological, radiological and diagnostic features of the condition, as well as the therapeutic modalities that can be used to treat VIPoma in the pancreatic head with hepatic metastasis.

Immunohistochemical localization of vasoactive intestinal peptide in bursa of fabricius of Chinese yellow quail

This study aimed to reveal the distribution and morphological characteristics of vasoactive intestinal peptide (VIP) at different ages in the bursa of Fabricius (BF) in Chinese Yellow Quail. The distribution and morphological characteristics of VIP of BF in Chinese yellow quails at different ages (0, 1, 3, 5, 9, 13, 17, 21, 25, 29, 32 and 36 weeks) were observed using the immunohistochemical streptavidin-biotin complex method after obtaining the sections and subsequent immunohistochemical staining. Then semi-quantitative analysis of the mean optical density (MOD), integral optical density (IOD) and mean gray value (MGV) for VIP immunoreactivity was performed through Image-Pro Plus 6.0 software. VIP was observed at all ages in Chinese yellow quail’s BF. It formed a long fusiform, oval or granular type structures with clear outline mainly localized in the submucosa, muscular layer and serosal connective tissue. At 25 weeks of age, the MOD value of VIP-positive cells reached the maximum, and then gradually reduced, while the MGV value was the lowest. We observed the localization and morphological characteristics of VIP in BF of Chinese yellow quail. VIP was mainly localized in the submucosa, muscular layer and serosal connective tissue of BF. Findings of this study may provide further understanding of the function of VIP in BF of Chinese yellow quails.

Influence of renovascular hypertension on the distribution of vasoactive intestinal peptide in the stomach and heart of rats.

Arterial hypertension is associated with serious dysfunction of the cardiovascular system and digestive system. Given the relevant role of vasoactive intestinal peptide (VIP) in the regulation of digestion process, control of blood pressure and heart rate as well as cardio- and gastro-protective character of the peptide, it appeared worthwhile to undertake the research aimed at immunohistochemical identification and evaluation of VIP-positive structures in the pylorus and heart of hypertensive rats. Up to now, this issue has not been investigated. The experimental model of hypertension in rats according to Goldblatt (two-kidney one clip model of hypertension) was used in the study. The experimental material (pylorus and heart) was collected in the sixth week of the study. VIP-containing structures were evaluated using immunohistochemical and morphometric methods. The analysis of the results showed a significant increase in the number of immunoreactive VIP structures and in the intensity of immunohistochemical staining in the stomach and in the heart of hypertensive rats. Our findings indicate that VIP is an important regulator of cardiovascular and digestive system in physiological and pathological conditions. However, to better understand the exact role of VIP in hypertension further studies need to be carried out.

Seasonal plasticity in the peptide neuronal systems: potential roles of gonadotrophin-releasing hormone, gonadotrophin-inhibiting hormone, neuropeptide Y and vasoactive intestinal peptide in the regulation of the reproductive axis in subtropical Indian weaver birds.

Two experiments examined the expression of gonadotrophin-releasing and inhibiting hormones (GnRH-I, GnRH-II and GnIH), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) in subtropical Indian weaver birds, which demonstrate relative photorefractoriness. Experiment 1 measured peptide expression levels in the form of immunoreactive (-IR) cells, percentage cell area and cell optical density in the preoptic area (GnRH-I), midbrain (GnRH-II), paraventricular nucleus (GnIH), mediobasal hypothalamus [dorsomedial hypothalamus (DMH), infundibular complex (INc), NPY and VIP] and lateral septal organ (VIP) during the progressive, breeding, regressive and nonbreeding phases of the annual reproductive cycle. GnRH-I was decreased in the nonbreeding and VIP was increased in INc in the breeding and regressive states. GnRH-II and NPY levels did not differ between the testicular phases. Double-labelled immunohistochemistry (IHC) revealed a close association between the GnRH/GnIH, GnRH/NPY, GnRH/VIP and GnIH/NPY peptide systems, implicating them interacting and playing roles in the reproductive regulation in weaver birds. Experiment 2 further measured these peptide levels in the middle of day and night in weaver birds that were maintained under short days (8 : 16 h light /dark cycle; photosensitive), exposed to ten long days (16 : 8 h light /dark cycle; photostimulated) or maintained for approximately 2 years on a 16 : 8 h light /dark cycle (photorefractory). Reproductively immature testes in these groups precluded the possible effect of an enhanced gonadal feedback on the hypothalamic peptide expression. There were group differences in the GnRH-I (not GnRH-II), GnIH, NPY and VIP immunoreactivity, albeit with variations in immunoreactivity measures in the present study. These results, which are consistent with those reported in birds with relative photorefractoriness, show the distribution and possibly a complex interaction of key neuropeptides in the regulation of the annual reproductive cycle in Indian weaver birds.