Localization Of Vasoactive Intestinal Peptide Research Articles

Localization of vasoactive intestinal peptide and toll-like receptor 2 immunoreactive cells in endostyle of urochordate Styela plicata (Lesueur, 1823).

The endostyle is the first component of the ascidian digestive tract, it is shaped like a through and is located in the pharynx's ventral wall. This organ is divided longitudinally into nine zones that are parallel to each other. Each zone's cells are physically and functionally distinct. Support elements are found in zones 1, 3, and 5, while mucoproteins secreting elements related to the filtering function are found in zones 2, 4, and 6. Zones 7, 8, and 9, which are located in the lateral dorsal section of the endostyle, include cells with high iodine and peroxidase concentrations. Immunohistochemical technique using the following antibodies, Toll‐like receptor 2 (TLR‐2) and vasoactive intestinal peptide (VIP), and lectin histochemistry (WGA—wheat‐germagglutinin), were used in this investigation to define immune cells in the endostyle of Styela plicata (Lesueur, 1823). Our results demonstrate the presence of immune cells in the endostyle of S. plicata, highlighting that innate immune mechanisms are highly conserved in the phylogeny of the chordates.Research highlights Immune cells positive to TLR‐2 and VIP in the endostyle of Styela plicata.Expression of WGA in several zones of endostyle.Use of comparative biology to improve the knowledge about immunology in ascidians.

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.

Nuclear localization of vasoactive intestinal peptide (VIP) receptors in human breast cancer

Vasoactive intestinal peptide (VIP) and its receptors (VPACs) are involved in proliferation, survival, and differentiation in human breast cancer cells. Its mechanism of action is traditionally thought to be through specific plasma membrane receptors. There is compelling evidence for a novel intracrine mode of genomic regulation by G-protein-coupled receptors (GPCRs) that implies both endocytosis and nuclear translocation of peripheral GPCR and/or the activation of nuclear-located GPCRs by endogenously-produced, non-secreted ligands. Regarding to VPAC receptors, which are GPCRs, there is only a report suggesting them as a dynamic system for signaling from plasma membrane and nuclear membrane complex. In this study, we show that VPAC 1 receptor is localized in cell nuclear fraction whereas VPAC 2 receptor presents an extranuclear localization and its protein expression is lower than that of VPAC 1 receptor in human breast tissue samples. Both receptors as well as VIP are overexpressed in breast cancer as compared to non-tumor tissue. Moreover, we report the markedly nuclear localization of VPAC 1 receptors in estrogen-dependent (T47D) and independent (MDA-MB-468) human breast cancer cell lines. VPAC 1 receptors are functional in plasma membrane and nucleus as shown by VIP stimulation of cAMP production in both cell lines. In addition, VIP increases its own intracellular and extracellular levels, and could be involved in the regulation of VPAC 1-receptor traffic from the plasma membrane to the nucleus. These results support new concepts on function and regulation of nuclear GPCRs which could have an impact on development of new therapeutic drugs.

Organization of vasoactive intestinal peptide-like immunoreactive system in the brain, olfactory organ and retina of the zebrafish, Danio rerio, during development

The localization of vasoactive intestinal peptide (VIP)-like immunoreactivity was investigated in the brain, olfactory system and retina of the zebrafish, Danio rerio, during development and in juvenile specimens, by using the indirect immunofluorescence and the peroxidase-antiperoxidase methods. In 24 h post fertilization (hpf) embryos, VIP-like immunoreactive cells were present in the olfactory pit, the retina, and several regions of the brain, including the dorsal telencephalon, the diencephalon, the tegmentum of the mesencephalon, the caudal rhombencephalon and the anterior pituitary. In 48 hpf embryos, additional VIP-like immunoreactive cell bodies were found in the ventral telencephalon, whereas in the diencephalon VIP-like immunopositive cells were more concentrated within the ventro-caudal hypothalamus. During the 7 day larval period, a dense plexus of VIP-like immunoreactive fibers first appeared in the olfactory bulbs. In 15-day-old larvae, two new groups of positive cells were observed in the periventricular preoptic nucleus and in the dorsal rhombencephalon. In 1 month/2 months old animals, VIP-like immunoreactive elements were confined to the olfactory organ, the olfactory bulbs, the periventricular preoptic nucleus and the pituitary, pars distalis. At 3 months stage, a large number of cells was observed in the periventricular preoptic nucleus. Western immunoblot analysis confirmed that VIP-like peptides, with molecular weight similar to that of synthetic VIP, are present early during the development of zebrafish. These results show that VIP-like immunoreactive structures appear early during ontogeny both in the olfactory pit, retina and brain. Transient expression of positive cells was found in the retina, telencephalon, diencephalon and brainstem. The location of VIP-like immunoreactivity indicates that, during development, VIP could be involved in several neuromodulatory functions, including the processing of visual and olfactory informations, as well as growth or survival promotion activities. The presence of VIP-like immunopositive cells in the pituitary, pars distalis, suggest that, during development, VIP may influence the secretion of pituitary hormones.

Distribution of vasoactive intestinal peptide-like immunoreactivity in the brain and pituitary of the frog ( Rana esculenta) during development

The localization of vasoactive intestinal peptide (VIP)-like immunoreactive (ir) elements was investigated in the brain of the anuran amphibian, Rana esculenta, during development. Using an antiserum raised against the porcine VIP, ir cell bodies and fibers were observed in the forebrain of tadpoles a few days after hatching. During early premetamorphosis, ir perikarya were distributed in the ventral infundibular nucleus of the hypothalamus and in the posterocentral nucleus of the thalamus. Labeled fibers were detected in the olfactory bulbs and in the hypothalamus. In these larvae, furthermore, several VIP-ir cells were found in the pars distalis of the pituitary and there were ir fibers in the pars nervosa. In tadpoles at stages VIII–IX, a new group of VIP-labeled neurons was observed in the dorsal part of the infundibular nucleus. In other brain regions, the distribution of the immunoreactivity was similar to that described in the earliest stages, i.e., IV–VII. During mid-premetamorphosis, stages X–XII of development, an additional set of ir perikarya appeared in the ventrolateral area of the thalamus. During late premetamorphosis, stages XIII–XVIII, the organization of VIP-like immunoreactivity was more complex and its distribution more widespread. Two new groups of ir cell bodies appeared, one in the preoptic nucleus and another in the anteroventral area of the thalamus, and for the first time, VIP immunoreactivity was observed in the median eminence. This distribution pattern persisted through to the prometamorphic, four-limb stage. Strikingly, no VIP-ir elements were observed anywhere in the mid- and hindbrain. The present results indicate that a VIP-like ir peptide may be involved in the processing of olfactory information or may act as a neurohormone, hypophysiotropic factor, and neuromodulator in the brain of R. esculenta during development.

The Localization of Vasoactive Intestinal Peptide (VIP)-Like Immunoreactivity in Gonadotropes of the Rat Anterior Pituitary

Abstract The anterior pituitary gland has recently been shown to contain a number of bioactive peptides other than inherent pituitary hormones. One of these peptides is vasoactive intestinal peptide (VIP). The localization of VIP has not known and so the present study was undertaken to determine which type of pituitary cell contains this peptide. The adult rat anterior pituitary was immunohistochemically examined with two VIP antisera. One of these antisera successfully stained some pituitary cells. Both the double immunostaining technique and the flip-flop section method revealed VIP-like immunoreactivity, mainly in gonadotropes. This immunostaining was lost when the anti-VIP was preabsorbed with synthetic VIP or with pituitary adenyl cyclase activating peptide (PACAP), 68% of the 1–28 portion of which is homologous to VIP. When tested with anti-PACAP, however, no immunoreactivity was observed in anterior pituitary tissue. These results indicate that VIP is localized in gonadotropes in the anterior pitui...

The cellular localization of vasoactive intestinal peptide (VIP) in the mouse median eminence by immuno-electron microscopy

The aim of this study was to examine, by use of pre-embedding immunocytochemistry, the ultrastructural localization of vasoactive intestinal peptide (VIP) immunoreactivity in the mouse median eminence. VIP immunoreactivity was observed in axonal profiles. The VIP-immunoreactive axonal profiles were in close proximity to non-immunoreactive axonal profiles that contained dense granular vesicles and clear vesicles and also to processes of tanycytes. VIP-immunoreactive terminals were observed in the proximity of the perivascular space and in the neuropil. Our results suggest that VIP-immunoreactive axon terminals may possibly interact with other non-immunoreactive axon terminals containing peptide and/or other transmitters at the level of the median eminence or may be released to the portal vasculature thereby to effect anterior pituitary cells.

Immunocytochemical Localization of Vasoactive Intestinal Peptide and Neuropeptide Y in the Bovine Ovary

The distribution of the neuropeptides vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) was studied immunocytochemically in bovine ovaries from 3 mo of gestation up to and including puberty, and from adult cows at three stages of the estrous cycle. The appearance of VIP and NPY immunoreactivity of 4.5-6 mo of gestation coincided with the onset of follicular development. In contrast to NPY, VIP was first found in the cortex. Both VIP and NPY immunoreactivity increased with age. From 9 mo of gestation onwards, VIP and NPY were found around blood vessels and non-vascular smooth muscle cells, in the stroma near preantral follicles, and in the theca externa of antral follicles. In addition, VIP-positive cells were observed exclusively in the granulosa layer of the preovulatory follicle at the time of the LH surge. The distribution of VIP- and NPY-immunoreactive fibers in the ovary may point to an effect of these neuropeptides on various physiological processes, including follicle development and ovarian blood flow. In addition, the presence of VIP-positive cells in the granulosa layer of the preovulatory follicle is indicative of a role for VIP in ovulation.

Localization of vasoactive intestinal peptide (VIP) messenger RNA (mRNA) in amacrine cells of rat retina.

We detected vasoactive intestinal peptide (VIP) messenger RNA (mRNA) in the rat retina using an in situ hybridization technique and a 35S-labelled cDNA probe. VIP mRNA was present in the cells of the inner nuclear layer (INL). The VIP mRNA-positive cells showed a distribution similar to that of the VIP-like immunoreactive amacrine cells. This observation suggests that VIP mRNA undergoes transcription in the VIP-immunoreactive amacrine cells.

Autoradiographic characterization and localization of vasoactive intestinal peptide bindign sites in albino rat and rabbit eyes

Localization and pharmacological properties of vasoactive intestinal peptide (VIP) binding sites were investigated in eyes from albino rabbits and rats using an in vitro autoradiographic method. [125I]VIP was used as ligand, and various unlabelled peptides were studied to test the specificity of binding. Autoradiograms were generated by apposing 20-microns-thick cryostat eye sections to [3H]Hyperfilm or autoradiographic emulsion and quantified by means of image analysis procedures. Specific binding represented about 85% of total binding. Kinetic studies showed that equilibrium was reached after a 120-min incubation at room temperature. Biochemical investigations demonstrated that [125I-]VIP bound to a population of sites with high affinity (Kd = 2.27 +/- 0.25 nM). Inhibition of [125I]VIP binding with VIP and related peptides indicated the following rank order of potency: VIP greater than Peptide histidine isoleucine greater than secretin greater than human growth hormone-releasing factor, glucagon, VIP1-14, VIP14-28. In both species, specific binding was found in conjunctiva, iris, ciliary processes, choroid and retina. Moderate grain densities of VIP binding sites were also present in the rat cornea. Quantitative analysis of the autoradiograms revealed that the highest densities of [125I]VIP binding sites were located in the iris and ciliary epithelia in rabbits and in the inner retina in rats. Our findings suggest that VIP may play an important role in several ocular functions, especially in aqueous humor dynamics and retinal neuromodulation.

Localization of vasoactive intestinal peptide binding sites in the thymus and bursa of Fabricius of the chick

The purpose of this study was to determine the distribution of VIP binding sites in the thymus and bursa of Fabricius using receptor binding and autoradiographic techniques. Biochemical characterization of 125I-VIP binding sites determined two classes of specific binding sites in both tissues. The dissociation constants determined in the thymus were 1.12 nM and 88.5 nM, and in the bursa were 0.459 nM and 70.8 nM. Autoradiographic localization of 125I-VIP binding sites within the thymus demonstrated specific binding associated with the medullary region of the thymic lobule and the blood vessels in the interlobular and trabecular areas. Within the bursa of Fabricius, high densities of silver grains corresponded with vascular elements in the interfollicular regions, the epithelial border of the plicae, the muscular layer surrounding the organ, and the diffusely infiltrated area near the burso-cloacal duct.

Role of the vasoactive intestinal peptide in a neuroendocrine regulation of the adrenal cortex.

Using a method for isolation and perfusion of pig adrenal glands with preserved nerve supply, we measured the release of cortisol and aldosterone and of the vasoactive intestinal peptide (VIP) after electrical stimulation of the splanchnic nerves. Additionally, the effect of VIP (at final concentrations of 10(-10)-10(-7) M) in the perfusion medium on the release of cortisol and aldosterone was investigated. The amount of VIP contained within the adrenal was measured by chromatography, and the localization of VIP in the adrenal gland was investigated immunohistochemically. Stimulation of the splanchnic nerves provoked a significant release of VIP (2.7- to 17-fold) and of the corticosteroids cortisol (2.5- to 6.7-fold) and aldosterone (1.6- to 2.8-fold). VIP added to the perfusion medium stimulated secretion of both corticosteroids with a maximal effect at 10(-8) M. Cortisol release increased 20- to 58.5-fold over basal, aldosterone release increased 2.9- to 4.9-fold over basal. This VIP-stimulated release had the same range of magnitude as the release stimulated by adrenocorticotropic hormone in physiological concentrations (10(-10) M). The mean concentration of VIP-like immunoreactivity in the adrenal glands was 8.9 +/- 2.1 pmol/g wet weight. Immunohistochemical investigations showed immunoreactive cells within the adrenal medulla as well as VIP-ergic nerve fibers in the cortex of the adrenal gland. These data show that the adrenal cortex can be stimulated independent of the hypothalamus-pituitary-adrenal axis via a neuroadrenocortical axis. In this regulatory pathway, the VIP-ergic innervation of the adrenal cortex may be a potent stimulatory element.

Localization of vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivities in the rat superior cervical ganglion and its nerve trunks.

Electrical stimulation of the preganglionic cervical sympathetic trunk causes an increase in dopa synthesis in the postganglionic neurons in the superior cervical ganglion (SCG). This transsynaptic biochemical effect can be blocked only partially by cholinergic antagonists, suggesting the involvement of a noncholinergic preganglionic sympathetic neurotransmitter(s). A survey of a large number of possible candidates for this neurotransmitter revealed that, in addition to cholinergic agonists, only a small group of peptides (all members of the secretin-glucagon family) stimulated dopa synthesis in the SCG. The effective peptides included vasoactive intestinal peptide (VIP), peptide histidine isoleucine amide (PHI), and secretin. Consequently we looked for the presence of immunoreactivities for these three peptides in the SCG. VIP- and PHI-like immunoreactive fibers were found in the SCG and in its major pre- and postganglionic nerve trunks. The distributions of the two immunoreactivities were very similar. Immunoreactive fibers were seen both singly and in bundles. In some instances, fibers were found apposed to neuronal cell bodies in the ganglion, and occasionally dense plexuses of fibers were found surrounding the neurons. In addition, punctate immunoreactive profiles were found apposed to the neurons in what appeared to be terminal fields. A small number of immunoreactive neuronal cell bodies were also seen in the ganglion. In a few instances, it was possible to establish, in serial sections, that the same cell body was immunostained with both VIP and PHI antisera. No secretin like-immunoreactive fibers or cells were observed. The presence of VIP-like and PHI-like-immunoreactive fibers in the cervical sympathetic trunk and in the SCG strengthens the possibility that these peptides, or a related molecule(s), serve as preganglionic neurotransmitters in this ganglion.

A comparative study of the localization of vasoactive intestinal peptide- and substance P-like immunoreactivities in the submandibular salivary glands of mice.

The localization of vasoactive intestinal peptide (VIP)- and substance P (SP)-like immunoreactivities within the submandibular salivary glands (SMG) of Balb/c male mice at 4 to 5 weeks of age were investigated. Two immunocytochemical methods using polyclonal, monospecific antibodies, the indirect immunofluorescence and peroxidase-antiperoxidase (PAP), were used to elucidate the localization of VIP- and SP-like immunoreactivities in the SMG. Both VIP- and SP-like immunoreactivities were positive in the SMG of Balb/c male mice at 4 to 5 weeks of age. The VIP-like immunoreactivity was found in the dense plexuses around the salivary duct and in the small scattered nerves surrounding glandular acini, and particularly in the nerve cell bodies of the submaxillary ganglion. The SP-like immunoreactivity was conspicuously abundant in the excretory ducts with a rich supply of SP-positive nerves, but also very scanty in the acinus areas close to the striated ducts and interlobular excretory ducts. It could be conclusively observed that the localization of the VIP- and SP-like immunoreactivities were different in the submaxillary ganglion, in the nerves around blood vessels and acinus areas, but very similar in the areas of the excretory and striated duct of the SMG.

Immunohistochemical localization of vasoactive intestinal peptide (VIP) in the circumventricular organs of the rat.

The indirect peroxidase-antiperoxidase immunohistochemical technique was used to investigate the possible presence of vasoactive intestinal peptide (VIP) in the circumventricular organs of the rat. Considerable numbers of VIP-immunoreactive fibers were seen in the pineal gland. A moderate amount of VIP-immunoreactive fibers was present in the median eminence, the posterior lobe of the pituitary and the area postrema, but only few fibers were found in the organum vasculosum laminae terminalis. No immunoreactivity was observed in the subfornical organ or the subcommissural organ. The circumventricular organs investigated were completely free of VIP-immunoreactive perikarya. In the circumventricular organs, VIP-immunoreactive fibers were visible between the parenchymal cells and in the perivascular spaces. The presence of coarse VIP-immunoreactive terminals in apposition to the portal vessels in the external layer of the median eminence indicates that VIP may be secreted directly into the pituitary portal circulation, thus influencing the anterior pituitary cells. The presence of large VIP-immunoreactive boutons in the posterior lobe of the pituitary suggests a secretion of VIP directly into the systemic circulation. In the pineal gland, a dense innervation by VIP-immunoreactive fibers was found in the peripheral superficial part of organ, with fibers penetrating into its central portion where they mainly terminate near in vicinity of the capillaries. In the area postrema, VIP-immunoreactive material was mainly found at the ventral border of the organ. In addition to the secretion of VIP into the bloodstream via the circumventricular organs, this study provides evidence that VIP exerts specific influence on the cellular elements of these organs.

Localization of vasoactive intestinal peptide and peptide histidine isoleucine immunoreactivity and mRNA within the rat suprachiasmatic nucleus

The distribution of vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) mRNA within the suprachiasmatic nucleus (SCN) of rats was evaluated by immunocytochemistry and in situ hybridization. The pattern of VIP and PHI immunoreactivity corresponded closely to the distribution of VIP/PHI mRNA within the ventrolateral SCN. Clear hybridization signal was observed within the SCN of rats killed 5 h after light onset and in rats killed 2 h after the onset of the dark phase of the light-dark cycle. Visual examination of the grain density within the autoradiographs suggested that VIP/PHI mRNA may occur in higher concentrations shortly after the onset of darkness than 5 h after the onset of the light phase.

Immunohistochemical Localization of Vasoactive Intestinal Peptide in the Dogfish Rectal Gland

Immunohistochemical Localization of Vasoactive Intestinal Peptide in the Dogfish Rectal Gland

Selective localization of vasoactive intestinal peptide and substance P in human eosinophils

Extracts of purified human eosinophils had a mean concentration of 72 fmol of immunoreactive vasoactive intestinal peptide and 21 fmol of substance P per 10(7) eosinophils, that were significantly higher than the content of immunoreactivity of the same neuropeptides in neutrophils, mononuclear leukocytes, and platelets. In contrast, the lower concentrations of calcitonin gene-related peptide and somatostatin were similar in extracts of all leukocytes. Chromatography of the peptides from eosinophils confirmed their identity with vasoactive intestinal peptide and substance P from neuroendocrine sources. Stores of some neuropeptides may endow eosinophils with unique roles in host defense and hypersensitivity reactions.

Autoradiographic localization of vasoactive intestinal peptide (VIP) binding sites in the human term placenta. Relationship with activation of adenylate cyclase

The presence of vasoactive intestinal peptide (VIP) binding sites and the adenylate cyclase activity in response to VIP were examined in the human term placenta. Slices were used in order to preserve the physicochemical environment and the structural integrity of this heterogeneous organ. 125I-VIP binding to placental slices was saturable. The steady state was reached after 90 min at 37°C and was maintained up to 3 h. Unlabeled VIP was able to compete in a dose-dependent manner with an IC 50 value of 5.2 ± 1.3 × 10 −10 M. Autoradiography and histological analysis showed that VIP binding sites were essentially located on fetal vascularization, especially arteries of stem villi. VIP produced a stimulatory effect on cAMP synthesis at a concentration as low as 10 −10 M. The dose-response curve was monophasic with an ED 50 value of 2.9 ± 1.6 × 10 −9 M. The specificity of the VIP effect was tested with peptides structurally related to VIP such as glucagon, secretin, gastric inhibitory polypeptide and human growth-hormone releasing factor. Only secretin at high concentrations (> 10 −6 M) increased cAMP production. Leu-enkephalin or insulin were ineffective. The presence of both VIP binding sites on fetal vascularization and VIP-induced adenylate cyclase activation would seem to suggest a regulatory role of the peptide on fetoplacental blood flow.

Structure and expression of the gene encoding the vasoactive intestinal peptide precursor.

The gene encoding the human vasoactive intestinal peptide (VIP) and the histidine-methionine amide (PHM-27) peptide hormone was isolated from lambda phage libraries. The human gene was found to be composed of seven exons spanning approximately 9 kilobase pairs. The first exon codes for an untranslated leader sequence, and the second exon codes for a putative signal peptide. DNA sequences coding for the VIP and PHM-27 hormones are located in two different exons. Southern blot analysis with genomic DNA suggested that a single copy of the VIP/PHM-27 gene is present in the human haploid genome. The expression of VIP/PHM-27 precursor mRNA in various tissues in the rat was analyzed by RNA gel blot hybridization. In the organs examined, expression was only detected in the brain and duodenum. RNA isolated from various regions of the rat brain--including the cortex, hypothalamus, and hippocampus--hybridized to both VIP- and PHM-27-specific probes. The same pattern of hybridization was found when VIP- and PHM-27-specific probes were used, suggesting that possible differences in the localization of VIP and PHM-27 peptides between different brain regions cannot be accounted for by differential RNA processing.