Co-localization Of Vasoactive Intestinal Peptide Research Articles

Effect of Acrylamide Supplementation on the Population of Vasoactive Intestinal Peptide (VIP)-Like Immunoreactive Neurons in the Porcine Small Intestine.

Acrylamide is one of the harmful substances present in food. The present study aimed to establish the effect of acrylamide supplementation in tolerable daily intake (TDI) dose (0.5 µg/kg b.w./day) and a dose ten times higher than TDI (5 µg/kg b.w./day) on the population of vasoactive intestinal peptide-like immunoreactive (VIP-LI) neurons in the porcine small intestine and the degree of the co-localization of VIP with other neuroactive substances (neuronal nitric oxide synthase (nNOS), substance P (SP), and cocaine- and amphetamine-regulated transcript peptide (CART)). In our work, 15 Danish landrace gilts (5 in each experimental group) received capsules (empty or with low or high doses of acrylamide) for a period of 28 days with their morning feeding. Using double immunofluorescence staining, we established that acrylamide supplementation increased the number of neurons showing immunoreactivity towards VIP in all types of enteric nervous system (ENS) plexuses and fragments of the small intestine studied. Moreover, both doses of acrylamide led to changes in the degree of co-localization of VIP with nNOS, SP, and CART in intramural neurons. The observed changes may be the adaptation of neurons to local inflammation, oxidative stress, or the direct toxic effects of acrylamide on intestinal neurons, also referred to as neuronal plasticity.

The orexin system in the enteric nervous system of the bottlenose dolphin (Tursiops truncatus).

This study provides a general approach to the presence and possible role of orexins and their receptors in the gut (three gastric chambers and intestine) of confined environment bottlenose dolphin. The expression of prepro-orexin, orexin A and B and orexin 1 and 2 receptors were investigated by single immunostaining and western blot analysis. The co-localization of vasoactive intestinal peptide and orexin 1 receptor in the enteric nervous system was examined by double immunostaining. Also, orexin A concentration were measured in plasma samples to assess the possible diurnal variation of the plasma level of peptide in this species. Our results showed that the orexin system is widely distributed in bottlenose dolphin enteric nervous system of the all gastrointestinal tract examined. They are very peculiar and partially differs from that of terrestrial mammals. Orexin peptides and prepro-orexin were expressed in the main stomach, pyloric stomach and proximal intestine; while orexin receptors were expressed in the all examined tracts, with the exception of main stomach where found no evidence of orexin 2 receptor. Co-localization of vasoactive intestinal peptide and orexin 1 receptor were more evident in the pyloric stomach and proximal intestine. These data could suggest a possible role of orexin system on the contractility of bottlenose dolphin gastrointestinal districts. Finally, in agreement with several reports, bottlenose dolphin orexin A plasma level was higher in the morning during fasting. Our results emphasize some common features between bottlenose dolphin and terrestrial mammals. Certainly, further functional investigations may help to better explain the role of the orexin system in the energy balance of bottlenose dolphin and the complex interaction between feeding and digestive physiology.

Colocalization of VIP with AVP in neurons of the human paraventricular, supraoptic and suprachiasmatic nucleus

Aim of this study was to investigate, with the aid of a recently developed immunofluorescence technique, cellular colocalization of vasoactive intestinal peptide (VIP) with arginine–vasopressin (AVP) in the paraventricular nucleus (PVN), the supraoptic nucleus (SON) and the suprachiasmatic nucleus (SCN) of the human hypothalamus. To this end, six hypothalami resected from patients who had died suddenly served as material of research. After formaldehyde fixation and subsequent storage in 30% sucrose, 25-μm thick cryosections were cut of one half of each hypothalamus. These sections were double-immunolabeled with primary antibodies against AVP and VIP followed by fluorophore-conjugated secondary antibodies. Autofluorescence, mainly caused by lipofuscin granules in neurons and glial cells, was blocked by a specially developed procedure consisting of incubating the immunolabeled sections in a Sudan Black B solution. Quantitative analysis with a confocal laser scanning microscope showed that of all stained cellular profiles the percentages of profiles immunoreactive exclusively for AVP or VIP or for both neuropeptides (colocalization) were for the SCN approximately 76.5%, 19.6% and 3.9%, for the SON 97.7%, 0.2% and 2.1% and for the PVN 93.2%, 1.6% and 5.2%, respectively. These data illustrate that colocalization between AVP and VIP is not only present in neurons of the PVN and SON, but also in neurons of the SCN. This unexpected finding illustrates that the human SCN may also use a highly differentiated language to transmit its circadian signal to the rest of the brain.

Regional Differences in the Innervation of the Human Ureterovesical Junction by Tyrosine Hydroxylase-, Vasoactive Intestinal Peptide- and Neuropeptide Y-Like Immunoreactive Nerves

We have used double-label immunohistochemistry to examine the presence and pattern of colocalization of vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), tyrosine hydroxylase (TH) and protein gene product (PGP) in nerve fibers supplying the human ureterovesical junction (UVJ). Several populations of nerve fibers within the UVJ region were identified according to their expression of potential transmitter substances. Presumptive noradrenergic axons containing TH- and NPY-like immunoreactivity (LIR) and non-noradrenergic fibers containing VIP-and NPY-LIR accounted for most of the total (PGP-LIR) innervation and supplied all regions of the UVJ. The distal ureter, Waldeyer's sheath and the trigone were supplied by predominantly noradrenergic TH/NPY-LIR nerve fibers, whereas the majority of fibers supplying the detrusor muscle were non-noradrenergic VIP/NPY-LIR axons. The similarity in innervation of Waldeyer's sheath, ureter and trigone is consistent with the notion that these structures are all derived from a common mesodermal origin. Regional differences in innervation were also noted within the musculature of the distal ureter: TH/NPY-LIR fibers were localized to the outer part of the ureter, while VIP/NPY-LIR fibers supplied the inner part. This finding suggests that the different layers of the ureter may be independently controlled by different populations of nerves. The findings of this study support the view that noradrenergic nerves are important in maintaining the tone of the UVJ, but indicate that other neurotransmitters or neuromodulators may also be involved in the control of this region.

Colocalization of neuropeptides and NADPH-diaphorase in the intra-adrenal neuronal cell bodies and fibres of the rat.

Colocalization of vasoactive intestinal peptide, neuropeptide Y, calcitonin gene-related peptide, substance P, and tyrosine hydroxylase, respectively, with NADPH-diaphorase staining in rat adrenal gland was investigated using the double labelling technique. All vasoactive intestinal peptide- and some neuropeptide Y-immunoreactive intrinsic neuronal cell bodies seen in the gland were double stained with NADPH-diaphorase. Double labelling also occurred in some nerve fibres immunoreactive to vasoactive intestinal peptide and neuropeptide Y in the medulla and cortex. No colocalization of calcitonin gene-related peptide, substance P or tyrosine hydroxylase immunoreactivity with NADPH-diaphorase staining was observed. However, nerve fibres with varicosities immunoreactive for all the neuropeptides examined were closely associated with some of the NADPH-diaphorase-stained neuronal cell bodies. Thus, in rat adrenal gland, nitric oxide is synthesized in all ganglion cells containing vasoactive intestinal peptide and in some containing neuropeptide Y, but not in those containing calcitonin gene-related peptide, substance P or tyrosine hydroxylase.

Colocalization of vasoactive intestinal peptide and nitric oxide synthase in neurons of the ferret trachea

Neurally-mediated relaxation of smooth muscle in human, 26 guinea-pig, 7 cat, 14 and pig 18 airways is largely attributed to a nonadrenergic, noncholinergic mechanism. While the specific transmitter(s) of this relaxant system have not been conclusively identified, vasoactive intestinal peptide and nitric oxide have emerged as likely modiators in airway smooth muscle. Both vasoactive intestinal paptide and nitric oxide relax guinea-pig, 3,22,28 pig 18,19 and human 2,24 smooth muscle. Vasoactive intestinal peptide is present in nerve fibers several animal species. 12,13,33 In guinea-pigs, vasoactive intestinal peptide is released during electrical field stimulation of airway strips and the release correlates with the nonadrenergic relaxation. 23 This relaxation is markedly reduced after incubation of tracheal tissue with a specific VIP antibody 13 and by immunization to vasoactive intestinal peptide. 16 Similarly, nonadrenergic relaxations induced by electrical field stimulation are reduced in human, 2,15 pig, 19 guinea-pig 22 and bovine 32 airways by nitric oxide synthesis inhibitors. Vasoactive intestinal peptide is present in nerve cell bodies of airway ganglia, 12,13 suggesting that these nerves in airway smooth muscle originate from intrinsic neurons. 10 It is stored in dense-core vesicles of nerve terminals near airway smooth muscle, 21 suggesting that preformed vasoactive intestinal peptide is released by fusion of the vesicles with the cell membrane of the nerve terminal Nitric oxide is probably generated by a novel mechanism involving de novo synthesis at the nerve terminal during neural activation by the action of the enzyme nitric oxide synthase. 29,30 However, since nitric oxide is also produced by both endothelial cells 17,25 and macrophages, 31 it is important to show that neurons in the airways are capable of producing nitric oxide in order to establish it as a neural mediator. Therefore, we have examined the localization of nitric oxide synthase and its possible colocalization with vasoactive intestinal peptide in the anatomically well characterized plexus of ferret trachea. 1We found that nitric oxide synthase and vasoactive intestinal peptide are present in a subpopulation of nenrons within the plexus, with nerve cell bodies located in specific ganglia and in nerve fibers associated with tracheal smooth muscle and the walls of blood vessels. These findings prove that nitric oxide synthase and vasoactive intestinal peptide are present in the same neurons and that the nerve fibers are processes of motor neurons with nerve cell bodies located in intramural ganglia of the tracheal plexus.

Colocalization of Vasoactive Intestinal Peptide‐ and Substance P‐Containing Nerves in Cat Airwaysa

Colocalization of Vasoactive Intestinal Peptide‐ and Substance P‐Containing Nerves in Cat Airways^a

Co-localization of vasoactive intestinal peptide- and substance P-containing nerves in cat bronchi

The occurrence of vasoactive intestinal peptide (VIP) and substance P in nerve fibers within the lung is well established, and both VIP- and substance P-containing nerve fibers are known to supply pulmonary vascular and bronchial smooth muscle and submucosal glands. In the present study, we have investigated the co-localization of these two peptides in cat lung. The co-localization procedure follows a standard immunocytochemical protocol except that the primary and labeled secondary antisera each contain a combination of two antisera allowing the simultaneous detection of two antigens in a single tissue section. Using fluorescence microscopy, VIP- and substance P-containing nerve fibers were co-localized in bronchial smooth muscle, in the walls of pulmonary and bronchial arteries, and around submucosal glands. VIP and substance P were also co-localized in nerve cell bodies that comprised the intrinsic airway ganglia. Substance P-containing nerve fibers were observed within the bronchial epithelium, but VIP was not present at this location. The co-localization of VIP and substance P in the same nerve fibers suggests that airway and pulmonary vascular function may be partially regulated by the simultaneous or sequential release of VIP and substance P from the same nerve fibers. The results also suggest that, in addition to extrinsic nerve fibers that contain substance P, the airways of cats are suplied by substance P-containing nerve fibers that originate from intrinsic nerve cell bodies.

Co-localization of vasoactive intestinal peptide (VIP) and enkephalins in chromaffin cells of the adrenal gland of amphibia. Stimulation of corticosteroid production by VIP

Recent studies have shown that biologically active peptides and monoaminergic neurotransmitters coexist in certain neuronal cell populations. Using the immunofluorescence technique, we have examined the localization of enkephalins, vasoactive intestinal peptide (VIP) and tyrosine hydroxylase in the adrenal gland of the frog Rana ridibunda . Most chromaffin cells which stained for tyrosine hydroxylase contained VIP-like immunoreactivity, whereas methionine- (Met-) and leucine- (Leu-) enkephalin-like immunoreactivity was detected in about 40% of the cells revealed by the anti-tyrosine hydroxylase serum. No VIP- or enkephalin-like immunoreactive nerve fibres were observed. Since in the frog, the chromaffin cells are in close contact with the adrenocortical (interrenal) tissue, a possible action of VIP and opiates on corticosteroidogenesis has been investigated. At doses 10 −6 and 10 −5M, 20-min infusions of synthetic porcine or chicken VIP elicited a significant increase in corticosterone and aldosterone production by perifused frog adrenals, in a dose-dependent manner. As compared to ACTH, VIP was several orders of magnitude less effective in stimulating corticosteroid production. Morphine, Met- and Leu-enkephalins (10 −5M) had no effect on spontaneous secretion of corticosteroids. In addition, Met- and Leu-enkephalins (10 −5M) did not alter the production of corticosterone induced by ACTH. These results suggest that VIP contained in the chromaffin cells of the frog adrenal gland may exert a local action in stimulating corticosteroid production by the interrenal tissue.