Biomedical subjects

W L Neuhuber

Publications and source records attributed to W L Neuhuber.

At least 37 records · Page 2Linked to original sources

PubMed2000

Calcium-dependent inactivation of neuronal calcium channel currents is independent of calcineurin.

Dephosphorylation by the Ca2+/calmodulin-dependent phosphatase calcineurin has been suggested as an important mechanism of Ca2+-dependent inactivation of voltage-gated Ca2+ channels. We have tested whether calcineurin plays a role in the inactivation process of two types of high-voltage-activated Ca2+ channels (L and N type) widely expressed in the central nervous system, using the immunosuppressive drug FK506 (tacrolimus), which inhibits calcineurin after binding to intracellular FK506 binding proteins. Inactivation of L- and N-type Ca2+ channels was studied in a rat pituitary tumor cell line (GH3) and chicken dorsal root ganglion neurons, respectively. With the use of antisera directed against the calcineurin subunit B and the 12,000 mol. wt binding protein, we show that both proteins are present in the cytoplasm of GH3 cells and chicken dorsal root ganglion neurons. Ionic currents through voltage-gated Ca2+ channels were investigated in the perforated-patch and whole-cell configurations of the patch-clamp technique. The inactivation of L- as well as N-type Ca2+ currents could be well fitted with a bi-exponential function. Inactivation was largely reduced when Ba2+ substituted for extracellular Ca2+ or when the Ca2+ chelator EGTA was present intracellularly, indicating that both types of Ca2+ currents exhibited Ca2+-dependent inactivation. Extracellular (perforated-patch configuration) or intracellular (whole-cell configuration) application of FK506 to inactivate calcineurin had no effect on the amplitude and time-course of Ca2+ channel current inactivation of either L- or N-type Ca2+ channels. In addition, we found that recovery from inactivation and rundown of N-type Ca2+ channel currents were not affected by FK506. Our results provide direct evidence that the calcium-dependent enzyme calcineurin is not involved in the inactivation process of the two Ca2+ channel types which are important for neuronal functioning, such as gene expression and transmitter release.

Animals↗

PubMed2000

Endomorphin-1 and -2, endogenous ligands for the mu-opioid receptor, inhibit striated and smooth muscle contraction in the rat oesophagus.

Recently, morphological evidence for an interaction of autonomic nerve fibres and extrinsic motor innervation of the rat oesophagus has emerged. The aim of the present study was to investigate the possible influence of endogenous and exogenous opioids on rat oesophageal smooth and striated muscle function in vitro. The entire oesophagus (excluding the lower oesophageal sphincter) with both Nervi (Nn) vagi, including the Nn recurrentes, was dissected and placed in an organ bath (100 mL, 37 degrees) with oxygenated Krebs-Ringer buffer. Contractile activity was measured in a longitudinal direction with a force transducer. Both Nn vagi were placed on a bipolar platinum electrode 2 cm distant from the oesophagus. Vagal stimulation (VS), applied for 1 s (40 V, 0.5 ms, 20 Hz) resulted in a biphasic contractile response that was completely blocked by 10(-6) M tetrodotoxin. The first part consisted of a tetanic striated muscle contraction, as it was abolished by tubocurarine (10(-5) M, n=5) but unaffected by atropine (10(-6) M, n=3) or hexamethonium (10(-4) M, n=4). In contrast, the second part was completely inhibited by hexamethonium (10(-4) M) and atropine (10(-6)M), whereas tubocurarine (10(-5) M) showed no influence, indicating a stimulation of preganglionic nerve fibres supplying oesophageal smooth muscle (muscularis mucosae) via relays in myenteric ganglia. In order to characterize opioid influence on the oesophageal striated and smooth muscle contractility, the following experiments were carried out. 10(-6) M endomorphin-1 and -2, endogenous mu-opioid-receptor agonists, reduced the contractile response of the striated (EM-2, -25.1+/-5.3%; n=16), and the smooth muscle (EM-2, -81.9+/-3.3%; n=11). Both effects were reversible by the opioid receptor antagonist naloxone (10(-6) M) and therefore, mediated via opioid receptors. Neither SNC-80, an agonist on the delta-opioid-receptor, U-69593, an agonist on the kappa-opioid-receptor, nor nociceptin, an agonist at the ORL1 (opioid receptor-like) receptor, had a significant effect on the striated muscle contraction. In contrast to SNC-80, U-69593 and nociceptin inhibited smooth muscle contraction but this relaxation could not be antagonized by naloxone. None of the opioid receptor antagonists used had an effect on basal tonus or muscle contraction following VS. Our data provide evidence for an autonomic modulation of vagal motor innervation of the striated and smooth oesophageal muscle. Endomorphin-1 and -2, both selective mu-opioid receptor agonists, cause an inhibition of striated and smooth muscle response which is reversible by naloxone, an opioid receptor antagonist. The location of the mu-opioid receptor still has to be established.

Animals↗

PubMed1999

Requirement of peptidergic sensory innervation for disease activity in murine models of immune hepatitis and protection by beta-adrenergic stimulation.

To investigate the interaction between the peripheral nervous and the immune system in vivo, we used two mouse models of T cell and TNF-alpha dependent liver injury inducible by either concanavalin A or a combination of D-galactosamine and staphylococcal enterotoxin B. Mice depleted of peptidergic sensory nerve fibres by capsaicin were protected from liver injury. Moreover, TNF-alpha production was significantly reduced. Examination of the effect of catecholamines on liver injury showed that the beta2-adrenergic agonist salbutamol prevented, whereas chemical sympathectomy by 6-hydroxydopamine, deteriorated the disease. Hence, strategies reducing the activity of peptidergic sensory nerve fibres or stimulating beta2-adrenoreceptors, may be of benefit in immune-mediated liver disease.

Adrenergic beta-Agonists↗

PubMed1998

Vagal and spinal afferent innervation of the rat esophagus: a combined retrograde tracing and immunocytochemical study with special emphasis on calcium-binding proteins.

Vagal afferent neurons contain a variety of neurochemical markers and neuroactive substances, most of which are present also in dorsal root ganglion cells. To test for the suitability of the calcium-binding protein calretinin as a specific marker for vagal afferent fibers in the periphery, immunocytochemistry for this protein was combined with retrograde tracing. Nerve fibers in the rat esophagus, as well as vagal and spinal sensory neurons innervating the esophagus, were investigated for co-localization of calretinin with calbindin, calcitonin gene-related peptide, and NADPH diaphorase. The results indicated that calretinin immunocytochemistry demonstrates neuronal structures known as vagal afferent from other studies, in particular intraganglionic laminar endings. A few enteric neurons whose distribution was unrelated to intraganglionic laminar endings also stained for calretinin. Strikingly, calretinin immunoreactivity was absent from spinal afferent neurons innervating the rat esophagus. In intraganglionic laminar endings and nodose ganglion cells calretinin was highly co-localized with calbindin but not with calcitonin gene-related peptide. On the other hand, calbindin was also found in spinal afferents to the esophagus where it was co-localized with calcitonin gene-related peptide. Vagal afferent neurons innervating the esophagus were never positive for NADPH diaphorase. Thus, calretinin appears to be a more specific marker for vagal afferent structures in the esophagus than calbindin, which is expressed by both vagal and spinal sensory neurons. Calretinin immunocytochemistry may be utilized as a valuable tool for investigations of subpopulations of vagal afferents in certain viscera.

Animals↗

PubMed1998

Vagal efferent and afferent innervation of the rat esophagus as demonstrated by anterograde DiI and DiA tracing: focus on myenteric ganglia.

Anterograde tracing with the carbocyanine tracer DiI and the aminostyrol derivative DiA was used to selectively label fibers from the nucleus ambiguus, dorsal motor nucleus and nodose ganglion, respectively, terminating in the rat esophagus, and to compare them with the innervation of the gastric fundus in the same animals. Ambiguus neurons terminated on motor endplates distributed mainly to the ipsilateral half of the esophagus. There was no evidence of preganglionic innervation of myenteric ganglia from ambiguus neurons. Neurons of the dorsal motor nucleus supplied sparse fibers to only about 10% of enteric ganglia in the esophagus while they innervated up to 100% of myenteric ganglia in the stomach. Neurons of the nodose ganglion terminated profusely on more than 90% of myenteric ganglia of the esophagus and on about 50% of ganglia in the stomach. Afferent vagal fibers were also frequently found in smooth muscle layers starting at the esophago-gastric junction. In contrast, they were extremely rare in the striated muscle part of the esophagus. These morphological data suggest a minor influence of neurons of the dorsal motor nucleus and a prominent influence of vagal afferent terminals onto myenteric neurons in the rat esophagus.

Animals↗

PubMed1998

[Characteristics of the innervation of the head and neck].

Innervation of the head and neck differs from other regions of the body in certain respects. In particular, besides the external cuneate nucleus, thick-calibre neck muscle afferents project directly, to the vestibular nuclear complex. This projection is most prominent in segments C2 and 3 and is sparse or absent in more caudal segments. Thus, proprioceptive neck muscle afferents gain direct access to vestibulospinal, vestibulooculomotor and other secondary or even higher order vestibular neurons that receive labyrinthine input. Proprioceptive input via indirect spinovestibular pathways is also most prominent from C2 and 3 compared to more caudal levels. Likewise, thin calibre, mainly nociceptive afferents from cervical segments are channelled via the parabrachial nuclei in the rostral pons to limbic structures different from the targets of thoracolumbar afferents. It is tempting to consider these neuroantomical peculiarities relevant for the pathogenesis of the puzzling symptoms after whiplash injury.

Brain Stem↗

PubMed1998

Close anatomical relationships between nerve fibers and MHC class II-expressing dendritic cells in the rat liver and extrahepatic bile duct.

The anatomical relationships between immunocytochemically identified nerve fibers and MHC class II-expressing antigen presenting dendritic cells were investigated in the rat hepatobiliary system using immunocytochemistry, confocal laser scanning, and electron microscopy. Close proximity of nerve fiber varicosities immunostained for PGP 9.5 and MHC class II-expressing dendritic cells was frequently observed in the wall of extrahepatic bile ducts, in Glisson's area, around central and hepatic veins, and in the liver capsule. Contacts between nerve fibers staining for substance P, calcitonin gene-related peptide, calretinin, and vasoactive intestinal polypeptide and dendritic cells were more often observed around extrahepatic bile ducts than in Glisson's area. Nerve fibers immunostaining for tyrosine hydroxylase and neuropeptide Y were numerous both in the wall of extrahepatic bile ducts and in Glisson's area and frequently contacted dendritic cells there. At the ultrastructural level, close membrane contacts between bare axolemmal areas of unmyelinated nerve fibers and processes of MHC class II-expressing cells were observed. These results demonstrate close anatomical relationships of nerve fibers from various sources with antigen presenting dendritic cells in the visceral domain and suggest modulation of antigen presentation by the autonomic nervous system.

Animals↗

PubMed1998

Nonvagal origin of galanin-containing nerve terminals innervating striated muscle fibers of the rat esophagus.

We investigated the origin of galanin-positive nerve fibers on motor endplates in rat esophagus using anterograde 1,1'-dioleyl-3,3,3', 3'-tetramethylindocarbocyanine methane sulfonate (DiI) tracing from the nucleus ambiguus combined with galanin immunocytochemistry and calcitonin gene-related peptide immunocytochemistry. To demonstrate spatial relationships of galanin-positive nerve fibers to vagal and enteric nerve fibers on motor endplates, we combined galanin immunocytochemistry with calcitonin gene-related peptide immunostaining for labeling of vagal terminals, and vasoactive intestinal peptide immunoreactivity and NADPH-diaphorase histochemistry for demonstration of enteric nerve fibers. Within fine varicose nerve fibers, galanin was colocalized with vasoactive intestinal peptide and NADPH-diaphorase to a high degree and turned out to be completely separated from calcitonin gene-related peptide-positive or anterogradely DiI-labeled vagal motor terminals. These results indicate that the enteric nervous system is the most important and possibly the only source of galanin-positive nerve terminals on motor endplates in rat esophagus. Galanin may be, in addition to nitric oxide and vasoactive intestinal peptide, a mediator of the enteric coinnervation of striated muscle in this organ.

Animals↗

PubMed1998

Pulmonary intraepithelial vagal nodose afferent nerve terminals are confined to neuroepithelial bodies: an anterograde tracing and confocal microscopy study in adult rats.

Our present understanding of the morphology of neuroepithelial bodies (NEBs) in mammalian lungs is comprehensive. Several hypotheses have been put forward regarding their function but none has been proven conclusively. Microscopic data on the innervation that appears to affect the reaction of NEBs to stimuli have given rise to conflicting interpretations. The aim of this study has been to check the validity of the hypothesis that pulmonary NEBs receive an extensive vagal sensory innervation. The fluorescent neuronal tracer DiI was injected into the vagal sensory nodose ganglion and NEBs were visualized in toto by using immunocytochemistry and confocal microscopy on 100-micrometer-thick frozen sections of the lungs of adult rats. The most striking finding was the extensive intraepithelial terminal arborizations of DiI-labelled vagal afferents in intrapulmonary airways, apparently always co-appearing with calcitonin gene-related peptide (CGRP)-immunoreactive NEBs. Not all NEBs received a traced nerve fibre. Intrapulmonary CGRP-containing nerve fibres, including those innervating NEBs, always appeared to belong to a nerve fibre population different from the DiI-traced fibres and hence did not arise from the nodose ganglion. Therefore, at least some of the pulmonary NEBs in adult rats are supplied with sensory nerve fibres that originate from the vagal nodose ganglion and form beaded ramifications between the NEB cells, thus providing support for the hypothesis of a receptor function for NEBs.

Animals↗

PubMed1997

Capsaicin-resistant vagal afferent fibers in the rat gastrointestinal tract: anatomical identification and functional integrity.

The presence and distribution of vagal fibers and terminals throughout esophagus and gastrointestinal tract that could be anterogradely labeled by nodose ganglion tracer injections was quantitatively assessed in capsaicin- and vehicle-pretreated adult rats, in order to identify the capsaicin-resistant population. Up to 90% of the intraganglionic laminar endings (IGLEs), in the myenteric plexus of the esophagus, and 70-90% in the stomach, as well as 57% of the intramuscular endings or arrays (IMAs) in the fundic stomach survived the capsaicin treatment, while in the upper small intestine only few and in the lower small intestine, the cecum and colon, virtually no IGLEs survived capsaicin treatment. Intramucosal terminals were not assessed. Furthermore, gastric balloon distension-induced c-Fos expression in the dorsal vagal complex was not significantly decreased in capsaicin-treated rats. It is concluded that among primary vagal afferents there is a capsaicin-resistant population that primarily innervates the esophagus and upper gastrointestinal tract, and a capsaicin-sensitive population that innervates mainly the lower tract. At least vagal gastric tension-sensitive afferents also seems to be functionally intact in that they may be capable of synaptically activating second-order neurons in the brainstem.

Animals↗

PubMed1997

Distribution and structure of vagal afferent intraganglionic laminar endings (IGLEs) in the rat gastrointestinal tract.

Intraganglionic laminar endings (IGLEs) are special terminal structures of vagal afferent fibers and have been demonstrated in the myenteric plexus of esophagus and stomach. In order to quantitatively map their presence and distribution over the entire gastrointestinal tract, including the small and large intestines, vagal afferents were anterogradely labeled in vivo by microinjections of the fluorescent carbocyanine dye DiI into the left or right nodose ganglion of adult male rats. In the most successfully labeled cases the highest density of IGLEs was found in the stomach, with about half to one-third of the myenteric ganglia receiving at least one IGLE. The proportion of myenteric ganglia innervated by IGLEs decreased in the small intestine; however, because of its large surface area this gut segment was estimated to contain the highest total number of IGLEs. Both the cecum and colon also contained significant numbers of IGLEs. In the stomach, this vagal afferent innervation by IGLEs was more or less lateralized, with less than 20% of labeled IGLEs found on the contralateral side with respect to the injection. The left/ventral vagus contributed a larger proportion of IGLEs to the proximal duodenum, while the right/dorsal vagus contributed a larger proportion of IGLEs to the distal duodenum and jejunum. Laser scanning confocal microscopy on select specimens revealed further structural details. The parent axon typically formed two or more branches that flanked the ganglia laterally, and in turn produced numerous highly arborizing laminar terminal branches that covered one or both flat sides of the ganglion in a dome-like fashion. The similar distribution patterns and structural details suggest a uniform function for the IGLEs throughout the gastrointestinal tract, but there is as yet no clear proof for any of the hypothesized roles as specialized mechanosensors or local effector terminals.

Animals↗

PubMed1997

Spatial relationships of enteric nerve fibers to vagal motor terminals and the sarcolemma in motor endplates of the rat esophagus: a confocal laser scanning and electron-microscopic study.

Enteric co-innervation of motor endplates in the rat esophagus was studied with confocal laser scanning and electron microscopy. Enteric fibers were demonstrated with immunocytochemistry for nitric oxide synthase, vasoactive intestinal peptide or NADPH-diaphorase histochemistry. Vagal motor terminals were identified with calcitonin gene-related peptide (CGRP) immunocytochemistry. Teloglia was stained with immuno- cytochemistry for S100, and TRITC-tagged alpha-bungarotoxin was used to delineate endplate areas in immmunofluorescence preparations. Both confocal imaging and electron microscopy revealed intimate relationships between enteric and vagal terminals on the one hand, and enteric terminals and the sarcolemma on the other. In addition, electron microscopy could point out direct apposition of a significant proportion of enteric varicosities to vagal motor terminals without intervening teloglial processes. These morphological data are compatible with pre- and postsynaptic modulatory effects of enteric neurons on vagal neuromuscular transmission in striated esophageal muscle.

Animals↗

PubMed1997

Comparison of preoperative innervation pattern and postreconstructive urodynamics in the exstrophy-epispadias complex.

A primary neurogenic component is often being postulated to be responsible for unfavourable postoperative results of bladder growth and continence in the exstrophy-epispadias complex. On the other hand, we have seen favourable clinical situations and urodynamic follow-up after primary reconstruction employing the 'Erlangen technique' without evidence of primary dysinnervation. Since there are only few data available on this issue, we decided to apply immunocytochemistry and histochemistry for neuronal markers as a further step to elucidate this problem. Transmural biopsies were obtained during reconstructive surgery from the bladder dome and trigone of 22 children between September 1994 and June 1995. Indirect immunocytochemistry for vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), substance P (SP) calcitonin gene-related product (CGRP) and protein gene product (PGP) 9.5, a universal marker for neuronal tissue and histochemistry for nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd), was performed on 14-micron cryostat sections. During the same period of time, control biopsies from 6 healthy bladders of an age-compatible group were subjected to the same examination. In addition, 19 patients were examined urodynamically after reconstruction in order to compare postoperative bladder function with the preexisting innervation pattern. No evidence of dysinnervation was found either morphologically or urodynamically in cases of isolated epispadias and classical exstrophy. Cases of exstrophies after failed reconstruction had muscular innervation deficiencies but increased sub and intraepithelial innervation. This group, according to morphological changes, also demonstrated bladder wall instability, decreased bladder compliance and absent detrusor contractions during micturition. All cloacal exstrophies had an extremely uneven innervation pattern with noticeable calibre differences of nerve fibres and bundles with simultaneously increased innervation density. Functionally these bladders were marked by small capacity and decreased compliance and absent detrusor function. All exstrophies in conjunction with an anal atresia or with a caudal regression syndrome (so-called 'transition forms') had a nearly universal pathological innervation pattern, compatible with cloacal exstrophies and had equally unfavourable functional findings. Cloacal exstrophies and 'transition forms' seemed to have primarily a completely different pattern of innervation when compared to normal bladders. Prognosis of bladder function in these children remains unclear.

Adolescent↗

PubMed1996

Nitrergic and VIPergic neurons in the choroid and ciliary ganglion of the duck Anis carina.

Immunohistochemistry for neuronal nitric oxide synthase (nNOS) and vasoactive intestinal peptide (VIP), and NADPH diaphorase histochemistry, were applied to investigate neurons in the choroid and the ciliary ganglion of the muscovy duck Anis carina. Up to 1000 neurons in the choroid stained for NADPH diaphorase and showed virtually complete colocalization for nNOS immunoreactivity. Almost all of them co-stained for VIP, while about 90% of VIP immunoreactive cell bodies showed colocalization for nNOS. Two-thirds of the neurons were located, mostly singly, at nodes of a wide-meshed nerve plexus in the suprachoroid and were only rarely grouped in ganglia of up to 3 neurons. Numerous varicose nNOS/NADPH-diaphorase-positive nerve fibers were seen around large arterial blood vessels. These fibers derived mainly from paravascular cell bodies that represented about one-third of all choroidal neurons and also displayed costaining for nitrergic markers and VIP. Colocalization of nNOS/NADPH-d and VIP could be demonstrated in most of the perivascular fibers, while slightly more VIP-positive axons in the suprachoroid plexus did not costain for nNOS/NADPH-d. Small-caliber blood vessels and those localized in the choriocapillaris were not endowed with VIP/nNOS/NADPH-diaphorase-positive fibers. A few reactive neuronal cell bodies were also found in ciliary nerves, while most ciliary axons were unstained. In the ciliary ganglion a small subpopulation of neurons showed VIP/nNOS/NADPH-diaphorase colocalization. There were also nNOS/NADPH-d-positive cap-like terminals on ciliary ganglion cells. The presence of VIP/nNOS/NADPH-diaphorase positive neurons and nerve fibers in both the choroid and ciliary ganglion, and in the choroidal perivascular plexus, indicates peripheral nitrergic and VIPergic control of blood flow in the choroid of the duck.

Animals↗

PubMed1995

Vagal sensors in the rat duodenal mucosa: distribution and structure as revealed by in vivo DiI-tracing.

Results from functional studies point to the importance of chemoreceptive endings in the duodenum innervated by vagal afferents in the regulation of gastrointestinal functions such as gastric emptying and acid secretion, as well as in the process of satiation. In order to visualize the vagal sensory innervation of this gut segment, vagal afferents were selectively labeled in vivo by injecting the lipophilic carbocyanine dye DiI into either the left or the right nodose ganglion of young adult rats. Thick cryostat sections or whole-mounted peels of muscularis externa or submucosa of formalin-fixed tissue were analyzed with conventional and/or confocal microscopy. In the mucosa, many DiI-labeled vagal afferent fibers were found with terminal arborizations mainly between the crypts and the villous lamina propria. In both areas, vagal terminal branches came in close contact with the basal lamina, but did not appear to penetrate it so as to make direct contact with epithelial cells. Labeled vagal afferent fibers in the villous and cryptic lamina propria were found to be in intimate anatomical contact with fibrocyte-like cells that may belong to the class of interstitial cells of Cajal, and with small granular cells that might be granulocytes or histiocytes. Although our analysis was not quantitative, and considering that labeling was unilateral and not complete, it appears that the overall density of vagal afferent mucosal innervation was variable; many villi showed no evidence for innervation while other areas had quite dense networks of arborizing terminal fibers in several neighboring villi. Analysis of separate whole-mounted muscularis externa and submucosa peels revealed the presence of large bundles of labeled afferent fibers running within the myenteric plexus along the mesenteric attachment primarily in an aboral direction, with individual fibers turning towards the antimesenteric pole, and either penetrating into the submucosa or forming the characteristic intraganglionic laminar endings (IGLEs). Although the possibility of individual fibers issuing collaterals to myenteric IGLEs and at the same time to mucosal terminals was not demonstrated, it cannot be ruled out. These anatomical findings are discussed in the context of absorptive mechanisms for the different macronutrients and the implication of enteroendocrine cells such as CCK-containing cells that may function as intestinal "taste cells".

Animals↗

PubMed1995

Vagal afferent innervation of rat abdominal paraganglia as revealed by anterograde DiI-tracing and confocal microscopy.

Abdominal vagal afferent fibers were selectively labeled by injecting the fluorescent carbocyanine dye DiI into the left nodose ganglion of rats. Almost all paraganglia that were distributed along the five major abdominal vagal branches and their subbranches were found to be innervated by labeled vagal afferents. Laser scanning confocal microscopy with its single optical sectioning and three-dimensional reconstruction capabilities were used to analyze this innervation in more detail for paraganglia near the vagal hepatic branch and liver hilus. Furthermore, in double-labeling studies, it was demonstrated that a large percentage of the vagally innervated glomus cells were capable of catecholamine synthesis on the basis of their positive staining for tyrosine hydroxylase antibody. These findings support the concept of a chemoreceptive function for the abdominal paraganglia.

Animals↗

PubMed1994

Innervation of laryngeal nerve paraganglia: an anterograde tracing and immunohistochemical study in the rat.

Carotid body-like organs, paraganglia, frequently occur in the superior and recurrent laryngeal nerves. The paraganglia are supplied with a rich innervation of unknown origin. In the present study, the origin of the innervation of the paraganglia of the rat was studied with two different techniques. One approach was anterograde tracing of wheat-germ agglutinin-horseradish peroxidase after injection into the nodose and jugular ganglia of the vagus and the superior cervical ganglion. The other approach was immunohistochemical staining for neuropeptides after excision of the superior cervical ganglion, or vagotomy. Antisera against neuropeptide Y, vasoactive intestinal polypeptide, and calcitonin gene-related peptide were utilized. Both the tracing method and calcitonin gene-related peptide immunohistochemistry after vagotomy showed that the paraganglia receive sensory innervation from the vagal ganglia. No labeling was detected in the paraganglia after injection of wheat-germ agglutinin-horseradish peroxidase in the superior cervical ganglion. Excision of this ganglion did not lead to a decrease in the neuropeptide-Y innervation in the paraganglia, but most of this innervation in the surrounding blood vessels disappeared. The observations show that the superior cervical ganglion does not contribute to the innervation in the paraganglia and that the neuropeptide-Y innervation of the blood vessels originates from the superior cervical ganglion whereas that of the paraganglia has another origin, most likely local ganglionic cells. The results also suggest that the vasoactive intestinal polypeptide innervation in the paraganglia arises from local ganglionic cells. The two approaches complemented each other in mapping the afferent and efferent nerve supply of the paraganglia.

Animals↗

PubMed1994

Neuronal and endothelial nitric oxide synthase immunoreactivity and NADPH-diaphorase staining in rat and human pancreas: influence of fixation.

In this study, we wished to clarify the distribution and co-localization of nitric oxide synthase and NA-DPH-diaphorase (NADPH-d) in nerve cells, nerve fibres and parenchymal cells in exocrine and endocrine pancreas, and to assess the influence of fixation on the staining pattern obtained. For this purpose, we applied nitric oxide synthase immunocytochemistry and NADPH-d histochemistry to rat and human pancreas under different fixation conditions. Antibodies to neuronal and endothelial nitric oxide synthase were similarly applied. We found complete co-localization of neuronal nitric oxide synthase and NADPH-d in ganglion cells, and in nerve fibres around acini, excretory ducts, blood vessels and in islets of Langerhans of rat and human pancreas. Immunoreactivity for endothelial nitric oxide synthase was co-localized with NADPH-d in endothelial cells. However, in NADPH-d reactive islet and ductal epithelial cells we could detect neither brain nor endothelial nitric oxide synthase immunoreactivity with any fixation protocol applied. There were marked differences in NADPH-d staining of both neurons and parenchymal cells under different fixation conditions. These results indicate the existence of different types of NADPH-d, which are associated or not associated with nitric oxide synthase(s), and which are differently influenced by various fixation procedures in rat and human pancreas.

Acetone↗