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W Kummer

Publications and source records attributed to W Kummer.

At least 55 records · Page 3Linked to original sources
PubMed1996

Induction of tachykinin gene and peptide expression in guinea pig nodose primary afferent neurons by allergic airway inflammation.

Substance P (SP), neurokinin A (NKA), and calcitonin gene-related peptide (CGRP) have potent proinflammatory effects in the airways. They are released from sensory nerve endings originating in jugular and dorsal root ganglia. However, the major sensory supply to the airways originates from the nodose ganglion. In this study, we evaluated changes in neuropeptide biosynthesis in the sensory airway innervation of ovalbumin-sensitized and -challenged guinea pigs at the mRNA and peptide level. In the airways, a three- to fourfold increase of SP, NKA, and CGRP, was seen 24 h following allergen challenge. Whereas no evidence of local tachykinin biosynthesis was found 12 h after challenge, increased levels of preprotachykinin (PPT)-A mRNA (encoding SP and NKA) were found in nodose ganglia. Quantitative in situ hybridization indicated that this increase could be accounted for by de novo induction of PPT-A mRNA in nodose ganglion neurons. Quantitative immunohistochemistry showed that 24 h after challenge, the number of tachykinin-immunoreactive nodose ganglion neurons had increased by 25%. Their projection to the airways was shown. Changes in other sensory ganglia innervating the airways were not evident. These findings suggest that an induction of sensory neuropeptides in nodose ganglion neurons is crucially involved in the increase of airway hyperreactivity in the late response to allergen challenge.

Animals↗
PubMed1996

Anatomical and electrophysiological comparison of the sensory innervation of bronchial and tracheal parasympathetic ganglion neurons.

Anatomical and electrophysiological techniques were used to examine differences in the level of sensory nerve terminals localized in parasympathetic ganglia in guinea pig trachea and bronchus. We quantified substance-P-immunoreactive nerve terminal profiles within the ganglia and the amplitude of capsaicin-sensitive depolarization (slow excitatory postsynaptic potential or sEPSP) evoked by vagus (bronchial) or recurrent (tracheal) nerve-stimulation. Substance-P-immunoreactive axon profiles per intrinsic tracheal neuron were fewer in number than per bronchial ganglion neuron. The average amplitude and duration of the capsaicin-sensitive sEPSPs were similar in tracheal and bronchial ganglion neurons. Furthermore, capsaicin evoked a nearly equal depolarization of bronchial and tracheal ganglion neurons. The sEPSPs were reduced in both areas by a selective neurokinin-3 receptor antagonist. SR142801. These results demonstrate that although the number of sensory nerve fibers in tracheal ganglia are significantly less than those in the bronchus, this did not translate to an obvious physiological difference in sEPSP amplitude.

Animals↗
PubMed1996

Interganglionic segregation of distinct vagal afferent fibre phenotypes in guinea-pig airways.

1. The present study addressed the hypothesis that jugular and nodose vagal ganglia contain the somata of functionally and anatomically distinct airway afferent fibres. 2. Anatomical investigations were performed by injecting guinea-pig airways with the neuronal tracer Fast Blue. The animals were killed 7 days later, and the ganglia were removed and immunostained with antisera against substance P (SP) and neurofilament protein (NF). In the nodose ganglion, NF-immunoreactive neurones accounted for about 98% of the Fast Blue-labelled cells while in the jugular ganglion they accounted for approximately 48%. SP and NF immunoreactivity was never (n = 100) observed in the same cell suggesting that the antisera labelled distinct populations. 3. Electrophysiological investigations were performed using an in vitro guinea-pig tracheal and bronchial preparation with intact afferent vagal pathways, including nodose and jugular ganglia. Action potentials arriving from single airway afferent nerve endings were monitored extracellularly using a glass microelectrode positioned near neuronal cell bodies in either ganglion. 4. The nodose ganglion contained the somata of mainly fast-conducting tracheal A delta fibres whereas the jugular ganglion contained equal numbers of C fibre and A delta fibre tracheal afferent somata. The nodose A delta neurones adapted rapidly to mechanical stimulation, had relatively low mechanical thresholds, were not activated by capsaicin and adapted rapidly to a hyperosmotic stimulus. By contrast, jugular A delta and C fibres adapted slowly to mechanical stimulation, were often activated by capsaicin, had higher mechanical thresholds and displayed a slow adaptation to a hyperosmotic stimulus. 5. The anatomical, physiological and pharmacological data provide evidence to support the contention that the vagal ganglionic source of the fibre supplying the airways ultimately dictates its neurochemical and physiological phenotype.

Action Potentials↗
PubMed1996

Localization, regulation and functions of neurotransmitters and neuromodulators in cervical sympathetic ganglia.

Cervical sympathetic ganglia represent a suitable model for studying the establishment and plasticity of neurochemical organization in the nervous system since sympathetic postganglionic neurons: (1) express several neuromediators, i.e., short acting transmitters, neuropeptide modulators and radicals, in different combinations; (2) receive synaptic input from a limited number of morphologically and neurochemically well-defined neuron populations in the central and peripheral nervous systems (anterograde influence on phenotype); (3) can be classified morphologically and neurochemically by the target they innervate (retrograde influence on phenotype); (4) regenerate readily, making it possible to study changes in neuromediator content after axonal lesion and their possible influence on peripheral nerve regeneration; (5) can be maintained in vitro in order to investigate effects of soluble factors as well as of membrane bound molecules on neuromediator expression; and (6) are easily accessible. Acetylcholine and noradrenaline, as well as neuropeptides and the recently discovered radical, nitric oxide, are discussed with respect to their localization and possible functions in the mammalian superior cervical and cervicothoracic (stellate) paravertebral ganglia. Furthermore, mechanisms regulating transmitter synthesis in sympathetic neurons in vivo and in vitro, such as soluble factors, cell contact or electrical activity, are summarized, since modulation of transmitter synthesis, release and metabolism plays a key role in the neuronal response to environmental influences.

Acetylcholine↗
PubMed1996

Subunits of soluble guanylyl cyclase in rat and guinea-pig sensory ganglia.

Soluble guanylyl cyclase is a heterodimeric (alpha, beta) enzyme generating the second messenger, cGMP, upon activation by the gaseous messenger, nitric oxide. The occurrence and distribution of alpha 1-, alpha 2-, beta 1- and beta 2-subunits were investigated in trigeminal and dorsal root ganglia on the mRNA and the protein level. Reverse transcription PCR analysis demonstrated mRNA coding for alpha 1-, alpha 2-, and beta 1-subunits in guinea-pig trigeminal and dorsal root ganglia. In agreement with these data, immunoreactivity to the alpha 1-subunit was found in satellite and Schwann cells, while alpha 2-subunit immunoreactivity was localized to axons of large diameter. The distribution of the beta 1-subunit could not be studied on the protein level since the antiserum was ineffective in immunohistochemistry. However, previous studies and the RT-PCR data argue in favour of alpha 1/beta 1-and alpha 2/beta 1-heterodimerization and colocalization. In both species, beta 2-subunit immunoreactivity was confined to neuronal perikarya, primarily of large diameter. Although these results were obtained with two different antibodies directed against different epitopes, the corresponding mRNA could not be detected by RT-PCR analysis. The reason for this discrepancy remains unclear, at present, but could be explained by a variant beta 2- or highly homologous as yet unidentified beta-subunit. This study demonstrates the presence of soluble guanylyl cyclase in sensory ganglia with a differential, cell type-specific distribution of the individual subunits.

Amino Acid Sequence↗
PubMed1996

Nitric oxide synthase in vagal sensory and sympathetic neurons innervating the guinea-pig trachea.

Sympathetic (stellate and superior cervical ganglion) and sensory vagal (nodose and jugular ganglion) neurons innervating the guinea-pig trachea were labelled using a retrograde neuronal tracer (Fast Blue) and tested for immunoreactivity to nitric oxide synthase (NOS) and either tyrosine hydroxylase (TH; sympathetic ganglia) or substance P (SP; vagal afferent neurons). Approx. 3% of the sympathetic neurons innervating the trachea were NOS-positive. These neurons belonged to the non-catecholaminergic phenotype. Amongst the retrogradely labelled neurons in the vagal sensory ganglia, 5-10% of retrogradely labelled neurons in the nodose (inferior vagal) ganglion, and 10-20% of those in the jugular (superior vagal) ganglion were NOS-immunoreactive. All NOS-positive vagal afferent neurons labelled with retrograde tracer were negative for substance P. Accordingly, the results of these studies provide evidence that portions of the sympathetic and sensory innervation of the guinea-pig trachea is provided by NOS-immunoreactive neurons.

Animals↗
PubMed1996

Heme oxygenase-2 in primary afferent neurons of the guinea-pig.

Sensory ganglia (trigeminal, jugular, nodose, cervical and lumbar dorsal root ganglia) of the guinea-pig were investigated for the presence of a constitutive carbon monoxide-generating enzyme, heme oxygenase-2 (HO-2). A 36-kDa HO-2 immunoreactive protein was identified by Western blotting in protein extracts from dorsal root ganglia and localized by immunohistochemistry to all neuronal perikarya, including both substance P-positive and substance P-negative neurons, in all ganglia investigated. This ubiquitous distribution points to a general requirement for HO-2 in primary afferent neurons rather than to an association with a specific functionally defined subpopulation. Neither the axons of the sensory neurons nor their peripheral terminals in the skin and around visceral arteries were HO-2 immunoreactive. Explants of dorsal root ganglia with crushes placed on the dorsal roots showed accumulation of the neuropeptide, substance P, at the ganglionic side of the crush, but these axons were non-reactive to HO-2, indicating that there is no substantial transport of HO-2 towards the central ending of these sensory neurons. Collectively, the findings suggest that HO-2 exerts it major effects within the sensory ganglia themselves.

Animals↗
PubMed1996

beta 2-adrenoreceptor immunoreactivity in cardiac ganglia of the guinea pig.

Previous pharmacological studies in co-culture systems have indicated the presence of beta-adrenoreceptors on intrinsic cardiac neurons of the guinea pig (Horackova et al., 1993) but radioligand binding studies on tissue sections failed to provide a definite answer as to the presence of such receptors on cardiac neurons in situ, due to the iodine-binding properties of cardiac nerve bundles and ganglia (Molenaar et al., 1992). We therefore addressed this question by immunohistochemistry, using antisera raised against synthetic peptides of the beta 2-adrenoreceptor. For comparison, cholinergic and catecholaminergic neurons were identified immunohistochemically by means of antibodies against the enzymes involved in the synthesis of acetylcholine (choline acetyltransferase), and of catecholamines (tyrosine hydroxylase). Virtually all intrinsic cardiac neurons contained both beta 2-adrenoreceptor- and choline acetyltransferase-immunoreactivities. In addition, some nerve fibre bundles exhibited beta 2-adrenoreceptor-immunoreactivity. Several ganglia were innervated by tyrosine hydroxylase-immunoreactive axons, but the majority of ganglia did not receive tyrosine hydroxylase-immunoreactive nerve terminals, and additional intraganglionic sources of catecholamine synthesis could not be identified. Thus, the results are in favour of beta-adrenergic modulation of guinea pig cardiac ganglia by humorally and, partially, by locally released catecholamines.

Animals↗
PubMed1996

[Projections and fiber characteristics of sensory afferents of the anterior cruciate ligament in an animal experiment].

The sensory innervation of the rabbit anterior cruciate ligament was studied by retrograde tracing technique using wheat-germ-agglutinin-horseradish-peroxidase (WGA-HRP) and Fast Blue as neuronal tracers. Injection of the tracer into the ligament was followed by histo- and immunohistochemical investigation of labelled nerve cell bodies located in the dorsal root ganglia. In 4 animals we injected the tracer into the joint cavity to label general joint afferents. The segmental distribution of retrogradely labelled neurons following injection into the anterior cruciate ligament (L6, L7, S1) is significantly different from the distribution pattern after injection into the knee joint (L4-S2). Retrogradely labelled nerve cells innervating the anterior cruciate ligament were further investigated using immunohistochemical and morphometric analysis. The sensory innervation of the anterior cruciate ligament is therefore comprised of at least 2 different qualities of sensory afferent nerves: 1. Small neurones immunoreactive to the inflammatory peptide substance P most likely transmitting nociceptive information centrally (44%). 2. Large, presumably fast conducting A-fibre-afferents characterized by neurofilament proteins transmitting proprioceptive information from corpuscular mechanoreceptors (43%). The results of this study put further weight to the importance of the sensory role of the anterior cruciate ligament using neuroanatomical and immunohistochemical techniques.

Afferent Pathways↗
PubMed1996

Reconstruction of the anterior cruciate ligament with a cyropreserved ACL allograft. A microangiographic and immunohistochemical study in rabbits.

The ACL in the rabbit is innervated by three types of nerve fibres. These subserve vasoconstriction, nociceptive and proprioceptive purposes. The aim of this paper was to investigate the revascularisation and reinnervation of cyropreserved ACL allografts in 22 New Zealand white rabbits. Cyropreserved grafts were used as they may excite less host immune response. Both microangiographic and immunohistochemical methods were used. We found that cryopreserved allografts exhibited little immune response, revascularisation was considerable by the 24th postoperative week and reinnervation was essentially complete by then. No mechanoreceptors were found in ACL allografts. In rabbits, the anatomical basis for the participation of ACL allografts in sensorimotor reflexes is not given before the twelfth week after transplantation.

Animals↗
PubMed1995

Guinea-pig sympathetic postganglionic neurones contain haem oxygenase-2.

HAEM oxygenase-2 (HO-2) is the neuronal isoform of the only known mammalian enzyme generating the new transmitter candidate, carbon monoxide. Its distribution was investigated in the sympathetic nervous system. A 36 kDa HO-2 immunoreactive protein was identified in the particulate fraction of stellate ganglion and cerebellum in Western blots. Immunohistochemically, all noradrenergic and non-noradrenergic postganglionic neurones were HO-2 immunoreactive in prevertebral ganglia and cervical, thoracic, and lumbar sympathetic chain ganglia. Neither postganglionic nerve branches nor noradrenergic perivascular terminals were HO-2 immunoreactive under control conditions. However, accumulation of HO-2 immunoreactivity was found in noradrenergic axons in explanted sciatic nerves in which axonal transport was interrupted by crushing. We conclude that HO-2 is ubiquitous in perikarya of postganglionic sympathetic neurones, is subjected to axonal transport but does not accumulate at sympathetic neuroeffector junctions. This distribution favours a general role of HO-2 in sympathetic neuronal metabolism rather than a specific association with transmission at autonomic neuroeffector junctions.

Animals↗
PubMed1995

Chemical codes of sensory neurons innervating the guinea-pig adrenal gland.

Retrograde neuronal tracing in combination with double-labelling immunofluorescence was applied to distinguish the chemical coding of guinea-pig primary sensory neurons projecting to the adrenal medulla and cortex. Seven subpopulations of retrogradely traced neurons were identified in thoracic spinal ganglia T1-L1. Five subpopulations contained immunolabelling either for calcitonin gene-related peptide (CGRP) alone (I), or for CGRP, together with substance P (II), substance P/dynorphin (III), substance P/cholecystokinin (IV), and substance P/nitric oxide synthase (V), respectively. Two additional subpopulations of retrogradely traced neurons were distinct from these groups: neurofilament-immunoreactive neurons (VI), and cell bodies that were nonreactive to either of the antisera applied (VII). Nerve fibers in the adrenal medulla and cortex were equipped with the mediator combinations I, II, IV and VI. An additional meshwork of fibres solely labelled for nitric oxide synthase was visible in the medulla. Medullary as well as cortical fibres along endocrine tissue apparently lacked the chemical code V, while in the external cortex some fibre exhibited code III. Some intramedullary neuronal cell bodies revealed immunostaining for nitric oxide synthase, CGRP or substance P, providing an additional intrinsic adrenal innervation. Perikarya, immunolabelled for nitric oxide synthase, however, were too few to match with the large number of intramedullary nitric oxide synthase-immunoreactive fibres. A non-sensory participation is also supposed for the particularly dense intramedullary network of solely neurofilament-immunoreactive nerve fibres. The findings give evidence for a differential sensory innervation of the guinea-pig adrenal cortex and medulla. Specific sensory neuron subpopulations suggest that nervous control of adrenal functions is more complex than hitherto believed.

Adrenal Cortex↗
PubMed1995

Nitric oxide synthase in guinea pig sympathetic ganglia: correlation with tyrosine hydroxylase and neuropeptides.

Nitric oxide synthase (NOS) has previously been reported in a small population of postganglionic sympathetic neurons in the guinea pig. The present study of paravertebral ganglia and the inferior mesenteric ganglion aimed to classify these neurons according to their content of neuropeptides (calcitonin gene-related peptide, neuropeptide Y, vasoactive intestinal peptide) and the rate-limiting enzyme of catecholamine synthesis, tyrosine hydroxylase, by means of immunohistochemical and histochemical double-labelling techniques. NOS-containing neurons belonged to the non-catecholaminergic population of postganglionic neurons, and partial co-existence was found with neuropeptide Y and vasoactive intestinal peptide immunoreactivities but not with calcitonin gene-related peptide. However, most of the NOS-containing neurons contained none of the neuropeptides, thus representing a hitherto unrecognized population of postganglionic neurons. The findings show that NOS is localized to small but neurochemically highly specific populations of postganglionic neurons, which most likely reflects an association with target- and function-specific pathways.

Animals↗
PubMed1995

Regulatory peptides in the human soft palate.

The distributions of vasoactive intestinal polypeptide, peptide, histidine methionine, helospectin, neuropeptide Y and its C-flanking peptide, substance P and calcitonin gene-related peptide were studied in the human soft palate using immunocytochemical techniques. Peptide-containing nerve fibers were found to form a dense network around glandular acini, excretory ducts and blood vessels, as well as beneath and within the epithelium. Chromogranin A, bombesin-flanking peptide and calcitonin gene-related peptide immunoreactivities were detected in endocrine-like cells located in excretory ducts.

Calcitonin Gene-Related Peptide↗
PubMed1995

Immunohistochemical demonstration of four subunits of neutrophil NAD(P)H oxidase in type I cells of carotid body.

We demonstrate, by means of immunohistochemistry, that type I cells of human, guinea pig, and rat carotid bodies react with antisera raised against the subunits p22phox, gp91phox, p47phox, and p67phox of the NAD(P)H oxidase isolated from human neutrophil granulocytes. The findings support previous photometric studies that indicate that carotid body type I cells possess a putative oxygen sensor protein that is similar to the neutrophil NAD(P)H oxidase and consists of a hydrogen peroxide generating low-potential cytochrome b558 with cofactors regulating the electron transfer to oxygen.

Amino Acid Sequence↗
PubMed1995

Preprotachykinin-A gene expression occurs transiently in the developing rat endocrine pancreas and can be regulated in RINm5F cells.

We have reported previously that the rat insulinoma cell lines, RINm5F and RINr1046-38, express the preprotachykinin(PPT)-A gene, which encodes the tachykinin peptides, substance P and neurokinin A. Because endocrine cells of the adult rat pancreas do not appear to express PPT-A, we investigated whether the gene is expressed by rat pancreatic endocrine cells during development. We used immunohistochemistry, employing different substance P and neurokinin A antibodies, to show that many endocrine cells of the fetal and neonatal rat pancreas synthesise these products of PPT-A gene expression. Colabeling experiments revealed that a significant number of both insulin-containing and non-insulin-containing cells express tachykinins. After postnatal day 20, the number of tachykinin-immunoreactive pancreatic islet cells declines and, as already reported, none were detected in the adult rat pancreas. The transient expression of PPT-A by the developing endocrine pancreas is a novel finding. Substance P and neurokinin A are known to have trophic actions and may serve as growth factors during pancreatic islet development. PPT-A gene expression by RINm5F and RINr1046-38 cells is further evidence that these cells resemble developing pancreatic endocrine cells. They are potentially valuable as unique models for studying the regulation of tachykinin biosynthesis. We provide evidence in this study, using quantitative PPT-A messenger RNA analysis, that PPT-A expression in RINm5F cells may be up-regulated by activation of protein kinase C, down-regulated by activation of glucocorticoid receptors, and is not significantly affected by changes in intracellular cAMP levels.

Animals↗