Neurotransmitter localization in the neuroepithelial cells and unipolar neurons of the respiratory tract in the bichir, Polypterus bichir bichir G. ST-HIL (original) (raw)
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Innervation and Neurotransmitter Localization in the Lung of the Nile bichirPolypterus bichir bichir
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2007
Anatomical and functional studies of the autonomic innervation in the lung of dipnoan fishes and the bichirs are lacking. The present immunohistochemical studies demonstrated the presence of nerve fibers in the muscle layers of the lung of the bichir, Polypterus bichir bichir, and identified the immunoreactive elements of this innervation. Tyrosine hydroxylase, acetylcholinesterase, and peptide immunoreactivity was detected in the intramural nerve fibers. Extensive innervation was present in the submucosa where adenylatecyclase/activating polypeptide 38, substance P, P2X2, and 5-hydroxytryptamine (5-HT)–immunoreactive nerve fibers mainly supplied blood vessels. A collection of monopolar neurons located in the submucosal and the muscular layers of the glottis expressed a variety of various transmitters. These neurons may be homologous to ganglion cells in the branchial and pharyngeal rami of the vagus in fishes. Nerves containing 5-HT and P2X2 receptor immunoreactivity projected to the lung epithelium. Associated with neuroepithelial cells in mucociliated epithelium, were neuronal nitric oxide synthase–immunopositive axons. The physiological function of this innervation is not known. The present study shows that the pattern of autonomic innervation of the bichir lung may by similar in its elements to that in tetrapods. Anat Rec, 290:1166–1177, 2007. © 2007 Wiley-Liss, Inc.
Neurochemical features of the innervation of respiratory organs in some air‐breathing fishes
Italian Journal of Zoology, 2005
ABSTRACT A number of studies has been performed in recent years regarding the structure of the autonomic innervation of the gill and various organs of fishes, but only limited information exists on the role of the autonomic nervous system in air-breathing organs. The mechanisms for physiologically integrating gill and air-breathing organs are also not fully understood. The presence of neuropeptides and nNOS in gill autonomie nerves has been investigated in recent years by several Authors. Immunohistochemical localization of neuropeptides and nNOS in the autonomie nerves in the vasculatures and smooth muscle of air-breathing organs is reported for the first time. The function of NO in these tissues also remains to be elucidated especially, when the bulk of neurotransmission is attributable to cholinergic and adrenergic mechanisms. A challenge for future years is to understand the role of the autonomie nervous systems and the vasoactive substances in the in-series and in-parallel vascular connections between systemic gill and air-breathing organs.
Acta Histochemica, 2003
Gill and air sac of the indian catfish Heteropneustes fossilis harbour a nerve network comprising an innervated system of neuroepithelial endocrine cells; the latter cells are found especially in the gill. A series of antibodies was used for the immunohistochemical detection of neurotransmitters of the neural non-adrenergic, non-cholinergic (NANC) systems such as the sensory neuropeptides (enkephalins), the inhibitory neuropeptide VIP and neuronal nitric oxide synthase (nNOS) responsible for nitric oxide (NO) production which is an inhibitory NANC neurotransmitter. NADPH-diaphorase (NADPH-d) histochemistry was used as marker of nNOS although it is not a specific indicator of constitutively-expressed NOS in gill and air sac tissues. A tyrosine hydroxylase antibody was used to investigate adrenergic innervation. Nitrergic and VIP-positive sensory innervation was found to be shared by gill and air sac. Immunohistochemistry revealed the presence of enkephalins, VIP, NOS and NADPH-d in nerves associated with branchial and air sac vasculature, and in the neuroendocrine cell systems of the gill. Adrenergic nerve fibers were found in some parts of the air sac vasculature. The origin of the nerve fibers remains unclear despite previous findings showing the presence of both NADPH-d and nNOS in the sensory system of the glossopharyngeal and vagus nerves including the branchial structure. Scarce faintly stained nNOS-positive neurons were located in the gill but were never detected in the air sac. These findings lead to the conclusion that a postganglionic innervation of the airways is absent. Mucous goblet cells in the gill were found to express nNOS and those located in the non-respiratory interlamellar areas of the air sac were densely innervated by nNOS-positive and VIP-positive nerve fibers. Our immunohistochemical studies demonstrate that most arteries of the gill and air sac share a NANC (basically nitrergic) innervation which strongly suggests that they are homologous structures.
Neuropeptides and nitric oxide synthase in the gill and the air-breathing organs of fishes
Journal of Experimental Zoology Part A: Comparative Experimental Biology, 2006
Anatomical and histochemical studies have demonstrated that the bulk of autonomic neurotransmission in fish gill is attributed to cholinergic and adrenergic mechanisms (Nilsson. In many tissues, blockade of adrenergic and cholinergic transmission results in residual responses to nerve stimulation, which are termed NonAdrenergic, NonCholinergic (NANC). The discovery of nitric oxide (NO) has provided a basis for explaining many examples of NANC transmissions with accumulated physiological and pharmacological data indicating its function as a primary NANC transmitter.
Neurochemical pattern of the complex innervation of neuroepithelial bodies in mouse lungs
Histochemistry and Cell Biology, 2009
As best characterized for rats, it is clear that pulmonary neuroepithelial bodies (NEBs) are contacted by a plethora of nerve Wber populations, suggesting that they represent an extensive group of multifunctional intraepithelial airway receptors. Because of the importance of genetically modiWed mice for functional studies, and the current lack of data, the main aim of the present study was to achieve a detailed analysis of the origin and neurochemical properties of nerve terminals associated with NEBs in mouse lungs. Antibodies against known selective markers for sensory and motor nerve terminals in rat lungs were used on lungs from control and vagotomized mice of two diVerent strains, i.e., Swiss and C57-Bl6. NEB cells were visualized by antibodies against either the general neuroendocrine marker protein gene-product 9.5 (PGP9.5) or calcitonin gene-related peptide (CGRP). Thorough immunohistochemical examination of NEB cells showed that some of these NEB cells also exhibit calbindin D-28 k (CB) and vesicular acetylcholine transporter (VAChT) immunoreactivity (IR). Mouse pulmonary NEBs were found to receive intraepithelial nerve terminals of at least two diVerent populations of myelinated vagal aVerents: (1) Immunoreactive (ir) for vesicular glutamate transporters (VGLUTs) and CB; (2) expressing P2X 2 and P2X 3 ATP receptors. CGRP IR was seen in varicose vagal nerve Wbers and in delicate non-vagal Wbers, both in close proximity to NEBs. VAChT immunostaining showed very weak IR in the NEB-related intraepithelial vagal sensory nerve terminals. nNOS-or VIP-ir nerve terminals could be observed at the base of pulmonary NEBs. While a single NEB can be contacted by multiple nerve Wber populations, it was clear that none of the so far characterized nerve Wber populations contacts all pulmonary NEBs. The present study revealed that mouse lungs harbor several populations of nerve terminals that may selectively contact NEBs. Although at present the physiological signiWcance of the innervation pattern of NEBs remains enigmatic, it is likely that NEBs are receptor-eVector end-organs that may host complex and/or multiple functional properties in normal airways. The neurochemical information on the innervation of NEBs in mouse lungs gathered in the present study will be essential for the interpretation of upcoming functional data and for the study of transgenic mice.
Acta Histochemica, 2004
The innervation of the respiratory tract of amphibians is still poorly understood. Therefore, the respiratory tracts of the frogs Rana esculenta and Discoglossus pictus have been investigated in order to describe non-adrenergic non-cholinergic (NANC) and adrenergic innervation, and the localization of neuromediators that are possibly involved. Immunohistochemical staining of many bioactive substances was found in neuroepithelial cells of the buccopharynx, larynx, lung septa, nerves and neurons throughout the airway system. The findings indicate the occurrence of vasoactive intestinal peptide (VIP)-immunopositive nerve fibers in fibromuscular septa and the vasculature, nitrergic innervation of the large pulmonary veins showing a plexus of nNOS-immunopositive nerve fibers that also innervate the lung wall and the localization of neuronal nitric oxide synthase (nNOS) in neurons in the lung wall. In addition, laryngeal blood vessels and small arteries in the wall of septa that form capillary networks are supplied by enkephalin-immunopositive nerve terminals. We conclude that the airway system of the two frog species studied is innervated by a parasympathetic NANC system. Adrenergic innervation was also found that was immunostained for tyrosine hydroxylase. Adrenergic fibers were mainly present in muscles in septal edges, arteries present in septa and the wall of the lung. It is suggested that nNOS-positive and leu-enkephalin-positive neurons mediate vasodilation via the release of NO, but the nature of the NANC innervation remains obscure. Despite the many pharmacological studies of the lungs of amphibians, the physiological role of pulmonary autonomic innervation remains poorly understood.
Dual Sensory Innervation of Pulmonary Neuroepithelial Bodies
American Journal of Respiratory Cell and Molecular Biology, 2003
The correlation between the physiologically and morterminals that selectively contact pulmonary neuroepithelial phologically defined lung receptors, however, is far from bodies (NEBs) in rat lungs were investigated after chemical satisfactory. Although the number of studies dealing with denervation with capsaicin and compared with control lungs.
Functional morphology of pulmonary neuroepithelial bodies: Extremely complex airway receptors
The Anatomical Record, 2002
Innervated groups of neuroendocrine cells, called neuroepithelial bodies (NEBs), are diffusely spread in the epithelium of intrapulmonary airways in many species. Our present understanding of the morphology of NEBs in mammalian lungs is comprehensive, but none of the proposed functional hypotheses have been proven conclusively. In recent reviews on airway innervation, NEBs have been added to the list of presumed physiological lung receptors. Microscopic data on the innervation of NEBs, however, have given rise to conflicting interpretations. Using neuronal tracing, denervation, and immunostaining, we recently demonstrated that the innervation of NEBs is much more complex than the almost unique vagal nodose sensory innervation suggested by other authors. The aim of the present work is to summarize our present understanding about the origin and chemical coding of the profuse nerve terminals that selectively contact pulmonary NEBs. A thorough knowledge of the complex interactions between the neuroendocrine cells and at least five different nerve fiber populations is essential for defining the position(s) of NEBs among the many pulmonary receptors characterized by lung physiologists. Anat Rec Part A 270A: 25-40, 2003.
Brain Research, 1973
Electrical activity of single cells was recorded extracellularly in the vicinity of the solitary tract complex in the medulla oblongata ofpentobarbital anaesthetized, paralysed cats. The anatomical location and gross morphological properties of some of the neurones were determined by a fluorescent dye (Procion Yellow) injection technique. (2) Of a total of 279 cells studied, 261 ceils fired rhythmically with some phase of the respiratory cycle, i.e., respiratory neurones. Most respiratory neurones (238 cells) discharged in phase with the phrenic, i.e., they were inspiratory neurones. (3) Most of the 73 anatomically identified cells were found in the ventrolateral nucleus of the solitary tract which proved a somewhat heterogeneous nucleus with a roughly equal mixture of 'inspiratory-vagal', 'inspiratory-non-vagal-spinal' cells along with a few 'inspiratory-expiratory', expiratory and non-respiratory neurones. (4) Inspiratory neurones could be divided into 2 main groups on the basis of their vagal and spinal connections: (1) inspiratory neurones driven by electrical stimuli to the cervical vagus and influenced by lung inflations; (2) inspiratory neurones not influenced by vagal afferents but driven with short latency from the ventrolateral columns of the contralateral side of the spinal cord. (5) The 'inspiratory-vagal' cells showed inspiratory activity even when lung expansion in the inspiratory phase was prohibited, thus resembling the R/~ cells of von Baumgarten and Kanzow 6.