Innervation and Neurotransmitter Localization in the Lung of the Nile bichirPolypterus bichir bichir (original) (raw)
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Innervation of lung and heart in the ray-finned fish, bichirs
Acta Histochemica, 2009
Anatomical and functional studies of the autonomic innervation in the lung and the heart of the bichirs are lacking. The present review paper describes the presence of nerve fibers located in the muscle layers of the lung and its submucosa, the collection of unipolar neurons found in the submucosal and muscle layers of the glottis in a bichir species (Polypterus bichir bichir). Putative oxygen chemoreceptive, neuroepithelial cells (NECs) in the lung mucosa are also included. The latter share many immunohistochemical characteristics similar to those observed in the carotid body and neuroepithelial bodies of mammals. A packed collection of paraganglion cells is located within the trunk of the pulmonary vagus nerves. The paper also examines the occurrence of intracardiac neurons and nerve fibers in the heart of the above species. These studies show that various neurotransmitters may indicate different patterns of innervation in the lung and the heart of the bichirs. However, there is still much to be discovered about the lung and cardiovascular nervous control of these primitive fishes.
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, 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.
Acta Histochemica, 2008
Immunohistochemical localisation of neurotransmitters was used to determine the distribution of unipolar neurons and neuroepithelial cells (NECs) in the respiratory tract of the bichir, Polypterus bichir bichir. NECs were commonly encountered in the mucociliated epithelium of the lung. Unipolar neurons were located in the submucosal and muscle layers of the glottis. The results suggest the presence of tyrosine hydroxylase (TH) and nNOS immunoreactivities in NECs. In addition, ACh-E/nNOS and TH/nNOS nerve fibers were also found associated with these cells. Unipolar neuronal cells showed a chemical code including the presence of 5-HT, ACh-E, peptides and P 2 Â 2 receptors. The present findings indicate that nitric oxide (NO) is a primitive transmitter of neuroepithelial oxygen-sensitive chemoreceptor cells together with acetylcholine. The coexistence of ACh-E with other substances in the unipolar neurons, but not with NO, may be a property of vagal postganglionic neurons since the emergence of the cranial autonomic pathways in the earliest vertebrates. It would be interesting to know about the provenance of the nerves in contact with NECs, which appear to have a complex innervation pattern.
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.
Innervation of crab-eating monkey trachealis muscle determined in vitro
Respiration physiology, 1988
Strips of smooth muscle from the cervical tracheae of six adult male crab-eating monkeys (Macaca fascicularis) were studied in jacketed 25 ml organ baths filled with Krebs-bicarbonate solution maintained at 37 degrees C and gassed with 5% CO2 in oxygen. Isometric tissue tension increased in response to electrical field stimulation (18 V, 25 Hz, 0.5 msec), norepinephrine in the presence of propranolol, acetylcholine and histamine. Atropine abolished the contractile response to electrical stimulation. Tissues that were contracted with acetylcholine or pretreated with atropine then contracted with histamine relaxed when stimulated electrically. The relaxation was unaffected by propranolol but was abolished by tetrodotoxin. Isoproterenol relaxed tissues that were contracted with histamine, but failed to relax histamine-contracted tissues that had been pretreated with propranolol. Norepinephrine did not change isometric tension in untreated tissues or tissues pretreated with phentolamine...
Neuroscience Letters, 1998
The supramedullary cells (SMCs) are spinal neurons lying at the dorsal surface of teleosts. In the present study, we examined whether the SMCs of the puffer fish (Takifugu niphobles) might express gastrin/cholecystokinin-immunoreactivity, as observed in some other teleosts. All the SMCs were immunoreactive for gastrin/cholecystokinin. On the other hand, many immunoreactive varicose nerve fibers were also found terminating in the mucous glands in the skin. In addition, immunoreactive fibers were sparsely distributed in the epidermal layer. No neuronal cells other than the SMCs showed gastrin/cholecystokinin-immunoreactivity centrally or peripherally. The results suggest that gastrin/cholecystokinin-immunoreactive axons in the cutaneous mucous glands and epidermal layer are axons of the SMCs. In view of the present findings, the possible nature of SMCs was discussed.