Vestibular Neuroanatomy

1979 ◽  
Vol 88 (5) ◽  
pp. 667-675 ◽  
Author(s):  
Richard R. Gacek
Keyword(s):  
Vestibular Nuclei ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Oculomotor Nucleus ◽  
Abducens Nucleus ◽  
Commissural Neurons ◽  
Commissural Pathways ◽  
Ocular Disorders ◽  
I Cells

The modern neuroanatomical technique of using a retrograde axoplasmic tracer (horseradish peroxidase) to label neurons has aided the revelation of several important connections in the vestibular system. The organization of the oculomotor nucleus and the existence of an interneuron in the abducens nucleus have importance in understanding some ocular disorders. A detailed description of the location of vestibulo-ocular neurons to individual extraocular muscles is now available which may provide a basis for understanding how these reflexes function normally and abnormally. Interconnections between the vestibular nuclei are provided by commissural neurons located in the superior, medial and group Y nuclei. These projections are probably of importance in vestibular compensation. A possible hypothesis of vestibular hair cell projection suggests that type I cells project over vestibulo-ocular neurons while type II cells project over commissural pathways.

scholarly journals Mechanical stretch activates piezo1 in caveolae of alveolar type I cells to trigger ATP release and paracrine stimulation of surfactant secretion from alveolar type II cells

2020 ◽  
Vol 34 (9) ◽  
pp. 12785-12804 ◽  
Author(s):  
Kathrin Diem ◽  
Michael Fauler ◽  
Giorgio Fois ◽  
Andreas Hellmann ◽  
Natalie Winokurow ◽  
...  
Keyword(s):  
Atp Release ◽  
Mechanical Stretch ◽  
Alveolar Type ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Alveolar Type Ii Cells ◽  
Surfactant Secretion ◽  
I Cells ◽  
Stimulation Of

scholarly journals Transitional human alveolar type II epithelial cells suppress extracellular matrix and growth factor gene expression in lung fibroblasts

2019 ◽  
Vol 317 (2) ◽  
pp. L283-L294 ◽  
Author(s):  
Kelly A. Correll ◽  
Karen E. Edeen ◽  
Rachel L. Zemans ◽  
Elizabeth F. Redente ◽  
Karina A. Serban ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Surfactant Protein ◽  
Lung Fibroblasts ◽  
Alveolar Type ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Alveolar Type Ii Cells ◽  
I Cells

Epithelial-fibroblast interactions are thought to be very important in the adult lung in response to injury, but the specifics of these interactions are not well defined. We developed coculture systems to define the interactions of adult human alveolar epithelial cells with lung fibroblasts. Alveolar type II cells cultured on floating collagen gels reduced the expression of type 1 collagen (COL1A1) and α-smooth muscle actin (ACTA2) in fibroblasts. They also reduced fibroblast expression of hepatocyte growth factor (HGF), fibroblast growth factor 7 (FGF7, KGF), and FGF10. When type II cells were cultured at an air-liquid interface to maintain high levels of surfactant protein expression, this inhibitory activity was lost. When type II cells were cultured on collagen-coated tissue culture wells to reduce surfactant protein expression further and increase the expression of some type I cell markers, the epithelial cells suppressed transforming growth factor-β (TGF-β)-stimulated ACTA2 and connective tissue growth factor (CTGF) expression in lung fibroblasts. Our results suggest that transitional alveolar type II cells and likely type I cells but not fully differentiated type II cells inhibit matrix and growth factor expression in fibroblasts. These cells express markers of both type II cells and type I cells. This is probably a normal homeostatic mechanism to inhibit the fibrotic response in the resolution phase of wound healing. Defining how transitional type II cells convert activated fibroblasts into a quiescent state and inhibit the effects of TGF-β may provide another approach to limiting the development of fibrosis after alveolar injury.

scholarly journals ULTRASTRUCTURE OF THE CAROTID BODY

1966 ◽  
Vol 30 (3) ◽  
pp. 563-578 ◽  
Author(s):  
T. J. Biscoe ◽  
W. E. Stehbens
Keyword(s):  
Blood Vessels ◽  
Schwann Cells ◽  
Carotid Body ◽  
Nerve Fibers ◽  
Nerve Endings ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Type I Cells ◽  
I Cells

An electron microscope investigation was made of the carotid body in the cat and the rabbit. In thin-walled blood vessels the endothelium was fenestrated. Larger vessels were surrounded by a layer of smooth muscle fibers. Among the numerous blood vessels lay groups of cells of two types covered by basement membranes. Aggregates of Type I cells were invested by Type II cells, though occasionally cytoplasmic extensions were covered by basement membrane only. Type I cells contained many electron-opaque cored vesicles (350 to 1900 A in diameter) resembling those in endocrine secretory cells. Type II cells covered nerve endings terminating on Type I cells and enclosed nerve fibers in much the same manner as Schwann cells. The nerve endings contained numerous microvesicles (∼500 A in diameter), mitochondria, glycogen granules, and a few electron-opaque cored vesicles. Junctions between nerve endings and Type I cells were associated with regions of increased density in both intercellular spaces and the adjoining cytoplasm. Cilia of the 9 + 0 fibril pattern were observed in Type I and Type II cells and pericytes. Nonmyelinated nerve fibers, often containing microvesicles, mitochondria, and a few electron-opaque cored vesicles (650 to 1000 A in diameter) were present in Schwann cells, many of which were situated close to blood vessels Ganglion cells near the periphery of the gland, fibrocytes, and segments of unidentified cells were also seen. It was concluded that, according to present concepts of the structure of nerve endings, those endings related to Type I cells could be efferent or afferent.

scholarly journals Lectin binding patterns to terminal sugars of rat lung alveolar epithelial cells.

1990 ◽  
Vol 38 (2) ◽  
pp. 233-244 ◽  
Author(s):  
D J Taatjes ◽  
L A Barcomb ◽  
K O Leslie ◽  
R B Low
Keyword(s):  
Epithelial Cells ◽  
Lectin Binding ◽  
Alveolar Epithelial Cells ◽  
Gold Complex ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Rat Lung ◽  
Alveolar Epithelial ◽  
I Cells

We used post-embedding cytochemical techniques to investigate the lectin binding profiles of rat lung alveolar epithelial cells. Sections from rat lung embedded in the hydrophilic resin Lowicryl K4M were incubated either directly with a lectin-gold complex or with an unlabeled lectin followed by a specific glycoprotein-gold complex. The binding patterns of the five lectins used could be divided into three categories according to their reactivity with alveolar epithelial cells: (a) the Limax flavus lectin and Ricinus communis I lectin bound to both type I and type II cell plasma membranes; (b) the Helix pomatia lectin and Sambucus nigra L. lectin bound to type II but not type I cells; and (c) the Erythrina cristagalli lectin reacted with type I cells but was unreactive with type II cells. The specificity of staining was assessed by control experiments, including pre-absorption of the lectins with various oligosaccharides and enzymatic pre-treatment of sections with highly purified glycosidases to remove specific sugar residues. The results demonstrate that these lectins can be used to distinguish between type I and type II cells and would therefore be useful probes for investigating cell dynamics during lung development and remodeling.

Effects of oligohydramnios on lung growth and maturation in the fetal rat

2002 ◽  
Vol 282 (3) ◽  
pp. L431-L439 ◽  
Author(s):  
Joseph A. Kitterman ◽  
Cheryl J. Chapin ◽  
Jeff N. Vanderbilt ◽  
Nicolas F. M. Porta ◽  
Louis M. Scavo ◽  
...  
Keyword(s):  
Fetal Lung ◽  
Alveolar Type ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lung Growth ◽  
Type I Cells ◽  
Fetal Lung Development ◽  
Fetal Rat ◽  
I Cells

Oligohydramnios (OH) retards fetal lung growth by producing less lung distension than normal. To examine effects of decreased distension on fetal lung development, we produced OH in rats by puncture of uterus and fetal membranes at 16 days of gestation; fetuses were delivered at 21 or 22 days of gestation. Controls were position-matched littermates in the opposite uterine horn. OH lungs had lower weights and less DNA, protein, and water, but no differences in saturated phosphatidylcholine, surfactant proteins (SP)-A and -B, and mRNA for SP-A, -B, -C, and -D. To evaluate effects on epithelial differentiation, we used RTI40 and RTII70, proteins specific in lung to luminal surfaces of alveolar type I and II cells, respectively. At 22 days of gestation, OH lungs had less RTI40 mRNA ( P < 0.05) and protein ( P < 0.001), but RTII70 did not differ from controls. With OH, type I cells (in proportion to type II cells) covered less distal air space perimeter ( P < 0.01). We conclude that OH, which retards lung growth, has little effect on surfactant and impedes formation of type I cells relative to type II cells.

A Study of the Enteric Plexuses in Some Amphibians

1951 ◽  
Vol s3-92 (17) ◽  
pp. 55-77
Author(s):  
MARGARET GUNN
Keyword(s):  
Myenteric Plexus ◽  
Proximal Part ◽  
Nerve Cells ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Nerve Fibres ◽  
Type I Cells ◽  
Splanchnic Nerves ◽  
I Cells

1. The extrinsic nerve-supply to the gut in the frog (Rana temporaria) is contained in the vagus and splanchnic nerves--both of which appear to contain parasympathetic and sympathetic fibres. 2. The vagus supplies the gut from the proximal part of the oesophagus to the most proximal part of the intestine. The splanchnic nerves supply the gut from the oesophagus to the rectum. 3. No vagal fibres accompany the splanchnic nerves. 4. A possible explanation is given for the variable effects produced on stimulation of the extrinsic nerves supplying the gut. 5. A plexus of nerve-fibres is present i n the submucosa which probably corresponds to Meissner's plexus of mammals, but no nerve-cells are present. 6. In the myenteric plexus the nerve-cells are commonly grouped int o ganglia in the oesophagus and stomach, but in theintestine the nerve-cells are fairly evenly distributed, distinct ganglia not being present. 7. Cells of three types have been found corresponding to Dogiel's three types. Type I cells are of two varieties: (a) large, strongly argyrophi l cells which are multi-polar possessing numerous short dendrites and a very prominent axon; (b)smaller cells having a prominent axon and often unipolar. Type I cells are enclosed in capsules. Type II cells are small multipolar cells with long dendrites. Type III cells are small multipolar cells with shorter dendrites and an axon bearing no collaterals. 8. Cells in the oesophagus and stomach are entirely of Type I. In the intestine these cells are present in fairly large numbers at the most proximal end, but throughout the rest of the intestine they only occur commonly close to the attachment of the mesentery, where they are found singly and fairly evenly spaced. 9. Cells of Types II and III occur only in the myenteric plexus of the intestine, where they are distributed fairly evenly, not forming distinct ganglia. 10. It is suggested that the Type II and III cells formed the original autonomic nerve plexus of the gut, the Type II cells being motor and the Type III sensory. The Type I cells are the post-ganglionic cells of the parasympathetic system and are an additional motor contribution to the plexus. 11. The endings of th e pre-ganglionic parasympathetic fibres on the ganglion cells may take any of three forms: (a) pericellular varicose endings which occur on the large variety of Typ e I cell; (b) pericapsular varicose endings which are borne by the smaller variety of Type I cell; and(c) club-shaped endings occurring on the larger Type I cells. 12. The type of synapse formed by the processes of cells of Types II and III consists of the simple endings of their processes on the cell bodies or dendrites of other cells, or the passing contact of their processes with the bodies of other cells. 13. Fine varicose fibrils have been observed on the surface of muscle-cells. These are presumably the distal ends of the cell processes and sympathetic fibres which form the motor endings. 14. The types of sensory endings which have been found are: (a) typical sensory varicose endings spread out in the submucosa of the oesophagus and rectum; those in the oesophagus originating from vagal fibres; and (b) Pacinian corpuscle in the sub-mucosa of the intestine. 15. The ‘interstitial cells of Cajal’ form an apparently anastomosing network in the gut-wall which appears to be distinct from the anastomosing Schwann plasmodium which covers the nerve-fibres.

scholarly journals UTP regulation of ion transport in alveolar epithelial cells involves distinct mechanisms

2009 ◽  
Vol 297 (3) ◽  
pp. L439-L454 ◽  
Author(s):  
Chuanxiu Yang ◽  
Lijing Su ◽  
Yang Wang ◽  
Lin Liu
Keyword(s):  
Ion Transport ◽  
Short Circuit ◽  
Alveolar Epithelial Cells ◽  
Alveolar Type ◽  
Channel Blockers ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Type I Cells ◽  
I Cells

UTP is known to regulate alveolar fluid clearance. However, the relative contribution of alveolar type I cells and type II cells to this process is unknown. In this study, we investigated the effects of UTP on ion transport in type I-like cell (AEC I) and type II-like cell (AEC II) monolayers. Luminal treatment of cell monolayers with UTP increased short-circuit current ( Isc) of AEC II but decreased Isc of AEC I. The Cl− channel blockers NPPB and DIDS inhibited the UTP-induced changes in Isc (Δ Isc) in both types of cells. Amiloride, an inhibitor of epithelial Na+ channels (ENaC), abolished the UTP-induced Δ Isc in AEC I, but not in AEC II. The general blocker of K+ channels, BaCl2, eliminated the UTP-induced Δ Isc in AEC II, but not in AEC I. The intermediate conductance (IKCa) blocker, clofilium, also blocked the UTP effect in AEC II. The signal transduction pathways mediated by UTP were the same in AEC I and AEC II. Furthermore, UTP increased Cl− secretion in AEC II and Cl− absorption in AEC I. Our results suggest that UTP induces opposite changes in Isc in AEC I and AEC II, likely due to the reversed Cl− flux and different contributions of ENaC and IKCa. Our results further imply a new concept that type II cells contribute to UTP-induced fluid secretion and type I cells contribute to UTP-induced fluid absorption in alveoli.

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