Internal morphology of the gill of a loricariid fish, Hypostomus plecostomus: arterio-arterial vasculature and muscle organization

1995 ◽  
Vol 73 (12) ◽  
pp. 2259-2265 ◽  
Author(s):  
M. N. Fernandes ◽  
S. A. Perna
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Striated Muscle ◽  
Light And Electron Microscopy ◽  
Muscle Cells ◽  
Muscle Fibres ◽  
Striated Muscles ◽  
Vascular Perfusion ◽  
Hypoxic Conditions ◽  
Adductor Muscles

The structural organization of the interbranchial septum of the gill arch of the air-breathing loricariid fish Hypostomus plecostomus was examined using light and electron microscopy. In the middle of the interbranchial septum, an extensive interconnection was found between the afferent primary arteries from successive and opposing primary lamellae. The blood circulates among numerous trabeculae consisting of connective tissue, smooth muscle cells, and collagen fibres. A sheet of smooth muscle cells is localized at the borders of these interconnected primary arteries and joins the cartilage rod from one primary lamella to the adjacent one on the same hemibranch. The adductor muscles are restricted to the distal end of the interbranchial septum and consist of transverse and oblique striated muscle fibres fixed to the cartilage rod from the primary lamella of opposite hemibranchs. The arrangement of these muscle fibres suggests a double movement of adduction: approximation of the tips of the primary lamellae of opposing hemibranchs and reduction of the space between adjacent primary lamellae of the same hemibranch. The action of both smooth and striated muscles reduces the interconnecting vascular septal space between the primary arteries, which may allow fine adjustment of vascular perfusion of the distal part of the filaments as an adaptation for better blood flow under hypoxic conditions.

scholarly journals Force: velocity relationship in single isolated toad stomach smooth muscle cells.

1987 ◽  
Vol 89 (5) ◽  
pp. 771-789 ◽  
Author(s):  
D M Warshaw
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Length Change ◽  
Force Transducer ◽  
Cell Length ◽  
Shortening Velocity ◽  
Cross Sectional ◽  
Cross Bridges

The relationship between force and shortening velocity (F:V) in muscle is believed to reflect both the mechanics of the myosin cross-bridge and the kinetics of its interaction with actin. To date, the F:V for smooth muscle cells has been inferred from F:V data obtained in multicellular tissue preparations. Therefore, to determine F:V in an intact single smooth muscle cell, cells were isolated from the toad (Bufo marinus) stomach muscularis and attached to a force transducer and length displacement device. Cells were electrically stimulated at 20 degrees C and generated 143 mN/mm2 of active force per muscle cross-sectional area. At the peak of contraction, cells were subjected to sudden changes in force (dF = 0.10-0.90 Fmax) and then maintained at the new force level. The force change resulted in a length response in which the cell length (Lcell) rapidly decreased during the force step and then decreased monotonically with a time constant between 75 and 600 ms. The initial length change that coincided with the force step was analyzed and an active cellular compliance of 1.9% cell length was estimated. The maintained force and resultant shortening velocity (V) were fitted to the Hill hyperbola with constants a/Fmax of 0.268 and b of 0.163 Lcell/s. Vmax was also determined by a procedure in which the cell length was slackened and the time of unloaded shortening was recorded (slack test). From the slack test, Vmax was estimated as 0.583 Lcell/s, in agreement with the F:V data. The F:V data were analyzed within the framework of the Huxley model (Huxley. 1957. Progress in Biophysics and Biophysical Chemistry. 7:255-318) for contraction and interpreted to indicate that in smooth muscle, as compared with fast striated muscle, there may exist a greater percentage of attached force-generating cross-bridges.

A survey of the new findings presented and the discussions arising during sessions I, II and lII

1973 ◽  
Vol 265 (867) ◽  
pp. 157-165 ◽  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Smooth Muscles ◽  
Muscle Cells ◽  
Muscle Physiology ◽  
Muscle Fibres ◽  
New Findings ◽  
Separate Identity ◽  
Skeletal Muscle Fibres ◽  
Passive Electrical Properties

One of the earliest studies on the physiology of smooth muscle was that reported by Engelmann over 100 years ago. In setting the stage for this discussion on new developments in smooth muscle physiology, Professor Bozler recalled Engelmann’s description of the ureter as a ‘giant hollow muscle fibre’. Recent work on the passive electrical properties of smooth muscle has shown that Engelmann’s concept of the syncytial behaviour of smooth muscle is true for a great many smooth muscles - perhaps for all vertebrate smooth muscles. When smooth muscle cells come into contact they interact with each other so as to form a tissue. In this sense, a community of smooth muscle cells is analogous with the liver, epithelial tissues and the heart. One can contrast this ‘collective’ behaviour of smooth muscle cells with the separate identity maintained by most nerve cells and skeletal muscle fibres.

Tyrosine kinase receptor activation inhibits NPR-C in lung arterial smooth muscle cells

2001 ◽  
Vol 281 (1) ◽  
pp. L155-L163 ◽  
Author(s):  
Ju-Zhong Sun ◽  
Suzanne Oparil ◽  
Pamela Lucchesi ◽  
John A. Thompson ◽  
Yiu-Fai Chen
Keyword(s):  
Smooth Muscle ◽  
Growth Factors ◽  
Tyrosine Kinase ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Tyrosine Kinase Receptors ◽  
Mrna Levels ◽  
Ang Ii ◽  
Hypoxic Conditions ◽  
Arterial Smooth Muscle Cells

We have previously demonstrated that expression of the atrial natriuretic peptide (ANP) clearance receptor (NPR-C) is reduced selectively in the lung of rats and mice exposed to hypoxia but not in pulmonary arterial smooth muscle cells (PASMCs) cultured under hypoxic conditions. The current study tested the hypothesis that hypoxia-responsive growth factors, fibroblast growth factors (FGF-1 and FGF-2) and platelet-derived growth factor-BB (PDGF-BB), that activate tyrosine kinase receptors can reduce expression of NPR-C in PASMCs independent of environmental oxygen tension. Growth-arrested rat PASMCs were incubated under hypoxic conditions (1% O2) for 24 h; with FGF-1, FGF-2, or PDGF-BB (0.1–20 ng/ml for 1–24 h); or with ANG II (1–100 nM), endothelin-1 (ET-1, 0.1 μM), ANP (0.1 μM), sodium nitroprusside (SNP, 0.1 μM), or 8-bromo-cGMP (0.1 mM) for 24 h under normoxic conditions. Steady-state NPR-C mRNA levels were assessed by Northern blot analysis. FGF-1, FGF-2, and PDGF-BB induced dose- and time-dependent reduction of NPR-C mRNA expression within 1 h at a threshold concentration of 1 ng/ml; hypoxia, ANG II, ET-1, ANP, SNP, or cGMP did not decrease NPR-C mRNA levels in PASMCs under the above conditions. Downregulation of NPR-C expression by FGF-1, FGF-2, and PDGF-BB was inhibited by the selective FGF-1 receptor tyrosine kinase inhibitor PD-166866 and mitogen-activated protein/extracellular signal-regulated kinase inhibitors U-0126 and PD-98059. These results indicate that activation of tyrosine kinase receptors by hypoxia-responsive growth factors, but neither hypoxia per se nor activation of G protein-coupled receptors, inhibits NPR-C gene expression in PASMCs. These results suggest that FGF-1, FGF-2, and PDGF-BB play a role in the signal transduction pathway linking hypoxia to altered NPR-C expression in lung.

scholarly journals The mammalian lacteal: its histological structure in relation to its physiological properties

1927 ◽  
Vol 102 (714) ◽  
pp. 110-118 ◽  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Living Condition ◽  
Muscle Fibres ◽  
Histological Structure ◽  
Physiological Properties ◽  
Living Preparation

One of us (H. W. F.) (7, 8) has already noted that the mesenteric lacteals contract on appropriate stimulation in a number of animals. He also observed in the guinea-pig and the rat that the vessels were rhythmically contractile. In the latter species the nuclei of circular muscle fibres in the lacteal wall could be seen in the living condition. The difficulties, however, of making out the part played by smooth muscle cells and nuclei in such contractions are very great in the living preparation. It was, therefore, resolved to supplement these observations on the living mesentery by others on fixed and stained material. In some cases the excised lacteal had actually been observed to contract in the living mesentery. The mesenteric lacteals of the cat have been taken as a type, and special attention has been paid to the distribution of smooth muscle fibres in the lymphatics in the various species studied.

Electron microscopy of the glio-vascular organization of the brain of octopus

1969 ◽  
Vol 255 (797) ◽  
pp. 13-32 ◽  
Keyword(s):  
Electron Microscopy ◽  
Smooth Muscle ◽  
Blood Vessels ◽  
Light And Electron Microscopy ◽  
Muscle Cells ◽  
Medium Size ◽  
Muscle Fibres ◽  
Special Importance ◽  
Form Complex ◽  
Large Neurons

The glio-vascular organization of the octopus brain has been studied by light and electron microscopy. The structure of the walls of the blood vessels has been described. Two types of neuroglia can be recognized, the fibrous and protoplasmic glia; also enigmatic dark cells. Most blood vessels in the neuropil are surrounded by extracellular zones containing collagen. These zones give off glio-vascular tunnels (strands) that penetrate the neuropil in a complex network. The extracellular zones and tunnels contain in addition to collagen, smooth muscle cells and fibrocytes. Glial processes surround the extracellular zones and incompletely partition them from the neuropil. The small neuronal perikarya have no glial folds around them. The medium-size cells have thin glial sheets or finger processes related to their surfaces, which may indent the cells to form small trophospongia. The large neurons of the suboesophageal lobe have complex glial sheaths interspersed with extracellular channels. Both penetrate the neurons to form complex trophospongia. A new form of extracellular material has been observed in these extracellular channels. The occurrence of trophospongia in vertebrate and invertebrate neurons may be correlated with the absence of dendrites. Special problems discussed include the nature of the trophospongial function, the question of fluid-filled extracellular zones and their possible function as lymph channels, and the presence in some of them of haemocyanin molecules identical with those in the blood vessels. Perhaps of special importance is the observation that the lobes of the octopus brain are permeated with extracellular tunnels containing smooth muscle fibres, but it still needs to be determined whether or not the muscle cells in the tunnels of the neuropil actively contract and massage the neuropil to facilitate metabolic and other exchanges.

scholarly journals Olfactory receptor Olfr78 (prostate-specific G protein-coupled receptor PSGR) expression in arterioles supplying skeletal and cardiac muscles and in arterioles feeding some murine organs

2021 ◽  
Author(s):  
Petra Mermer ◽  
Jörg Strotmann ◽  
Wolfgang Kummer ◽  
Renate Paddenberg
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
G Protein ◽  
Olfactory Receptor ◽  
Muscle Cells ◽  
Striated Muscles ◽  
Pressure Regulation ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

AbstractThe olfactory receptor Olfr78 (prostate-specific G protein-coupled receptor PSGR) is a member of the G protein-coupled receptor family mediating olfactory chemosensation, but it is additionally expressed in other tissues. Olfr78 expressed in kidney participates in blood pressure regulation, and in prostate it plays a role in the development of cancer. We here screened many organs/tissues of transgenic mice co-expressing β-galactosidase with Olfr78. X-gal-positive cells were detectable in smooth muscle cells of numerous arterioles of striated muscles (heart ventricles and skeletal muscles of various embryological origin). In addition, in most organs where we found expression of Olfr78 mRNA, X-gal staining was restricted to smooth muscle cells of small blood vessels. The dominant expression of Olfr78 in arteriolar smooth muscle cells supports the concept of an important role in blood pressure regulation and suggests a participation in the fine tuning of blood supply especially of striated muscles. This should be considered when targeting Olfr78 in other contexts such as prostate cancer.

Sign in / Sign up

Export Citation Format

Share Document