The Langerhans receptor of Oikopleura (Tunicata: Larvacea)

1979 ◽  
Vol 59 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Q. Bone ◽  
K. P. Ryan
Keyword(s):  
Epithelial Cells ◽  
Gap Junctions ◽  
Mechanical Stimulation ◽  
Action Potentials ◽  
Electrical Synapses ◽  
Locomotor Rhythm ◽  
Receptor Cells ◽  
Stimulation Of

The bristle-bearing receptors on either side of the trunk in Oikopleura are connected to the caudal ganglion by the axons of central cells which form electrical synapses (gap junctions) at the bases of the receptor cells. The same axons also form similar synapses with epithelial cells adjacent to the receptors. Direct mechanical stimulation of the receptor processes evokes changes in the locomotor rhythm of the same kind as evoked by action potentials propagated in the epithelial cells. This remarkable arrangement is suggested to be a consequence of the reduced numbers of cells in larvaceans.

scholarly journals Mechanical stimulation and intercellular communication increases intracellular Ca2+ in epithelial cells.

1990 ◽  
Vol 1 (8) ◽  
pp. 585-596 ◽  
Author(s):  
M J Sanderson ◽  
A C Charles ◽  
E R Dirksen
Keyword(s):  
Epithelial Cells ◽  
Respiratory Tract ◽  
Gap Junctions ◽  
Mechanical Stimulation ◽  
Intercellular Communication ◽  
Calcium Concentration ◽  
Ciliated Cells ◽  
Inositol 1,4,5 Trisphosphate ◽  
Ciliated Epithelial Cells ◽  
Stimulation Of

Intercellular communication of epithelial cells was examined by measuring changes in intracellular calcium concentration ([Ca2+]i). Mechanical stimulation of respiratory tract ciliated cells in culture induced a wave of increasing Ca2+ that spread, cell by cell, from the stimulated cell to neighboring cells. The communication of these Ca2+ waves between cells was restricted or blocked by halothane, an anesthetic known to uncouple cells. In the absence of extracellular Ca2+, the mechanically stimulated cell showed no change or a decrease in [Ca2+]i, whereas [Ca2+]i increased in neighboring cells. Iontophoretic injection of inositol 1,4,5-trisphosphate (IP3) evoked a communicated Ca2+ response that was similar to that produced by mechanical stimulation. These results support the hypothesis that IP3 acts as a cellular messenger that mediates communication through gap junctions between ciliated epithelial cells.

scholarly journals Intercellular calcium signaling via gap junctions in glioma cells.

1992 ◽  
Vol 118 (1) ◽  
pp. 195-201 ◽  
Author(s):  
A C Charles ◽  
C C Naus ◽  
D Zhu ◽  
G M Kidder ◽  
E R Dirksen ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Calcium Signaling ◽  
Single Cell ◽  
Mechanical Stimulation ◽  
Glioma Cells ◽  
C6 Glioma Cells ◽  
Dye Coupling ◽  
C6 Cells ◽  
Junction Protein ◽  
Stimulation Of

Calcium signaling in C6 glioma cells in culture was examined with digital fluorescence video microscopy. C6 cells express low levels of the gap junction protein connexin43 and have correspondingly weak gap junctional communication as evidenced by dye coupling (Naus, C. C. G., J. F. Bechberger, S. Caveney, and J. X. Wilson. 1991. Neurosci. Lett. 126:33-36). Transfection of C6 cells with the cDNA encoding connexin43 resulted in clones with increased expression of connexin43 mRNA and protein and increased dye coupling, as well as markedly reduced rates of proliferation (Zhu, D., S. Caveney, G. M. Kidder, and C. C. Naus. 1991. Proc. Natl. Acad. Sci. USA. 88:1883-1887; Naus, C. C. G., D. Zhu, S. Todd, and G. M. Kidder. 1992. Cell Mol. Neurobiol. 12:163-175). Mechanical stimulation of a single cell in a culture of non-transfected C6 cells induced a wave of increased intracellular calcium concentration ([Ca2+]i) that showed little or no communication to adjacent cells. By contrast, mechanical stimulation of a single cell in cultures of C6 clones expressing transfected connexin43 cDNA induced a Ca2+ wave that was communicated to multiple surrounding cells, and the extent of communication was proportional to the level of expression of the connexin43 cDNA. These results provide direct evidence that intercellular Ca2+ signaling occurs via gap junctions. Ca2+ signaling through gap junctions may provide a means for the coordinated regulation of cellular function, including cell growth and differentiation.

scholarly journals Some Factors in the Activation of Crab Movement Receptors

1963 ◽  
Vol 40 (1) ◽  
pp. 157-169
Author(s):  
MARTIN MENDELSON
Keyword(s):  
Electrical Activity ◽  
Mechanical Stimulation ◽  
High Frequency ◽  
Action Potentials ◽  
High Concentration ◽  
Low Concentration ◽  
Receptor Cells ◽  
Considerable Distance ◽  
Distal Process ◽  
Long Duration

1. The activation of movement receptors in Pachygrapsus crassipes is examined. 2. Lengthening and shortening of the elastic strand of the propodite-dactylopodite (PD) organ are respectively the adequate stimuli for movement receptors responding uniquely either to closing or opening. These stimuli are also effective on the isolated PD organ. Twisting of the strand is without effect. 3. Intracellular records from the receptor cells show apparent intermittent generator potentials during effective stimulation. No electrical activity is observed at sub-threshold speeds or during movement in the inappropriate direction. The action potentials are initiated in the distal process at a considerable distance from the soma. 4. Nicotine applied to the PD organ in high concentration elicits spike discharges of high frequency and long duration; it has no effect when applied to the axons. Applied to the PD organ in low concentration it potentiates the effect of mechanical stimulation without itself eliciting spikes. 5. These findings are discussed in relation to the structure of the receptor endings and a mechanism is tentatively suggested to account for the unidirectional sensitivity.

A role for Ca(2+)-conducting ion channels in mechanically-induced signal transduction of airway epithelial cells

1994 ◽  
Vol 107 (11) ◽  
pp. 3037-3044 ◽  
Author(s):  
S. Boitano ◽  
M.J. Sanderson ◽  
E.R. Dirksen
Keyword(s):  
Epithelial Cells ◽  
Mechanical Stimulation ◽  
Airway Epithelial Cells ◽  
Effective Concentration ◽  
Channel Blockers ◽  
Airway Epithelial ◽  
Free Medium ◽  
Half Maximal Effective Concentration ◽  
Induced Signal ◽  
Stimulation Of

Mechanical stimulation of a single cell in a cultured monolayer of airway epithelial cells initiates an intercellularly communicated increase in intracellular Ca2+ concentration ([Ca2+]i) that propagates radically through adjacent cells via gap junctions, forming an intercellular Ca2+ wave. Mechanically-induced intercellular Ca2+ waves also occur in the absence of extracellular Ca2+. However, in Ca(2+)-free medium an increase in [Ca2+]i of the stimulated cell does not occur. Thus, mechanically-induced [Ca2+]i changes in the stimulated cell are influenced by the extracellular Ca2+ concentration. To investigate if a channel-mediated Ca2+ flux across the plasma membrane contributes to the elevation of [Ca2+]i in the stimulated cell we used digital image microscopy to measure mechanically-induced [Ca2+]i changes in the presence of Ca2+ channel blockers. In Ca(2+)-free medium containing Gd3+ (20 microM) mechanical stimulation resulted in an [Ca2+]i increase in the stimulated cell. The delay time between mechanical stimulation and increase in [Ca2+]i of the stimulated cell was dependent on extracellular [Gd3+], with a half-maximal effective concentration of approximately 40 microM. Mechanical stimulation in Ca(2+)-free medium containing La3+ (10 microM) or Ni2+ (100 microM) gave similar results. Mechanical stimulation in Ca(2+)-free medium containing the dihydropyridine Ca2+ channel blockers nifedipine (10 microM) and nimodipine (10 microM) also resulted in an increase of [Ca2+]i of the stimulated cell. Mechanical stimulation of cells treated with thapsigargin to deplete intracellular Ca2+ stores, in the presence of 1.3 mM extracellular Ca2+, results in an increase in [Ca2+]i of the stimulated cell without the propagation of an intercellular Ca2+ wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell junctions in the excitable epithelium of bioluminescent scales on a polynoid worm: a freeze-fracture and electrophysiological study

1980 ◽  
Vol 41 (1) ◽  
pp. 341-368
Author(s):  
A. Bilbaut
Keyword(s):  
Epithelial Cells ◽  
Gap Junctions ◽  
Action Potentials ◽  
Electrophysiological Study ◽  
Freeze Fracture ◽  
Intercellular Junctions ◽  
Cell Junctions ◽  
Functional Roles ◽  
Electrophysiological Properties ◽  
Current Passage

The bioluminescent scales of the polynoid worm Acholoe are covered by a dorsal and ventral monolayer of epithelium. The luminous activity is intracellular and arises from the ventral epithelial cells, which are modified as photocytes. Photogenic and non-photogenic epithelial cells have been examined with regard to intercellular junctions and electrophysiological properties. Desmosomes, septate and gap junctions are described between all the epithelial cells. Lanthanum impregnation and freeze-fracture reveal that the septate junctions belong to the pleated-type found in molluscs, arthropods and other annelid tissues. Freeze-fractured gap junctions show polygonal arrays of membrane particles on the P face and complementary pits on the E face. Gap junctions are of the P type as reported in vertebrate, mollusc and some annelid tissues. Intracellular current passage also induces propagated non-overshooting action potentials in all the epithelial cells; in photocytes, an increase of injected current elicits another response which is a propagated 2-component overshooting action potential correlated with luminous activity. This study shows the coexistence of septate and gap junctions in a conducting and excitable invertebrate epithelium. The results are discussed in relation to the functional roles of intercellular junctions in invertebrate epithelia. It is concluded that the gap junctions found in this excitable epithelium represent the structural sites of the cell-to-cell propagation of action potentials.

scholarly journals Mechanical stimulation of epithelial cells using polypyrrole microactuators

Lab on a Chip ◽  
2011 ◽  
Vol 11 (19) ◽  
pp. 3287 ◽  
Author(s):  
Karl Svennersten ◽  
Magnus Berggren ◽  
Agneta Richter-Dahlfors ◽  
Edwin W. H. Jager
Keyword(s):  
Epithelial Cells ◽  
Mechanical Stimulation ◽  
Stimulation Of

Sodium-dependent receptor current in a new mechanoreceptor preparation

1994 ◽  
Vol 72 (6) ◽  
pp. 3026-3028 ◽  
Author(s):  
M. Juusola ◽  
E. A. Seyfarth ◽  
A. S. French
Keyword(s):  
Mechanical Stimulation ◽  
Action Potentials ◽  
Time Course ◽  
Receptor Potential ◽  
Sodium Ions ◽  
Similar Time ◽  
Sodium Dependent ◽  
Restricted Environment ◽  
Intracellular Microelectrodes ◽  
Stimulation Of

1. Intracellular microelectrodes recorded the receptor potential and receptor current in the neurons of spider slit sense organs during mechanical stimulation of the slits. 2. Mechanical stimulation produced two patterns of action potential discharge, corresponding to the two groups of neurons described previously by electrical stimulation. 3. Tetrodotoxin eliminated the action potentials and revealed a receptor potential with both static and adapting components. Voltage clamp gave an inward receptor current with a similar time course. 4. Replacement of sodium ions in the bath reversibly eliminated the receptor current, indicating that it is carried by sodium ions. However, this effect was comparatively slow, suggesting that the tips of the sensory dendrites lie in a chemically restricted environment.

Action potentials resulting from mechanical stimulation of pea epicotyls

Planta ◽  
1971 ◽  
Vol 97 (2) ◽  
pp. 106-115 ◽  
Author(s):  
Barbara Gillespie Pickard
Keyword(s):  
Mechanical Stimulation ◽  
Action Potentials ◽  
Stimulation Of
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