Ultrasonic production of reversible changes in the electrical parameters of isolated frog skin

1976 ◽  
Vol 60 (1) ◽  
pp. 225-229 ◽  
Author(s):  
A. J. Coble ◽  
F. Dunn
Keyword(s):  
Frog Skin ◽  
Electrical Parameters

Effect of furosemide on the electrical parameters of frog skin

1982 ◽  
Vol 243 (6) ◽  
pp. F581-F587 ◽  
Author(s):  
A. Corcia ◽  
S. R. Caplan
Keyword(s):  
Active Transport ◽  
Frog Skin ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Relative Increase ◽  
Electrical Potential Difference ◽  
Electrical Parameters ◽  
Active Conductance ◽  
Solution Bathing

When added to the mucosal solution bathing isolated frog skin at concentrations ranging from 5 X 10(-4) to 3 X 10(-3) M, the diuretic furosemide increased both the active transport of sodium and the electrical potential difference across the tissue in a dose-dependent way. The same effect was observed in chloride-free solutions. Mucosal furosemide also decreased the passive unidirectional fluxes of chloride. We believe that as far as electrical parameters are concerned mucosal furosemide has a double effect in frog skin: it increases the active conductance to sodium across the mucosal membrane, thus increasing active transport, and decreases the passive permeability to chloride, thus altering the passive conductance of the skin. The relative increase in short-circuit current was, however, invariably greater than the increase of the active conductance, suggesting the influence of yet a third effect. The effect of mucosal furosemide on active sodium transport was blocked by amiloride (5 X 1-(-5) M) and was independent of vasopressin. Qualitatively the effect was similar to the effect produced by triphenylmethylphosphonium ion.

scholarly journals Correlation between damping coefficients and externally injected currents in oscillations produced by lithium ions in frog skin

1988 ◽  
Vol 135 (1) ◽  
pp. 51-64
Author(s):  
C. A. Baptista ◽  
M. P. Ramos ◽  
C. H. de Jesus
Keyword(s):  
Electromotive Force ◽  
Frog Skin ◽  
Electrical Parameters ◽  
Qualitative Behaviour ◽  
Lithium Ions ◽  
Experimental Conditions ◽  
Damping Coefficients ◽  
Mucosal Side ◽  
Epithelial Resistance

Oscillations in the electrical parameters elicited by Li+ added to the mucosal side of frog skin in vitro were studied under different experimental conditions. The correlation between the damping coefficient and the size of the externally injected current was ascertained. The size of the overall epithelial resistance in NaCl-Ringer seems to be a good indicator of the qualitative behaviour of the skin in the presence of Li+: the higher the resistance the less probable the occurrence of oscillations. Addition of amiloride allowed the calculation of the electromotive force in Na+- and Li+-Ringer. Calculations of the ‘total equivalent inductance’ and ‘total equivalent capacitance’ of an oscillating skin were made using resistance values (R), damping coefficients (sigma) and frequency of oscillation (omega).

Effects of mucosal lanthanum on electrical parameters of isolated frog skin

1979 ◽  
Vol 379 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Henri Goudeau ◽  
Jaime Wietzerbin ◽  
Claude M. Gary-Bobo
Keyword(s):  
Frog Skin ◽  
Electrical Parameters

Analysis of Individual Frog Skin Extracts from Dendrobates Auratus with Capillary NMR

Planta Medica ◽  
2013 ◽  
Vol 79 (10) ◽  
Author(s):  
RW Fitch ◽  
A Weng ◽  
RA Saporito
Keyword(s):  
Frog Skin ◽  
Dendrobates Auratus

The Influence Of The Led Luminaires Electrical Parameters On Their Correlated Colour Temperature During Operation Mode

2020 ◽  
pp. 89-96
Author(s):  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov ◽  
Sergei V. Prytkov ◽  
Sergei Yu. Grigorovich ◽  
Anastasia V. Kapitonova ◽  
...  
Keyword(s):  
Operation Mode ◽  
Light Sources ◽  
Electrical Parameters ◽  
Colour Temperature ◽  
Radiation Spectra ◽  
Service Period ◽  
Close Proximity ◽  
Definition Of ◽  
Comprehensive Study

The article describes the results of comprehensive study aiming at increase of quality of LED luminaires and definition of the nature of changes in their correlated colour temperature (CCT) in the course of operation. Dependences of CCT of LED luminaires with remote and close location of phosphor for 10 thousand hours of operation in different electric modes were obtained; the results of comparison between the initial and final radiation spectra of the luminaires are presented; using mathematical statistics methods, variation of luminaire CCT over the service period claimed by the manufacturer is forecast; the least favourable electric operation modes with the highest CCT variation observed are defined. The obtained results have confirmed availability of the problem of variation of CCT of LED luminaires during their operation. Possible way of its resolution is application of more qualitative and therefore expensive LEDs with close proximity of phosphor or LEDs with remote phosphor. The article may be interesting both for manufacturers and consumers of LED light sources and lighting devices using them.

The Sigma-1 Receptor Ligands Chlorpromazine and Trifluoperazine Inhibit Na+ Transport in Frog Skin Epithelium

BIOPHYSICS ◽  
2020 ◽  
Vol 65 (5) ◽  
pp. 784-787
Author(s):  
A. V. Melnitskaya ◽  
Z. I. Krutetskaya ◽  
V. G. Antonov ◽  
N. I. Krutetskaya
Keyword(s):  
Frog Skin ◽  
Receptor Ligands ◽  
Na Transport ◽  
Sigma 1 Receptor ◽  
Skin Epithelium ◽  
Frog Skin Epithelium ◽  
Sigma 1

The melanocyte stimulating activity of N-nitroso-2-chloroethyl-carbamoyl derivatives of α-melanotropin fragments

1988 ◽  
Vol 53 (11) ◽  
pp. 2574-2582 ◽  
Author(s):  
Hedvig Medzihradszky-Schweiger ◽  
Helga Süli-Vargha ◽  
József Bódi ◽  
Kálmán Medzihradszky
Keyword(s):  
Biological Activity ◽  
Active Site ◽  
Frog Skin ◽  
Terminal Sequence ◽  
Subsequent Reaction ◽  
Affinity Labels ◽  
Derivatives Of

A number of N-nitroso-2-chloroethyl-carbamoyl (Q(NO)) derivatives of α-melanotropin fragments have been synthesized and their effect on the frog skin melanocytes studied. Peptides substituted in this way possess the biological activity of the parent compounds, indicating that they preserved their receptor recognizing ability. These compounds can therefore serve as affinity labels. Some of these derivatives, related to the C-terminal sequence of α-melanotropin show prolonged darkening reaction, which does not influence the subsequent reaction of melanocytes with α-melanotropin. The Q(NO)-derivative of a fragment derived from the classical active site of the hormone shows, however, inhibition of the effect of α-melanotropin. It can be concluded that the latter peptide acts through the melanotropin receptor, while others, related to the C-terminal sequence of the hormone through another mechanism.

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