Ionic Channels
Mostrando 13-24 de 315 artigos, teses e dissertações.
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13. Modulação da secreção de insulina em ilhotas de Langerhans pela crotoxina-like de Crotalus durissus collilineatus e suas subunidades
The crotoxin results from phospholipase A2 (PLA2) and crotapotin interaction. The PLA: acts in the membrane phospholipids generating arachidonic acid (AA). Venom PLA2 has been used as a pharmacological tool to identify target protein, mammalian receptor, and physiological cellular function. Therefore, the aim of this work was to study the role of crotoxin-li
Publicado em: 2002
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14. Espalhamento Raman dependente da temperatura no condutor superionico B-Eucrypte
By using Raman scattering techniques, we have studied the normal modes of vibration and the dynamics of the ionic motion in the superionic conductor b-Eucryptite, as a function of temperature, from room temperature to ~ 750ºC. Our results have proved that the high ionic conductivity it displays (~ 10-2 W-1cm-1, at 600ºC), can be explained in terms of the h
Publicado em: 1980
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15. Temperature dependence of the four ionic processes of spike electrogenesis in eel electroplaques.
Spike electrogenesis of eel electroplaques involves four ionic processes which are controlled by the membrane potential. A threshold depolarization causes normally closed Na permselective channels to open (Na-activation) and normally open K channels to close (K-inactivation). The Na channels then close (Na-inactivation), and as the spike is terminated, the K
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16. A molecular blueprint for the pore-forming structure of voltage-gated calcium channels.
A protein that imitates the sequence of a highly conserved segment predicted to line the pore of dihydropyridine-sensitive L-type calcium channels was designed and synthesized. Single-channel conductance properties were studied in planar lipid bilayers. The synthetic protein emulates the ionic conductance, ionic selectivity, and pharmacological properties of
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17. Altered ion channel conductance and ionic selectivity induced by large imposed membrane potential pulse.
The effects of large magnitude transmembrane potential pulses on voltage-gated Na and K channel behavior in frog skeletal muscle membrane were studied using a modified double vaseline-gap voltage clamp. The effects of electroconformational damage to ionic channels were separated from damage to lipid bilayer (electroporation). A 4 ms transmembrane potential p
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18. Hydrodynamic model of temperature change in open ionic channels.
Most theories of open ionic channels ignore heat generated by current flow, but that heat is known to be significant when analogous currents flow in semiconductors, so a generalization of the Poisson-Nernst-Planck theory of channels, called the hydrodynamic model, is needed. The hydrodynamic theory is a combination of the Poisson and Euler field equations of
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19. Enhancement of ionic currents through voltage-gated channels in the mouse oocyte after fertilization
1. The changes of voltage-gated ion channels in the mouse oocyte after fertilization were investigated under voltage clamp.
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20. G-protein modulation of N-type calcium channel gating current in human embryonic kidney cells (HEK 293).
1. Voltage-dependent inhibition of N-type calcium currents by G-proteins contributes importantly to presynaptic inhibition. To examine the effect of G-proteins on key intermediary transitions leading to channel opening, we measured both gating and ionic currents arising from recombinant N-type channels (alpha 1B, beta 1b and alpha 2) expressed in transiently
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21. Revisiting the ionic selectivity of Na+ channels.
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22. Beating irregularity of single pacemaker cells isolated from the rabbit sinoatrial node.
Single pacemaker heart cells discharge irregularly. Data on fluctuations in interbeat interval of single pacemaker cells isolated from the rabbit sinoatrial node are presented. The coefficient of variation of the interbeat interval is quite small, approximately 2%, even though the coefficient of variation of diastolic depolarization rate is approximately 15%
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23. Origin of delayed outward ionic current in charge movement traces from frog skeletal muscle.
1. Non-linear membrane ionic current was studied in highly stretched cut frog twitch fibres in a double Vaseline-gap voltage clamp chamber, with the internal solution containing 0.1 mM EGTA and the external solution containing Cl- as the major anion. After the Na+ currents was abolished by TTX in the external solution and the K+ currents were suppressed by e
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24. Effects of activin A on ionic channels in human FSH-secreting tumour cells.
1. Effects of activin A on ionic channels were examined in human FSH-secreting tumour cells using electrophysiological techniques. 2. Under voltage clamp with the conventional whole-cell clamp technique, the voltage-gated Na+ channel, the T- and L-type Ca2+ channels, the delayed K+ channel and the A-channel were observed. 3. With the nystatin-perforated whol