Zoeken
Zoeken kan via de modus 'eenvoudig zoeken' (één veld) of uitgebreid via 'geavanceerd zoeken' (meerdere velden). Zo kan je bv. zoeken op een combinatie van een auteursnaam (auteur), een jaartal (jaar) en een documenttype.
Boekenmand
Nuttige resultaten kan je aanvinken en toevoegen aan een mandje. De inhoud hiervan kan je exporteren of afdrukken (naar bv. PDF).
RSS
Op de hoogte blijven van nieuw toegevoegde publicaties binnen uw interessegebied? Dit kan door een RSS-feed (?) te maken van jouw zoekopdracht.
nieuwe zoekopdracht
Resting and active K+ channels in the squid axon membrane
Inoue, I. (1995). Resting and active K+ channels in the squid axon membrane, in: Abbott, N.J. et al. Cephalopod neurobiology: neuroscience studies in squid, octopus and cuttlefish. pp. 73-83
|
| Abstract |
Potassium currents (IK) were recorded from giant axons of squid, Sepioteuthis lessoniana under voltage clamp. The K+ accumulation in a space between outer membrane surface and surrounding Schwann cells layer, the so-called Frankenhauser-Hodgkin space (F-H space) due to K+ efflux was completely removed by immersing the nerve fibre in a high osmolarity solution. Under such conditions IK displays the real time course of potassium conductance (gK) of the membrane. Even though the K+ accumulation had been removed completely, IK still decayed after reaching a peak. This decay is due to gK inactivation, and is well fitted by a dual exponential function, with time constants of approximately 10 ms and of the order of 100 ms. Cytochalasin B applied intracellularly was found to block only one component of gK (with the slow inactivation) in a concentration-dependent manner. At 50 µM cytochalasin B, gK lost the slow inactivation component, thus the decaying gK could be fitted by a single exponential function with time constant of approximately 10 ms. The cytochalasin B-sensitive component had quite different characteristics from the delayed rectifier gK: 1) This component was activated along a single exponential time-course with a time constant of 2 ms at 16.5°C following depolarization and then it decayed slowly toward a steady state. 2) Prepulses of -140 to -60 mV did not alter the time course of the cytochalasin B sensitive gK. Because of the slow activation of the drug-sensitive gK, cytochalasin B did not affect the time course of the action potential. On the other hand, cytochalasin B greatly decreased the steady-state K+ conductance. These results suggest that gK of the squid axon membrane consists of at least two components, i.e. a delayed rectifier K+ channel and a steady-state K+ channel. The cytochalasin B resistant gK may represent the real time- and voltage-dependent characteristics of the delayed rectifier. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
