Reiner Eckert

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Under depolarizing voltage clamp of Paramecium an inward calcium current developed and subsequently relaxed within 10 milliseconds. The relaxation was substantially slowed when most of the extracellular calcium was replaced by either strontium or barium. Evidence is presented that the relaxation is not accounted for by a drop in electromotive force acting(More)
'Wash-out' and inactivation of the Ca current were examined in dialysed, voltage-clamped neurones of Helix aspersa under conditions that isolate the Ca current virtually free of other currents. EGTA or other internal Ca2+ chelators were routinely omitted from the dialysate. The time-dependent loss, or wash-out, of Ca current was slowed by addition to the(More)
Two classes of calcium channels were activated by membrane depolarization in cell-free membrane patches from GH3 cells, an electrically excitable cell line derived from a mammalian pituitary tumor. One class had a conductance of approximately 10 pS in 90 mM barium, had a threshold of activation near -40 mV, and was inactivated rapidly at holding potentials(More)
Ca currents flowing during voltage-clamp depolarizations were examined in axotomized Aplysia neurones under conditions that virtually eliminated other currents. Moderate to large currents exhibited a two-component time course of relaxation that can be approximated reasonably well by the sum of two exponentials. The rapid phase (tau 1 approximately equal to(More)
1. An intracellular voltage clamp in conjunction with a patch pipette utilizing feed-back to monitor local current from the soma membrane were used to analyse transient and stationary currents in bursting pacemaker neurones in Helix pomatia and H. levantina. 2. A weak, net inward current flows during small (less than or equal 20 mV) depolarizations. This(More)
Computer-assisted modeling of calcium influx through voltage-activated membrane channels predicted that buffer-limited elevation of cytoplasmic free calcium ion concentration occurs within microscopic hemispherical "domains" centered upon the active Ca channels. With increasing depolarization, the number of activated channels, and hence the number of Ca(More)