Yoshihiro Fukushima

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Membrane currents through the Ca2+ channel were studied in a hybridoma cell line (MAb-7B) constructed by fusion of S194 myeloma cells and splenic B lymphocytes from the mouse. The whole-cell variation of the patch-electrode voltage-clamp technique was used. When [Ca2+]o = 2.5 mM, [Na+]o = 150 mM and [Na+]i = 155 mM, the current reversed from inward to(More)
1. The kinetics of the anomalous K current produced by blocking cations Na, Cs and Sr were analysed by single channel recording in the tunicate egg cell.2. The open-close kinetics in a single channel with the presence of blocking cation were consistent with the blocking kinetics of the total anomalous K current. The open-close kinetics in a single anomalous(More)
The kinetic properties of a single Na+ channel in the tunicate egg cell membrane were studied by the patch-recording technique. A conventional micropipette filled with a solution of 600 mM NaCl and 1.5 mM MnCl2 was used as the patch electrode. The seal resistance between patch electrode and egg surface was more than 1000 M omega. In the patch recording, the(More)
To identify the functional unit of Ca(2+)-ATPase in the sarcoplasmic reticulum, we assessed Ca(2+)-transport activities occurring on sarcoplasmic reticulum membranes with different combinations of active and inactive Ca(2+)-ATPase molecules. We prepared heterodimers, consisting of a native Ca(2+)-ATPase molecule and a Ca(2+)-ATPase molecule inactivated by(More)
The electrical properties of the cell membrane of clonal cytotoxic T lymphocytes in the mouse were studied by using the whole cell variation of the patch electrode voltage-clamp technique. Outward currents were activated with an exponential time course of several milliseconds time constant when the membrane potential was made more positive than -50 to -40(More)
Electrical properties of the cell membrane were studied in the neoplastic lymphocyte, mouse myeloma cell line S194, by using the whole-cell patch clamp technique. Inward Ca2+ currents due to voltage-gated Ca2+ channels were found. The current, which decayed exponentially after reaching a peak, was first activated at about -50 mV and attained its maximum(More)
Purified (Na,K)ATPase was incorporated into solvent free phospholipid bilayers made on patch-clamp pipettes. In the absence of ATP, the incorporated enzyme acted as an ion-channel which underwent opening and closing (switching) upon application of transmembrane potential gradient of more than 40 mV. The minimum conductance was about 40 pS. It was inhibited(More)
Ca currents of the cell membrane were recorded during a four-day culture period using the whole-cell variation of the patch electrode voltage clamp on a mouse myeloma cell line (S194, non-secreting) and on two mouse hybridoma cell lines (MAb2-1 which secretes immunoglobulin G (IgG) and MAb7B which secretes immunoglobulin M (IgM]. The density of Ca current(More)
To understand the energetics of Ca(2+)-transporting adenosine triphosphatase (Ca(2+)-ATPase), it is important to determine the energy consumption step. To do this, we measured the dissociation of Ca(2+) from Ca(2+)-ATPase into Ca(2+)-loaded vesicles. We observed that 45Ca(2+) added to the outside of the vesicles accumulated in the 40Ca(2+)-loaded vesicles(More)