Search PubMed⌕ Search

Biomedical subjects

I TASAKI

Publications and source records attributed to I TASAKI.

At least 37 records · Page 2Linked to original sources
PubMed1958

Electric response of glia cells in cat brain.

An experiment is described suggesting that the glia cells in the mammalian cerebral cortex are capable of developing electric responses to direct stimuli. When hyperfine microelectrodes were pushed into the cortex of a cat, slow, reversible potential variations were recorded which resembled the "electric responses" from the glia cells in tissue culture.

Animals↗
PubMed1957

Demonstration of two stable potential states in the squid giant axon under tetraethylammonium chloride.

1. Intracellular injection of tetraethylammonium chloride (TEA) into a giant axon of the squid prolongs the duration of the action potential without changing the resting potential (Fig. 3). The prolongation is sometimes 100-fold or more. 2. The action potential of a giant axon treated with TEA has an initial peak followed by a plateau (Fig. 3). The membrane resistance during the plateau is practically normal (Fig. 4). Near the end of the action potential, there is an apparent increase in the membrane resistance (Fig. 5D and Fig. 6, right). 3. The phenomenon of abolition of action potentials was demonstrated in the squid giant axon treated with TEA (Fig. 7). Following an action potential abolished in its early phase, there is no refractoriness (Fig. 8). 4. By the method of voltage clamp, the voltage-current relation was investigated on normal squid axons as well as on axons treated with TEA (Figs. 9 and 10). 5. The presence of stable states of the membrane was demonstrated by clamping the membrane potential with two voltage steps (Fig. 11). Experimental evidence was presented showing that, in an "unstable" state, the membrane conductance is not uniquely determined by the membrane potential. 6. The effect of low sodium water was investigated in the axon treated with TEA (Fig. 12). 7. The similarity between the action potential of a squid axon under TEA and that of the vertebrate cardiac muscle was stressed. The experimental results were interpreted as supporting the view that there are two stable states in the membrane. Initiation and abolition of an action potential were explained as transitions between the two states.

Action Potentials↗
PubMed1957

Hearing.

Explore the source record for details and available documents.

Hearing↗
PubMed1956

Initiation and abolition of the action potential of a single node of Ranvier.

1. Using single node preparations of the bull frog or the toad, observations were made on the variation of the voltage across the nodal membrane under various experimental conditions. 2. The time constant of the variation in the membrane voltage caused by a long subthreshold rectangular pulse was of the order of 0.1 msec. 3. The action potential was initiated when the potential inside the node was raised stimulating pulses above a threshold level of approximately 15 mv. for a node in normal Ringer; it was greater in a relatively refractory node and in a partially narcotized node. 4. The variation of the membrane voltage caused by long stimulating pulses of subrheobasic strengths was in general proportional to the strength of the applied pulse. A non-linear behavior of the membrane voltage was observed with barely subthreshold stimulating pulses. 5. The early portion of the action potential of a node was not modified by a direct current which was strong enough to produce measurable potential changes (IR drops) across the resting membrane. 6. A strong pulse of inward current applied to the node during activity abolished the portion of the action potential following the pulse in all-or-none manner. 7. There was no refractory period after a response abolished in its early phase. Following a response abolished later, the recovery in the spike height started from the level of the action potential at the time of abolition. 8. Initiation and abolition of action potentials at a single node are interpreted as "transitions" between the two "equilibrium potential levels" at the node.

Action Potentials↗
PubMed1955

The parallelism between the action potential, action current, and membrane resistance at a node of Ranvier.

1. Simultaneous measurements of action potential and resistance and of action current and impedance change have been made at a single node of Ranvier. 2. There is a parallelism between action potential, action current, and resistance change measured at a node of Ranvier. 3. Some implications of these results have been discussed in relation to the corresponding data obtained from the squid giant axon.

Action Potentials↗