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Hirofumi Kitagawa

Publications and source records attributed to Hirofumi Kitagawa.

3 recordsLinked to original sources
PubMed2004

NMDA receptor-dependent long-term potentiation is dependent on low-voltage-activated calcium currents in the sensorimotor cortex of cats.

The role of low-voltage-activated (LVA) calcium channels in the expression of long-term potentiation (LTP) was examined by intracellular recording in slices from cat agranular cortex. In the normal solution, LTP was induced, and the potentiation of low-threshold rebound potential was evoked by negative current injection. In the cells, in which resting membrane potential was depolarized, the incidence of LTP was very low. LTP was blocked completely in the presence of NMDA receptor antagonist or 50-100 microM nickel. It was suggested that LVA calcium channels function downstream of NMDA receptor-dependent signaling.

2-Amino-5-phosphonovalerate↗
PubMed2002

Properties of voltage dependent potassium currents in acutely isolated rat oculomotor neurons.

Voltage-dependent potassium currents in oculomotor neurons (OMNs) were studied with whole-cell patch clamp recordings. Fast inactivating outward currents (I(fast)) had half activation voltage (Vh) of -37.1 mV with slope factor (Vc) of 10.9 mV. I(fast) had half inactivation voltage (Vh) of -66.5 mV and Vc of 11.4 mV. I(fast) decayed with a time constant(tau) of 5.1 ms at +10 mV. I(fast) were sensitive to 4-aminopyridine, showing 50% inhibitory concentration (IC(50)) of 0.97 mM. Slowly inactivating outward currents (I(slow)) had two components. The low-concentration-TEA-sensitive currents had Vh of -3.7 mV with Vc of 9.7 mV in activation and had Vh of -54.7 mV with Vc of 23.8 mV in inactivation. The persistent currents had Vh of 7.4 mV and Vc of 11.8 mV in activation and Vh of -54.4 mV and Vc of 21.2 mV in inactivation. Decay of I(slow) (+10 mV) followed a double exponential time course (tau 215, 1165.6 ms). Low-concentration-TEA-sensitive currents were blocked completely by tetraethylammonium (TEA) of 3 mM with an IC(50) of 1.52 mM. Higher concentrations (3-20 mM) of TEA blocked the persistent currents, with an IC(50) of 6.9 mM.

Action Potentials↗