| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
To investigate the effects of neuromodulators on synaptic transmission and cell excitability, we performed in vitro electrophysiological study using slice patch-clamp recording.
Summary of this research results are described as follow.
1.The effects of dopamine on GABAergic transmission in the medial prefrontal cortex.
Dopamine (20 μM) reduced the frequency of miniature GABAergic IPSCs by 〜40%, and this reduction was observed in all the cells examined. Depending on the type of layer V pyramidal neuron, however, the effects of dopamine on the amplitude of miniature IPSCs are different with a decrease by 36.4±6.8% in four, cells and an increase by 40.3±7.8% in five cells.
2.The effects of dopamine on resting membrane potential of cortical cells in the medial prefrontal cortex.
Dopamine (20 μM) often depolarized GABAergic cells to continuously discharge spikes in layer V of this cortical region. The frequency of depolarization differed significantly, depending upon the cell type : Fast-spiking cells 18.8% (3/16), Low-threshold spiking cells 21.1% (4/19) and Regular-spiking cells 34.8% (8/23).
On the other hand, dopamine (20 μM) did not affect membrane potential of the pyramidal cells in layer V at all.
3.The effects of dopamine, noradrenaline, serotonin and carbachol on afterhyperpolarization of layer V pyramidal cells.
Dopamine did not have effect on either afterhyperpolarization or the membrane currents underlying the hyperpolarization, whereas carbachol, noradrenaline and serotonin reduced both afterhyperpolarization and the membrane currents. These reductions in afterhyperpolarization and the currents underlying the afterhyperpolarization accompanied the increase in frequency of pyramidal cells during depolarizing current injection.
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