抄録
To elucidate functional properties of human astrocytoma cell lines, U-251MG, U-87MG, and KINGS-1, we examined the expression of neurotransmitter receptors with Ca2+ imaging. Those cells were loaded with Ca2+ sensitive dye (fura-2 AM), and subjected to measurement of the Ca2+-dependent fluorescence changes using a specific imaging device. The cells which showed the increase in [Ca2+]i during the administration of a neurotransmitter were classfied as positive. We tested the effects of amino acid (glutamate), catecholamine (noradrenaline), autacoid (histamine), and others (ATP, acetylcholine) on each cell line. The astrocytoma cells showed positive responses during the administration of histamine, acetylcholine, noradrenaline, and ATP. The amplitude of Ca2+ response was dose-dependent (10 nM–1 mM), and significantly reduced by each specific antagonist. Surprisingly, Ca2+ measurement indicated that those cells showed a negative sensitivity to glutamate (100 μM), which had been reported to be an important mediator between glial cells and neuronal cells. Those results suggest that the loss of glutamate receptor is involved in an initial step of the functional disorder of communication between astrocytes and neurons in the human brain. [J Physiol Sci. 2008;58 Suppl:S82]
