Khaziev E F, Samigullin D V, Tsentsevitsky A N, Bukharaeva E A, Nikolsky E E
Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 30, Kazan, 420111, Russia.
Institute of Fundamental Biology and Medicine, Kazan Federal University, Open Lab "Neuropharmacology", Kremlevskaya Str. 18, Kazan 420008, Russia.
Acta Naturae. 2018 Apr-Jun;10(2):93-96.
At neuromuscular junctions, ATP inhibits both the evoked and spontaneous acetylcholine release and inward calcium current operating via presynaptic P2Y receptors. It was shown in the experiments with the frog neuromuscular synapse using specific calcium-sensitive dye Oregon Green Bapta 1 that exogenous ATP reduces the amplitude of calcium transient, which reflects the changes in the entry of calcium ions in response to the nerve pulse. The depressing effect of ATP on the transient was prevented by suramin, the blocker of P2 receptors. Nitrendipine, a specific blocker of L-type calcium channels, decreased the calcium transient amplitude and significantly attenuated the effect of ATP on the calcium signal. Contrariwise, the preliminary application of ATP to the neuromuscular junction completely eliminated the depressing effect of nitrendipine on the calcium response. The obtained data suggest that an essential component in the inhibitory action of ATP on the calcium transient amplitude is provided by reduction of the entry of calcium ions into a frog nerve ending via L-type voltage-gated calcium channels.
在神经肌肉接头处，ATP通过突触前P2Y受体抑制诱发的和自发的乙酰胆碱释放以及内向钙电流。在使用特定钙敏染料俄勒冈绿Bapta 1对青蛙神经肌肉突触进行的实验中表明，外源性ATP会降低钙瞬变的幅度，这反映了钙离子响应神经脉冲进入时的变化。P2受体阻滞剂苏拉明可阻止ATP对瞬变的抑制作用。L型钙通道的特异性阻滞剂尼群地平降低了钙瞬变幅度，并显著减弱了ATP对钙信号的影响。相反，预先将ATP应用于神经肌肉接头可完全消除尼群地平对钙反应的抑制作用。所获得的数据表明，ATP对钙瞬变幅度的抑制作用的一个重要组成部分是通过L型电压门控钙通道减少钙离子进入青蛙神经末梢。
