Albarran F A, Roa J P, Navarrete R, Castillo R, Nualart F, Aguayo L G
Laboratory of Neurophysiology, Department of Physiology, P.O. Box 160-C, University of Concepcion, Chile.
Brain Res. 2001 May 25;902(1):1-10. doi: 10.1016/s0006-8993(01)02255-7.
We investigated whether the effect of phorbol-12-myristate-13-acetate (PMA) was altered by a kinase inhibitor and by down-regulation of protein kinase C (PKC) in order to determine if glycine receptors in mouse spinal neurons, unlike those in hippocampal and trigeminal neurons, can be inhibited by PKC. To examine the above, electrophysiological and immunofluorescence studies were carried out in mouse spinal neurons kept in culture for up to 3 weeks. The inhibition of the glycine activated current by PMA (1 microM) increased from 12+/-3% during week 1 to 27+/-6% during week 3. The effect of PMA was completely blocked by the PKC selective inhibitor RO 31-8220 (1 microM). After culturing the cells with 1 microM PMA for 24 h, the inhibitory effect of acute application of PMA disappeared altogether, suggesting that the effect of PMA was via PKC. Immunofluorescence studies showed that a short stimulation with PMA translocated the enzyme to the periphery whereas longer term stimulation (24 h) down regulated the PKC signal. These results indicate that activation of PKC by PMA inhibits the glycine receptor in cultured spinal neurons and that its sensitivity changes during neuronal development.
我们研究了佛波醇-12-肉豆蔻酸酯-13-乙酸酯（PMA）的作用是否会因激酶抑制剂和蛋白激酶C（PKC）的下调而改变，以确定小鼠脊髓神经元中的甘氨酸受体是否与海马体和三叉神经元中的不同，能够被PKC抑制。为了研究上述问题，我们对培养长达3周的小鼠脊髓神经元进行了电生理和免疫荧光研究。PMA（1微摩尔）对甘氨酸激活电流的抑制作用从第1周的12±3%增加到第3周的27±6%。PKC选择性抑制剂RO 31-8220（1微摩尔）完全阻断了PMA的作用。在用1微摩尔PMA培养细胞24小时后，急性应用PMA的抑制作用完全消失，这表明PMA的作用是通过PKC实现的。免疫荧光研究表明，短暂用PMA刺激会使该酶转移到细胞周边，而长期刺激（24小时）则会下调PKC信号。这些结果表明，PMA激活PKC会抑制培养的脊髓神经元中的甘氨酸受体，并且其敏感性在神经元发育过程中会发生变化。
