Crepel F, Daniel H, Hemart N, Jaillard D
Laboratoire de Neurobiologie et Neuropharmacologie du Développement, URA CNRS 1121, Université Paris-Sud, Orsay, France.
Exp Brain Res. 1991;86(2):402-6. doi: 10.1007/BF00228964.
The effects of trans-1-amino-cyclopentyl-1,3-dicarboxylate (trans-ACPD) and of DL-2-amino-3-phosphonopropionic acid (AP3), i.e. selective agonist and antagonist of metabotropic quisqualate receptors respectively, on parallel fibre (PF)-mediated EPSPs of Purkinje cells (PCs) were studied in an in vitro slice preparation. Bath application of 500 microM trans-ACPD in conjunction with PF stimulation at 0.2 or 1 Hz depending on the cell always induced a marked depression of PF-mediated EPSPs, which was fully reversible in most cases after wash-out of this compound. Trans-ACPD also often induced a transient depolarization of PCs which induced calcium spike firing in these cells and which again no longer persisted after wash-out of trans-ACPD. Even in cells which were depolarized by trans-ACPD, the decrease in amplitude of PF-mediated EPSPs started before the appearance of calcium spikes, lasted longer than the transient depolarizing effect of trans-ACPD, and was accompanied by no variation in input resistance of the cells when they were manually clamped at their initial resting potential. Bath application of 600 microM DL-AP3 had no effect on PF-mediated EPSPs or the bioelectrical activities of PCs. Moreover, it did not prevent the effects of trans-ACPD mentioned before. The present results are not consistent with the view that coactivation of ionotropic and metabotropic quisqualate receptors of PCs is sufficient to induce a long-term depression of PF-mediated EPSPs.
在体外脑片制备中，研究了反式-1-氨基环戊基-1,3-二羧酸（反式-ACPD）和DL-2-氨基-3-膦酰丙酸（AP3）（分别为代谢型喹啉酸受体的选择性激动剂和拮抗剂）对浦肯野细胞（PCs）平行纤维（PF）介导的兴奋性突触后电位（EPSPs）的影响。根据细胞情况，在浴槽中应用500微摩尔的反式-ACPD并结合0.2或1赫兹的PF刺激，总能诱导PF介导的EPSPs明显抑制，在大多数情况下，洗脱该化合物后这种抑制是完全可逆的。反式-ACPD还经常诱导PCs短暂去极化，导致这些细胞产生钙峰放电，在洗脱反式-ACPD后这种情况也不再持续。即使在被反式-ACPD去极化的细胞中，PF介导的EPSPs幅度下降也在钙峰出现之前开始，持续时间比反式-ACPD的短暂去极化作用更长，并且当手动钳制细胞使其处于初始静息电位时，细胞的输入电阻没有变化。在浴槽中应用600微摩尔的DL-AP3对PF介导的EPSPs或PCs的生物电活动没有影响。此外，它不能阻止之前提到的反式-ACPD的作用。目前的结果与以下观点不一致，即PCs离子型和代谢型喹啉酸受体的共同激活足以诱导PF介导的EPSPs的长期抑制。
