Data from: Substance P signalling in primary motor cortex facilitates motor learning in rats

Among the genes that are up-regulated in response to a reaching training in rats, Tachykinin 1 (Tac1) - a gene that encodes the neuropeptide Substance P (Sub P) - shows an especially strong expression. Using Real-Time RT-PCR, a detailed time-course of Tac1 expression could be defined: a significant peak occurs 7 hours after training ended at the first and second training session, whereas no up-regulation could be detected at a later time-point (sixth training session). To assess the physiological role of Sub P during movement acquisition, microinjections into the primary motor cortex (M1) contralateral to the trained paw were performed. When Sub P was injected before the first three sessions of a reaching training, effectiveness of motor learning became significantly increased. Injections at a time-point when rats already knew the task (i.e. training session ten and eleven) had no effect on reaching performance. Sub P injections did not influence the improvement of performance within a single training session, but retention of performance between sessions became strengthened at a very early stage (i.e. between baseline-training and first training session). Thus, Sub P facilitates motor learning in the very early phase of skill acquisition by supporting memory consolidation. In line with these findings, learning related expression of the precursor Tac1 occurs at early but not at later time-points during reaching training.

在大鼠接受伸手训练后上调表达的基因中，编码神经肽P物质（Substance P，Sub P）的速激肽1（Tac1）展现出尤为显著的表达水平。本研究采用实时荧光定量逆转录聚合酶链反应（Real-Time RT-PCR），明确了Tac1表达的完整时间进程：首次与第二次训练结束后7小时，Tac1表达出现显著峰值，而在后续时间点（第六次训练）则未检测到表达上调。为探究P物质在运动习得过程中的生理功能，研究人员向受训练爪对侧的初级运动皮层（M1）实施了显微注射操作。若在首次至第三次伸手训练前注射P物质，大鼠的运动学习效率会显著提升；而当大鼠已掌握该任务时（即第十与第十一次训练阶段）进行注射，则对伸手表现无显著影响。P物质注射不会影响单次训练内的表现提升，但可在极早期阶段（即基线训练与首次训练之间）强化训练间的表现留存能力。由此可见，P物质可通过支持记忆巩固，在技能习得的极早期阶段促进运动学习。与上述研究结果一致，前体Tac1的学习相关表达仅出现在伸手训练的早期阶段，而非后续时间点。