目的以长时程增强(LTP)为指标,研究调心方(TXR)活性部位A(TXR-A)对皮质酮抑制大鼠海马脑片LTP作用的影响。方法将脑片分为正常对照组、皮质酮组、皮质酮+TXR组、皮质酮+不同浓度TXR-A组,记录前脑片用含药人工脑脊液(ACSF)孵育1h,记录时用相同ACSF灌流。采用细胞外微电极记录技术,记录大鼠海马脑片CA1区诱发群峰电位(PS),然后施以100Hz、100个脉冲的强直刺激HFS诱发LTP。结果与正常脑脊液组相比,皮质酮(2μmol/L)孵育海马脑片1.5h以上,强直刺激后PS增幅显著降低,提示皮质酮对海马LTP具有抑制作用。用不同浓度的TXR-A+皮质酮孵育脑片1.5h以上,强直刺激后高浓度TXR-A组的PS平均幅度显著提高,且作用优于TXR。提示TXR-A可以对抗皮质酮对LTP的抑制。结论该活性部位可能是发挥TXR改善皮质酮抑制大鼠海马CA1区诱发LTP作用的主要成分之一,拮抗皮质酮对LTP的抑制是其益智作用的机制之一。

Objective To investigate the effect of active fraction A (TXR-A) extracted from Tiaoxin Recipe (TXR) on inhibition of corticosterone on long-term potentiation (LTP) induced by high frequency stimulation (HFS) in rat hippocampal slices. Methods The slices were divided into control, corticosterone, corticosterone+TXR, and corticosterone+different concentration of TXR-A groups, then were incubated with artificial cerebrospinal fluid (ACSF) added by drugs for 1 h before recording and were perfused with the same ACSF during recording. Population spike (PS) was recorded from stratum pyramidale of area CA1 using extracellular recording following stimulation of Schaffer collaterals in rat hippocampal slices. Then a 100 Hz, 100 pulses HFS was used to induce LTP. Results PS amplitude was decreased significantly vs that in the control group, when the slices were pre-incubated in ACSF added by corticosterone (2 μmol/L) over 1.5 h, meaning that LTP was inhibited by corticosterone. However, PS amplitude of the slices pre-incubated in ACSF added by corticosterone (2 μmol/L) and high concentration TXR-A was increased significantly vs that of corticosterone pre-treating slices, meaning that high concentration TXR-A enhanced LTP inhibited by corticosterone. Furthermore, increased LTP amplitude in high concentration TXR-A was much more than that in TXR. Conclusion TXR-A is one of main TXR active ingredients which facilitate LTP inhibited by corticosterone in area CA1 of rat hippocampal slices. The antagonist (effect) on corticosterone inhibition on LTP is one of the mechanisms to benefit the intelligence.