催产素抑制外周刺激诱发的大鼠海马LTP及FOS蛋白表达

 目的 探讨催产素对外周刺激诱发的大鼠海马LTP及Fos蛋白表达的影响。方法 单刺激诱发海马CA1区场电位;强直刺激坐骨神经,诱发海马CA1区长时程增强场电位（LTP）。在强直刺激前于侧脑室内微量注入催产素(Oxytocin,OT)及催产素受体拮抗剂－Atosiban,观察其对LTP的影响。用免疫组化法检测海马Fos蛋白表达。结果 单刺激坐骨神经在海马CA1区诱发出潜伏期固定(171.9±33.1) ms且可重复出现的以正波为主的场电位,平均幅度(25.7±8.4) μV。强直刺激诱导LTP产生,催产素可抑制海马LTP的诱导,但预先注射Atosiban后,海马CA1区仍能出现LTP,但持续时间比对照组短。强直刺激前,海马内c-fos表达为阴性;强直刺激后,表达增强,催产素组表达则较弱,催产素加拮抗剂组也呈强阳性表达。结论 催产素抑制海马LTP的诱导,减弱c-fos的表达,而Atosiban对该效应有一定的抑制作用。提示催产素可能是通过其受体发挥作用的。

Oxytocin inhibits peripheral stimulation-induced LTP and FOS protein expression in hippocampus of rats

Objective To investigate the effects of Oxytocin(OT) on hippocampal long-term potentiation(LTP) and Fos protein expression which induced by peripheral stimulation. Methods Single stimulation pulses were delivered to the left sciatic nerves to evoke the field excitatory postsynaptic potentials (fEPSPs) in the right hippocampal CA1. Tetanic stimulation were used to induce hippocampal LTP. Different groups of rats were given NS, OT, Oxytocin antagonist- Atosiban + OT before tetanic stimulation, into lateral ventricle(LV) respectively. Expression of Fos protein were compared among the groups by histopathological and immunohistochemistry. Results Single stimulation evoked fEPSPs in hippocampal CA1, which average latency was 171.9±33.1ms and average amplitude was 25.7±8.4μV. Tetanic stimulation induced hippocampal LTP and increased the expression of Fos protein. Intracerebroventricular injection of OT inhibited hippocampal LTP and decreased the expression of Fos protein. This effect of OT was blocked by the pretreatment with Atosiban. Conclusions The results suggested that OT may play an inhibitory role in leaning and memory of rats; the effect is mediated by OT receptor.