5-羟色胺、催乳素及皮质醇与血管迷走性晕厥

Serotonin, prolactin and cortisol and vasovagal syncope

血管迷走性晕厥(vasovagal syncope,VVS)的发病机制尚不明确。中枢5-羟色胺(serotonin,5-HT)是一种神经递质,由色氨酸合成,储存于囊泡中。5-HT释放后与突触后膜不同的5-HT受体(serotonin receptor,5-HTR)结合,发挥不同的生物效应。参与心血管调节的中枢5-HTR主要包括5-HT1AR、5-HT2AR、5-HT3R、5-HT7R,其中5-HT1AR激活,降低交感神经反射,增高迷走神经反射,引起血压及(或)心率下降;5-HT3R参与Bezold-Jarisch反射。中枢5-HT可通过与5-HT1A、5-HT1B、5-HT2A/2C等受体结合促进催乳素(prolactin,PRL)释放,同时中枢5-HT与5-HT1A、5-HT1B、5-HT2A/2C、5-HT4受体结合促进皮质醇(cortisol,Cor)释放。因此,PRL及Cor水平与中枢5-HT成正相关性。VVS患者在晕厥或晕厥先兆时PRL及Cor浓度显著增高,提示中枢5-HT可能与VVS发病过程有一定的相关性。

Pathogenesis of vasovagal syncope(VVS)is still unclear. Central serotonin(5-HT)is a neurotransmitter synthesized from tryptophan and stored in vesicles. 5-HT is released into synaptic space by serotoninergic neurons,binding to different serotonin receptors(5-HTRs)on the postsynaptic membrane,exerting their different biological effects. Central5-HTRs involved in cardiovascular regulation mainly include5-HT1 AR,5-HT2 AR,5-HT3 R and 5-HT7 R,in which 5-HT1 AR is activated to reduce sympathetic reflex,increase vagus reflex,and cause the decrease of blood pressure and/or heart rate;5-HT3 R is involved in Bezold-Jarisch reflex. Central 5-HT can promote prolactin(PRL)excretion by binding with 5-HT1 A,5-HT1 B,5-HT2 A/2 C and other receptors,while central 5-HT can promote cortisol(Cor)excretion by binding with 5-HT1 A,5-HT1 B,5-HT2 A/2 C,5-HT4 receptors. Therefore,the levels of PRL and Cor are positively correlated with central 5-HT. In patients with VVS,the level of PRL and Cor increased significantly in syncope or pre-syncope,which suggests that central 5-HT may be related to the pathogenesis of VVS.