摘要目的 探讨5-羟色胺2A(5-HT2A)受体对新生大鼠延髓脑片吸气神经元放电的调制作用.方法 制作新生大鼠离体延髓脑片标本,给予灌流恒温改良Kreb's液(MKS),使用内含银一氯化银电极的吸附电极吸附舌下神经根,稳定记录舌下神经根呼吸相关节律性放电活动(RRDA)后,使用微电极以细胞外记录方式在面神经后核内侧区同步记录吸气神经元放电.同步记录舌下神经根RRDA和吸气神经元放电后,用含40μmol/L 5-HT2A受体特异激动剂2,5-二甲氧基-4-碘苯基丙烷-2胺盐酸盐(DOI)的MKS充分灌流延髓脑片,记录吸气神经元放电活动变化,冲洗至RRDA和吸气神经元放电基本恢复,用含5-HT2A受体特异拮抗剂酮舍林的MKS灌流脑片,记录吸气神经元放电活动变化.结果 使用DOI激活5-HT2A受体后,吸气神经元放电时程(TI)为(0.86±0.07)s,呼气时程(TE)为(10.78±1.06)s,呼吸周期(RC)为(11.79±1.64)s,吸气神经元放电积分幅度(IA)为(357.98±37.21)(μV·s),放电峰频率(PF)为(37.83±3.66)Hz,对照组分别为(0.68±0.06)s、(13.89±2.14)s、(14.77±1.92)s、(273.57±24.39)(μV·s)和(29.92±4.50)Hz, DOI组与对照组比较均有显著差异(Pa＜0.01).对吸气神经元放电有兴奋作用.应用酮舍林后,缩短TI为(0.55±0.07)s,延长TE为(18.43±3.28)s, RC为(20.17±2.91)s, IA减为(214.37±33.52)(μV·s),PF为(22.17±3.92)Hz,与对照组和DOI组比较均有显著差异(Pa＜0.01).对吸气神经元放电有抑制作用.结论 5-HT2A受体参与调节新生大鼠延髓脑片吸气神经元放电活动.

abstractsObjective To explore the modulatory effect of 5-HT2A receptors on the discharge activities of inspiratory neurons in medial region of nucleus retrofacialis of neonatal rats. Methods Experiments were performed in vitro brainstem slice preparations from neonatal rats. These preparations included the medial region of nucleus retrofacialis with the hypoglossal nerve rootlets retained. The rhythmic discharges of the inspiratory neurons and activities of the hypoglossal nerve rootlets were simultaneously recorded by using microelectrodes and suction electrodes, respectively. Roles of 5-HT2A receptors in modulation of the discharge activities of inspiratory neurons were investigated by administration of the 5-HT2A receptor agonist 1-(2,5-dimethoxy-4-iodopbenyl)-2-aminopropane (DOI), and its specific antagonist ketanserine dissolved in modified Kreb's solution for perfused slices. Results In DOI group, the inspiratory time (TI) was (0.864±0.07)s, expiratory time (TE) was (10.78±1.06)s, respiratory cycle (RC) was (11.79±1.64)s, integral amplitude (IA) was (357.98±37.21)(μV·s) and the peak discharge frequency (PF) was (37.83±3.66)Hz. In control group, they were (0.68±0.06)s, (13.89±2.14)s, (14.77±1.92)s, (273.57±24.39)(μV·s), and (29.92±4.50)Hz, there were significant differences between the 2 groups (Pa<0.01). In ketanserine group, TI was (0.55±0.07)s, TE and RC were (18.43±3.28)s and (20.17+2.91)s respectively, IA and PF were (214.37±33.52)(μV·s) and (22.17±3.92)Hz, there were significant differences between ketanserine group and DOI, control group (Pa<0.01). Conclusion 5-HT2A receptors take part in modulate the discharge activities of inspiratory neurons in neonatal rat brainstem slices.