Cardiovascular regulation and expressions of NO synthase-tyrosine hydroxylase in nucleus tractus solitarius of ovine fetus.
Cardiovascular regulation and expressions of NO synthase-tyrosine hydroxylase in nucleus tractus solitarius of ovine fetus.
复制标题
羊胎孤束核心血管调节及NO合酶-酪氨酸羟化酶的表达。
DOI：
10.1152/ajpheart.00718.2002
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Chao,ConradR
中科院分区：
文献类型：
--
作者：
Ma,Sheng-Xing;Fang,Qun;Morgan,Brian;Ross,MichaelG;Chao,ConradR
本研究的目的是观察近期绵羊第四脑室(4V)注射硝酸甘油(NTG)或一氧化氮合酶(NOS)抑制剂的心血管反应，并确定出生时孤束内侧核(MNTS)去甲肾上腺素能A1神经元是否诱导了神经元NOS(NNOS)。在慢性仪器化胎羊中，4V注射NO供体NTG(1.2nmol)可产生动脉血压下降和中度心率减慢。胎鼠4V注射一氧化氮合酶抑制剂N-硝基-L-精氨酸甲酯(10 Nmnol)可使动脉血压升高。用酪氨酸羟基酶(TH)抗体结合NADPH黄递酶(NADPHd)组织化学方法对胎儿和新生羔羊延髓切片进行观察。新生儿mNTs中NADPHd阳性细胞和含NADPHd反应的TH阳性细胞较胎儿明显增多。结果提示，在出生期间，mNTS去甲肾上腺素能神经元中NADPHd/nNOS表达上调，从而导致胎儿动脉血压的中枢降低。
The purpose of this study was to examine cardiovascular responses to fourth cerebral ventricle (4V) administration of nitroglycerin (NTG) or an inhibitor of nitric oxide (NO) synthase (NOS) in the near-term ovine and to determine whether, during birth, neuronal NOS (nNOS) is induced in noradrenergic A1 neurons in the medial nucleus tractus solitarius (mNTS). In chronically instrumented fetal sheep, 4V injection of NTG (1.2 nmol), an NO donor, produced an arterial blood depressor and a moderate decrease in heart rate. Arterial blood pressure is increased by 4V administration ofNG-nitro-l-arginine methyl ester (10 nmnol), an inhibitor of NOS, in fetuses. Sections of the medulla from fetuses and newborn lambs were examined by using immunolabeling with tyrosine hydroxylase (TH) antibody combined with NADPH diaphorase (NADPHd) histochemistry, a marker of nNOS activity. The NADPHd-positive cells and TH-positive cells containing NADPHd reactivity were significantly increased in the mNTS of newborns compared with the fetuses. The results suggest that during birth, there is upregulation of NADPHd/nNOS in the noradrenergic neurons of mNTS resulting in a centrally mediated reduction of fetal arterial blood pressure.