SUPRABULBAR EFFECTS OF SINOAORTIC DENERVATION

去窦弓神经（SAD）大鼠具有轻度高血压和不稳定性， 与身体运动相关的动脉压， 加压素 最近的研究表明，酪氨酸羟化酶（TH） 活动和多巴胺（DA）浓度降低，在尾状核 SAD大鼠中脑核TH活性降低 黑质和视上核（SON）。 由于黑质纹状体系统是一个 躯体运动神经整合的主要部位，并且由于中枢活性DA 激动剂在某些形式下具有降低血压的作用， 高血压，这一假设将被测试，减少DA代谢， 黑质纹状体引起了与身体运动有关的压力 SAD大鼠的不稳定性，并有助于其轻度高血压。 DA激动剂的显微注射将被制成黑质纹状体， 自由活动的SAD和假手术对照组大鼠， 和心率都被连续记录下来 联机DEC计算机 将生成频率间隔直方图、平均值和标准差 压力和心率的值。 损伤的血流动力学效应 还将评价正常大鼠的黑质纹状体区。 另一 有待检验的假设是， 下丘脑中的儿茶酚胺抑制SAD患者的血管加压素分泌 大鼠 在体内和体外TH活性，释放和周转 测量SON和室旁核中的儿茶酚胺。 的 黑质纹状体和黑质纹状体中生化变化的发作时间和持续时间 将研究下丘脑区域。 尾状核的变化也开始 将通过体内伏安法进行评估，在试点研究中， DA通过去窦弓神经释放。 所有生化检测将 灵敏、特异和放射性同位素。 最后，荧光 探针将被用来寻找脑干之间投射的证据。 与心血管调节和黑质相关的区域。

The sinoaortic denervated (SAD) rat has mild hypertension and labile arterial pressure associated with body movements and haselevated plasma vasopressin. Recent investigations revealed that tyrosine hydroxylase (TH) activity and dopamine (DA) concentration were reduced in the caudate nucleus of SAD rats and that TH activity was also reduced in substantia nigra and supraoptic nucleus (SON). Since the nigrostriatal system is a major site of somatomotor neural integration and since centrally active DA agonists have a blood pressure lowering effect in some forms of hypertension, the hypothesis will be tested that reduced DA metabolism in the nigrostriatum causes the characteristic body movement- related pressure lability of SAD rats and contributes to their mild hypertension. Microinjections of DA agonists will be made into the nigrostriatum of freely moving SAD and sham-operated control rats whose arterial pressure and heart rate are being continuously recorded. An on-line DEC computer will generate frequency-interval histograms, mean and standard deviation values of pressure and heart rate. Hemodynamic effects of lesioning nigrostriatal region of normal rats will also be evaluated. Another hypothesis to be tested is that reduced synthesis and release of catecholamines in the hypothalamus disinhibits vasopressin secretion in SAD rats. In vivo and in vitro TH activity, release and turnover of catecholamines in SON and paraventricular nucleus will be measured. The time of onset and duration of biochemical changes in both nigrostriatal and hypothalamic regions will be studied. Onset of changes in caudate also will be evaluated by in vivo voltammetry which, in pilot studies, indicated DA was released by sinoaortic denervation. All biochemical assays will be sensitive, specific and radioisotopic. Finally immunohistofluorescent probes will be used to look for evidence of projections between brain stem areas associated with cardiovascular regulation and the substantia nigra.