Comparison of Cardiorespiratory control Mechanism of Caudal Ventrolateral region of the Medulla in Hypertensive and Normotensive Rats
| Autor: | 邱瑞珍 |
|---|---|
| Rok vydání: | 1997 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 85 Neural factor is one of the main cause of hypertension. It is believed that a enhanced sympathetic activity plays a critical role in the development and the maintenance of essential hypertension. This thesis studied the possible involvement of the parasympathetic system. Stroke-prone spontaneously hypertensive rat (SP) and spontaneously hypertensive rat (SHR), two of the most widely used animal models of essential hypertension, were used as hypertensive rat. Wistar Kyoto rat (WKY) and Wistar rat were used as normotensive controls. Rats were anesthetized with urethane and α-chloralose. Microinjections of glutamate solution (110 pmole) in the ventrolateral region of the medulla were used to probe the cardiac vagal area. Heart rate, blood pressure and diaphragm electromyogram responses were recorded. The maximal responses of heart rate decreases were larger in Wistar than either WKY or SP. With percentile scale, however, there were no differences among the four stains. Hypertensive rats had larger depressor responses. The results support that hypertensive rats has an enhanced sympathetic control in the medulla, whereas their parasympathetic cardioinhibitory control is not changed. In the medulla, heart rate, blood pressure, and respiration points were interrelated. There was no difference in the distribution of all three types of control points. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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