Effect of Tetrandrine on Arterial Baroreflex Function in Sinoaortic Denervated Rats
|School||Taishan Medical College|
|Keywords||Tetrandrine Nifedipine Sinoaortic denervation Blood pressure Blood pressure variability Hypertension Arterial baroreflex Heart rate variability Angiotensin Ⅱ Organ damage|
Objective: patients with hypertension or hypertensive animals is often associated with blood pressure elevated volatility (BPV) and arterial baroreflex (ABR) function defects. The BPV higher end-organ damage that can lead to cardiac hypertrophy, vascular remodeling and renal lesions. ABR function is often measured by the size of the baroreflex sensitivity (BRS). The ABR function reduce BPV elevated. To surgical methods to remove the aortic arch and carotid sinus receptors and / or afferent nerve, called sinoaortic nerve (SAD). SAD rats have elevated blood pressure, volatility, and the 24-hour average blood pressure is essentially the same features. The heart rate variability (HRV) can fully reflect cardiac autonomic function. HRV research, contribute to the understanding of the pressure to feel the formation mechanism of the regulation and blood pressure fluctuations. The main method for the treatment of hypertension is to rely on anti-hypertensive drugs, which requires anti-hypertensive drugs can lower blood pressure, able to combine reduced the BPV to achieve the purpose of protecting target organs. The experimental observation has antihypertensive effect of active ingredients of traditional Chinese medicine tetrandrine (Tet, the tetrandrine prime) administered intravenously the SAD rats BPV, BRS and HRV impact of freely moving state. MATERIALS AND METHODS: Male SD rats ,230-250g, 50, all of the rows to sinoaortic nerve surgery made from blood pressure fluctuations in a rat model. Success through the verification model of blood pressure monitoring and target organ pathology observed. Rats freely moving awake state, the use of computerized freely moving rats hemodynamic monitoring techniques, observation of tetrandrine the the the sinoaortic nerves rat BPV, BRS and HRV impact. Which the tetrandrine 15mg/kg group, 30 mg / kg group, 60mg/kg groups of 10; nifedipine 5mg/kg group 10; 10 saline group, all drugs by intravenous constant speed bolus to drugs. 14 hours after the end of the blood pressure recorded from four hours before the administration began to administration. 2 hours after the administration of pre-recorded after 12 hours as of late. Before and after administration compared using a paired t-test, the two groups were compared using two-sample t-test, SNK test was used to compare between any two groups BRS calculated using linear regression analysis. P lt; 0.05 as the significance level. Results: 1. Tetrandrine can reduce SAD state of freely moving rats blood pressure, cardiac cycle. Nifedipine (5mg/kg) was significantly buck while filling the heart rate accelerated. Tetrandrine administered intravenously significantly reduce the BPV in SAD rats, the effect lasted for at least 14 hours and its low dose was not significantly reduce systolic blood pressure, but can significantly reduce the BPV. Nifedipine only within about 2 hours to stabilize the BPV, after gradually increased. 3. 2 hours after the administration of tetrandrine measured BRS enhanced with dose trend may not fully reflect the changing trends of rats the BPV With dose administration. 2 hours after the administration of nifedipine measured BRS reduced, the values ??measured after 14 hours than after administration of 2 hours measured value increases. Conclusion: After intravenous administration of tetrandrine significantly reduce BPV in SAD rats, the effect lasted for at least 14 hours. When you the low dose tetrandrine reduce BPV, systolic blood pressure did not change. Nifedipine administered within about two hours after the stable BPV, after gradually increased. The 2 Tetrandrine improve SAD rats BRS. The effects of high-dose group over the last 14 hours. The Nifedipine so BRS significantly lower after rise gradually. Tetrandrine administration to sinus bow nerves rats without reflex tachycardia. 4 tetrandrine, nifedipine the SAD rats HRV no significant impact.