家兔延髓最后区对心血管活动的调节

THE REGULATION OF AREA POSTREMA IN CARDIOVASCULAR FUNCTION IN RABBIT

目的:探讨家兔延髓最后区(AP)对心血管活动的调节作用及机制。方法:以10%脲酯和1%氯醛糖混合静脉麻醉家兔,人工呼吸。给AP不同频率(10 Hz^80 Hz)电刺激,观察平均动脉压(MAP)和心率(HR)的变化;及损毁CVLM或RVLM后AP兴奋的心血管效应改变。结果:电刺激AP,低频(10 Hz2、0 Hz)刺激使MAP下降、HR减慢;高频(60 Hz8、0 Hz)刺激使MAP升高,HR减慢。损毁CVLM后刺激AP,20 Hz刺激引起的降压作用消失(P<0.01),80 Hz刺激效应同前(P>0.05)。损毁RVLM后刺激AP,20 Hz8、0 Hz刺激引起的降压、升压作用均消失(P<0.01)。结论:低频电刺激AP,引起降压和心率减慢,高频电刺激AP引起升压和心率减慢;前者可能与兴奋CVLM有关,不同电刺激引起的心血管效应均通过RVLM介导。

Aim： To determine the role of area postrema（AP） of rabbit in the regulation of cardiovascular function. Methods： The rabbits were anesthetized with intravenous injection of 10% urethane and 1% chloralose, and were artificially ventilated. The changes of mean arterial pressure（MAP） and heart rate（HR） were observed when AP was electrically stimulated with different frequency （ 10 Hz～80 Hz） and after chemical lesion of CVLM or RVLM, respectively. Results： Electrical stimulation of AP with low frequency （10 Hz, 20 Hz） decreased MAP and HR. Stimulation with high frequency（60 Hz, 80 Hz） increased MAP but decreased HR. The changes in MAP and HR were significantly lower（ P〈 0.01 ） after CVLM was destroyed when electrical stimulation of AP with 20 Hz, and both changes of MAP and HR were disappeared（ P〈 0.01） after RVLM was destroyed when electrical stimulation with 20 and 80 Hz. Conclusion： Electrical stimulation of AP with low frequency decreases MAP and HR, stimulation with high frequency induces an increase in MAP and deceases in HR. The former is probably related to excitation of CVLM, the cardiovascular effects induced by different frequency of electrical stimulation are all resulted from the activation of RVLM.