Frequency dependent sympathetic modulation of vasomotor tone in the anesthetized rat

[摘要] The hypothesis that sympathetic nerve system modulates a specific frequency range of blood pressure fluctuation was tested by electrical stimulation of the medullary sympathetic excitatory sites in anesthetized, paralyzed, vagotomized, cardiac sympathetic blocked, baroreceptor transected and angiotensin II converting enzyme inhibited rats. The frequency tested ranged from 0.02 to 1.7 Hz. For blood pressure fluctuation within this range there was no specific sympathetic reactive zone. Instead, low frequency fluctuation of sympathetic flow produced blood pressure fluctuation of the same frequency. Transfer magnitude of renal sympathetic activity to blood pressure decrease logarithmically with the increase of stimulation frequency. The relationship between the sympathetic spectral power (P-SND, (mu V.S)(2)/Hz) and the blood pressure spectral power (P-BP, mmHg(2)/Mz) was found as P(BP=)10(1.3) x P-SND x 10(-4.7x(frequency)). This transfer function demonstrates that when blood pressure fluctuation is used to estimate the sympathetic activity, it should be frequency weighted. (C) 1997 Elsevier Science Ireland Ltd.

[发布日期] 1997-01-17

[关键词] blood pressure fluctuation;power spectral analysis;rat, sympathetic activity;vasomotor tone