Increased renal nerve activity in cardiac failure: arterial vs. cardiac baroreflex impairment.
Cardiac failure is characterized by increased renal sympathetic nerve activity that is associated with an impairment of both arterial and cardiac baroreceptor reflex function. These reflex dysfunctions are in the afferent limb at the level of the peripheral baroreceptors. This study sought to define the relative quantitative magnitude of the defects in arterial and cardiac baroreceptor function in cardiac failure. Renal sympathetic nerve activity was measured in anesthetized normal control rats and rats with cardiac failure (left coronary ligation) during sequential random order sinoaortic denervation and vagotomy to interrupt afferent input from the arterial and cardiac baroreceptors, respectively. Increases in renal sympathetic nerve activity after individual or combined sinoaortic denervation and vagotomy were less (P < 0.05 for both) in cardiac failure than in normal control rats in both order sequences (42 +/- 5 vs. 87 +/- 8%; 44 +/- 5 vs. 108 +/- 7%). In cardiac failure rats, vagotomy produced lesser increases (P < 0.05 for both) in renal sympathetic nerve activity than sinoaortic denervation in both order sequences (10 +/- 4 vs. 32 +/- 5%; 13 +/- 2 vs. 30 +/- 5%). The relative magnitude of impaired cardiac baroreceptor reflex function that is associated with the increased renal sympathetic nerve activity of cardiac failure is greater than that of impaired arterial baroreceptor reflex function.
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
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DiBona
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Sawin
D000704:Analysis of Variance; D000818:Animals; D001158:Arteries / Q000503:physiopathology; D017704:Baroreflex; D001794:Blood Pressure; D003714:Denervation; D003971:Diastole; D006321:Heart / Q000503:physiopathology; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate; D007668:Kidney / Q000294:innervation*; D008297:Male; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012849:Sinoatrial Node / Q000502:physiology / Q000503:physiopathology; D013997:Time Factors; D014628:Vagotomy; D016277:Ventricular Function, Left; D017725:Ventricular Pressure