Atrial natriuretic peptide modulates baroreceptor reflex in spontaneously hypertensive rat

Academic Article

Abstract

  • Our previous studies have suggested that atrial natriuretic peptide in the caudal nucleus tractus solitarii is involved in the centrally mediated regulation of blood pressure in the salt-sensitive spontaneously hypertensive rat (SHR). The current study tested the hypothesis that endogenous atrial natriuretic peptide in the caudal nucleus tractus solitarii participates in baroreceptor reflex control of heart rate in this hypertensive model. Salt-sensitive SHR and control Wistar-Kyoto (WKY) rats maintained on basal (1%) salt intake were studied. Arterial baroreceptor reflex-mediated changes in heart rate were recorded in conscious unrestrained rats during phenylephrine (5-40 μg · kg · min infusion; 30 minutes later, atrial natriuretic peptide (50 ng), monoclonal antibody to atrial natriuretic peptide (0.55 μg), purified mouse immunoglobulin G (0.55 μg), or artificial cerebrospinal fluid vehicle (50 nl) was microinjected into the caudal nucleus tractus solitarii. Phenylephrine infusion was then repeated and mean arterial pressure and heart rate were monitored as before. The slope of the heart rate/mean arterial pressure relation was significantly less (p<0.05) in the salt-sensitive SHR than in the WKY control, indicating that baroreceptor reflex control of heart rate was blunted in this hypertensive model. Microinjection of atrial natriuretic peptide into the caudal nucleus tractus solitarii further blunted (p<0.05) baroreceptor reflex control of heart rate in salt-sensitive SHR but not in WKY rats. In contrast, microinjection of the monoclonal antibody enhanced the sensitivity of baroreceptor reflex control of heart rate in salt-sensitive SHR but not in WKY rats. These data suggest that endogenous atrial natriuretic peptide in the caudal nucleus tractus solitarii modulates baroreceptor reflex control of heart rate in salt-sensitive SHR but not in WKY rats. -1 -1
  • Published In

  • Hypertension  Journal
  • Digital Object Identifier (doi)

    Author List

  • Jin H; Yang RH; Calhoun DA; Wyss JM; Oparil S
  • Start Page

  • 374
  • End Page

  • 379
  • Volume

  • 20
  • Issue

  • 3