Atrial natriuretic peptide inhibits sympathetic outflow in NaCl-sensitive spontaneously hypertensive rats.
The current study tested the hypothesis that circulating atrial natriuretic peptide (ANP) inhibits sympathetic outflow, as reflected in lumbar sympathetic nerve activity (LSNA), in NaCl-sensitive spontaneously hypertensive rats (SHR-S) and that this effect is exaggerated by high NaCl feeding. NaCl-resistant SHR (SHR-R) and Wistar-Kyoto (WKY) rats maintained on basal and high-NaCl diets were used as controls. Intravenous administration of ANP to conscious, freely moving rats with intact baroreflexes decreased blood pressure and LSNA in SHR-S, SHR-R and WKY rats maintained on basal or high-NaCl diets for 2-3 weeks. The depressor response to intravenous ANP was greater in 8% NaCl-fed SHR-S than in any other group; the LSNA response was greater in SHR-S on either diet than in any other group. Intracerebroventricular administration of ANP evoked small, transient sympatholytic responses in SHR-S on both diets and minimal responses in SHR-R and WKY rats; these responses could not be attributed to leakage of ANP into the peripheral circulation. Thus, circulating ANP has a sympatholytic effect in SHR-S that is not amplified by high-NaCl feeding and can be only partially accounted for by a central action.
Oparil
S
S
Department of Medicine, University of Alabama at Birmingham 35294.
Chen
Y F
YF
Wang
R P
RP
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006973:Hypertension / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012982:Sodium, Dietary / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*
D012982:Sodium, Dietary; D009320:Atrial Natriuretic Factor