Rapid baroreceptor resetting is unaltered by chronic hypertension in rats

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Abstract

This study compares rapid baroreceptor resetting in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Single-fiber baroreceptor activity and aortic diameter were measured in in vitro preparations. Baroreceptor pressure threshold (P(th)) and suprathreshold pressure sensitivity were measured during periods after various levels of conditioning mean arterial pressure (cMAP). The ability of a baroreceptor to reset was expressed as the resetting ratio (ΔP(th)/ΔcMAP). Rapid resetting was successfully characterized in 30 baroreceptors (18 SHR and 12 WKY). SHR blood pressures were higher, and aortic distensibility was lower than in WKY. SHR baroreceptors showed signs of chronic resetting, i.e., elevated P(th) (105.4 vs. 88.5 mmHg, SHR and WKY, respectively) and decreased suprathreshold sensitivity (0.92 vs. 1.42 spikes · s-1 · mmHg-1, SHR and WKY, respectively), but their resetting ratios were similar to WKY (0.260 and 0.237, SHR and WKY, respectively). Characterization of rapid resetting of more than one baroreceptor from single animals reveals that the resetting ratio can vary by > 50% within animals. During simultaneous discharge-diameter recordings, the strain threshold was better correlated to cMAP than P(th). We conclude that the ability of baroreceptors to rapidly reset is unaltered by chronic hypertension or chronic baroreceptor resetting, and we hypothesize that rapid resetting is probably a result of an intrinsic neural property rather than vessel mechanics.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume256
Issue number4
StatePublished - 1989
Externally publishedYes

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Pressoreceptors
Inbred WKY Rats
Inbred SHR Rats
Hypertension
Arterial Pressure
Pressure
Mechanics

ASJC Scopus subject areas

  • Physiology

Cite this

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title = "Rapid baroreceptor resetting is unaltered by chronic hypertension in rats",
abstract = "This study compares rapid baroreceptor resetting in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Single-fiber baroreceptor activity and aortic diameter were measured in in vitro preparations. Baroreceptor pressure threshold (P(th)) and suprathreshold pressure sensitivity were measured during periods after various levels of conditioning mean arterial pressure (cMAP). The ability of a baroreceptor to reset was expressed as the resetting ratio (ΔP(th)/ΔcMAP). Rapid resetting was successfully characterized in 30 baroreceptors (18 SHR and 12 WKY). SHR blood pressures were higher, and aortic distensibility was lower than in WKY. SHR baroreceptors showed signs of chronic resetting, i.e., elevated P(th) (105.4 vs. 88.5 mmHg, SHR and WKY, respectively) and decreased suprathreshold sensitivity (0.92 vs. 1.42 spikes · s-1 · mmHg-1, SHR and WKY, respectively), but their resetting ratios were similar to WKY (0.260 and 0.237, SHR and WKY, respectively). Characterization of rapid resetting of more than one baroreceptor from single animals reveals that the resetting ratio can vary by > 50{\%} within animals. During simultaneous discharge-diameter recordings, the strain threshold was better correlated to cMAP than P(th). We conclude that the ability of baroreceptors to rapidly reset is unaltered by chronic hypertension or chronic baroreceptor resetting, and we hypothesize that rapid resetting is probably a result of an intrinsic neural property rather than vessel mechanics.",
author = "Michael Andresen and M. Yang",
year = "1989",
language = "English (US)",
volume = "256",
journal = "American Journal of Physiology - Renal Fluid and Electrolyte Physiology",
issn = "1931-857X",
publisher = "American Physiological Society",
number = "4",

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TY - JOUR

T1 - Rapid baroreceptor resetting is unaltered by chronic hypertension in rats

AU - Andresen, Michael

AU - Yang, M.

PY - 1989

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N2 - This study compares rapid baroreceptor resetting in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Single-fiber baroreceptor activity and aortic diameter were measured in in vitro preparations. Baroreceptor pressure threshold (P(th)) and suprathreshold pressure sensitivity were measured during periods after various levels of conditioning mean arterial pressure (cMAP). The ability of a baroreceptor to reset was expressed as the resetting ratio (ΔP(th)/ΔcMAP). Rapid resetting was successfully characterized in 30 baroreceptors (18 SHR and 12 WKY). SHR blood pressures were higher, and aortic distensibility was lower than in WKY. SHR baroreceptors showed signs of chronic resetting, i.e., elevated P(th) (105.4 vs. 88.5 mmHg, SHR and WKY, respectively) and decreased suprathreshold sensitivity (0.92 vs. 1.42 spikes · s-1 · mmHg-1, SHR and WKY, respectively), but their resetting ratios were similar to WKY (0.260 and 0.237, SHR and WKY, respectively). Characterization of rapid resetting of more than one baroreceptor from single animals reveals that the resetting ratio can vary by > 50% within animals. During simultaneous discharge-diameter recordings, the strain threshold was better correlated to cMAP than P(th). We conclude that the ability of baroreceptors to rapidly reset is unaltered by chronic hypertension or chronic baroreceptor resetting, and we hypothesize that rapid resetting is probably a result of an intrinsic neural property rather than vessel mechanics.

AB - This study compares rapid baroreceptor resetting in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Single-fiber baroreceptor activity and aortic diameter were measured in in vitro preparations. Baroreceptor pressure threshold (P(th)) and suprathreshold pressure sensitivity were measured during periods after various levels of conditioning mean arterial pressure (cMAP). The ability of a baroreceptor to reset was expressed as the resetting ratio (ΔP(th)/ΔcMAP). Rapid resetting was successfully characterized in 30 baroreceptors (18 SHR and 12 WKY). SHR blood pressures were higher, and aortic distensibility was lower than in WKY. SHR baroreceptors showed signs of chronic resetting, i.e., elevated P(th) (105.4 vs. 88.5 mmHg, SHR and WKY, respectively) and decreased suprathreshold sensitivity (0.92 vs. 1.42 spikes · s-1 · mmHg-1, SHR and WKY, respectively), but their resetting ratios were similar to WKY (0.260 and 0.237, SHR and WKY, respectively). Characterization of rapid resetting of more than one baroreceptor from single animals reveals that the resetting ratio can vary by > 50% within animals. During simultaneous discharge-diameter recordings, the strain threshold was better correlated to cMAP than P(th). We conclude that the ability of baroreceptors to rapidly reset is unaltered by chronic hypertension or chronic baroreceptor resetting, and we hypothesize that rapid resetting is probably a result of an intrinsic neural property rather than vessel mechanics.

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