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 language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 256 |
| Issue number | 4 |
| State | Published - 1989 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physiology
Cite this
Rapid baroreceptor resetting is unaltered by chronic hypertension in rats. / Andresen, Michael; Yang, M.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 256, No. 4, 1989.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Rapid baroreceptor resetting is unaltered by chronic hypertension in rats
AU - Andresen, Michael
AU - Yang, M.
PY - 1989
Y1 - 1989
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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M3 - Article
VL - 256
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 4
ER -