Key Points
- This research aims to examine how angiotensin II affects baroreflex sensitivity in the nucleus tractus solitarius of normotensive and spontaneously hypertensive rats.
- Microinjection of angiotensin II (10 ng . kg-1 . min-1) into the nucleus tractus solitarius of urethan-anesthetized rats.
- Intravenous administration of the vasoconstrictor phenylephrine (1-12 micrograms).
- Comparison of baroreflex sensitivity between normotensive and spontaneously hypertensive rats.
- Baroreflex sensitivity significantly decreased after angiotensin II infusion (1.01 +/- 0.08) compared to control (2.41 +/- 0.51).
- Sensitivity in spontaneously hypertensive rats was lower (0.40 +/- 0.21) versus normotensive animals.
- Findings indicate that angiotensin II inhibits baroreceptor reflexes in normotensive subjects.
Structured PICO
PPopulationNormotensive urethan-anesthetized rats and spontaneously hypertensive rats (SHR)
IInterventionSubpressor infusions of angiotensin II (10 ng/kg/min) in the nucleus tractus solitarius (NTS)
OOutcomeBaroreflex sensitivity (reflex bradycardia after intravenous administration of phenylephrine)surrogate
Angiotensin II in the nucleus tractus solitarius inhibits baroreceptor reflexes in normotensive rats, suggesting a central mechanism for decreased baroreflex sensitivity in hypertension.