Key Points
- To determine how plasma renin activity changes with age and correlates with systolic blood pressure in inbred spontaneously hypertensive versus normotensive rats.
- Generated spontaneously hypertensive and normotensive rat strains via repeated inbreeding.
- Measured plasma renin activity longitudinally across ages 5 to 45 weeks, evaluating the impact of brief ether anesthesia.
- Examined the correlation between plasma renin activity and systolic blood pressure once chronic hypertension was established.
- Brief ether anesthesia induced a 2- to 3-fold increase in plasma renin activity in both hypertensive and normotensive strains.
- Plasma renin activity was significantly higher in spontaneously hypertensive rats at 5–7 weeks than in age-matched normotensive controls, but declined after week 9 to become significantly lower by week 45.
- Systolic blood pressure exhibited a significant inverse relationship with plasma renin activity once hypertension was established in both strains.
Structured PICO
PPopulationTwo new strains of spontaneously hypertensive and normotensive rats
IInterventionObservation over time (from 5-7 weeks to 45 weeks of age) and brief ether anesthesia
CComparatorNormotensive rats of the same age
OOutcomePlasma renin activitysurrogate
The renin-angiotensin system may play a role in the early pre-hypertensive stage of genetic hypertension in rats, but is unlikely to maintain established spontaneous hypertension.