What question did this study set out to answer?

To evaluate the chronic effects of central versus systemic administration of the AT1 receptor blocker losartan on blood pressure and arterial baroreflex function in spontaneously hypertensive rats.

June 1, 1994American Journal of Hypertension

Chronic Effects of Central and Systemic Administration of Losartan on BloodPressure and Baroreceptor Reflex in Spontaneously Hypertensive Rats

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Why the study?

Does losartan reduce blood pressure and improve baroreceptor reflex in spontaneously hypertensive rats?

Population

Spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY), aged 12 to 16 weeks

Comparison

Losartan administered via subcutaneous infusion… vs Isotonic saline solution subcutaneously or…

Design

Preclinical

Follow-up

14 days

Authors

YKYuhei KawanoPreventive Cardiology KYKaoru YoshidaMeitetsu Hospital HMHiroaki MatsuokaGeneral / Preventive / Lipids

Discussion

Member takes

Implication

Losartan restores baroreflex sensitivity with BP reduction in SHR; leaves open translation of central AT1 effects to human hypertension.

Key Points

To evaluate the chronic effects of central versus systemic administration of the AT1 receptor blocker losartan on blood pressure and arterial baroreflex function in spontaneously hypertensive rats.
Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) aged 12 to 16 weeks received 14-day continuous infusions of losartan subcutaneously (10 mg/kg/day) or intracerebroventricularly (1 or 10 mg/kg/day), alongside respective vehicle controls.
On day 14, baroreflex control of heart rate was evaluated using intravenous phenylephrine, and pressor responses to intravenous angiotensin II (100 ng/kg) were measured in conscious rats.
Subcutaneous losartan reduced blood pressure across the 14-day infusion period in both strains, with significantly greater hypotensive reduction in SHR, while also restoring baroreflex sensitivity in SHR.
Intracerebroventricular losartan at 1 mg/kg/day did not alter blood pressure or baroreflex control in either strain, whereas 10 mg/kg/day produced blood pressure reductions, baroreflex improvements, and angiotensin II pressor inhibition comparable to subcutaneous administration at the same dose.

Structured PICO

Does losartan reduce blood pressure and improve baroreceptor reflex in spontaneously hypertensive rats?

Population

Spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY), aged 12 to 16 weeks

Intervention

Losartan administered via subcutaneous infusion (10 mg/kg/day) or intracerebroventricular infusion (1 or 10 mg/kg/day) for 14 days

Comparator

Isotonic saline solution subcutaneously or intracerebroventricular artificial cerebrospinal fluid

Outcome

Blood pressure and arterial baroreceptor reflex (baroreflex control of heart rate)surrogate

Systemic and high-dose central administration of losartan lowers blood pressure and improves baroreflex sensitivity in spontaneously hypertensive rats, highlighting the role of endogenous angiotensin II.

Cite This Study

Kawano et al. (1994) studied this question.

synapsesocial.com/papers/6a848877c2c8a33f31f7b61e https://doi.org/10.1093/ajh/7.6.536

Topics

Hypertension management

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Chronic Effects of Central and Systemic Administration of Losartan on BloodPressure and Baroreceptor Reflex in Spontaneously Hypertensive Rats

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Topics

Chronic Effects of Central and Systemic Administration of Losartan on BloodPressure and Baroreceptor Reflex in Spontaneously Hypertensive Rats

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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