What question did this study set out to answer?

To evaluate the effects of the calcium antagonists verapamil and nifedipine on mean arterial blood pressure, heart rate, and alpha-adrenoceptor-mediated pressor responses in normotensive and hypertensive rabbits.

February 1, 1987Clinical and Experimental Pharmacology and Physiology

THE EFFECTS OF CALCIUM ANTAGONISTS ON BLOOD PRESSURE AND RESPONSES TO α‐ADRENOCEPTOR AGONISTS IN HYPERTENSIVE RABBITS

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Why the study?

Do calcium antagonists (verapamil and nifedipine) differentially affect blood pressure and alpha-adrenoceptor responses in normotensive versus hypertensive rabbits?

Population

Male normotensive New Zealand white rabbits and rabbits with perinephritis hypertension

Comparison

Calcium antagonists (verapamil and nifedipine) vs Normotensive rabbits vs hypertensive rabbits

Design

Preclinical

Authors

CHCarlene A. HamiltonSt Thomas' Hospital EJE. JardinePeninsula Health DSD. J. SumnerSt. Joseph's Hospital and Medical Center

Discussion

Member takes

Implication

Indicates greater BP-lowering by calcium antagonists in hypertensive models; leaves open translation to human alpha-adrenoceptor modulation.

Key Points

To evaluate the effects of the calcium antagonists verapamil and nifedipine on mean arterial blood pressure, heart rate, and alpha-adrenoceptor-mediated pressor responses in normotensive and hypertensive rabbits.
Assessed male normotensive New Zealand white rabbits alongside rabbits with perinephritis hypertension.
Administered the calcium antagonists verapamil and nifedipine to measure baseline cardiovascular changes and pressor responses to alpha-adrenoceptor agonists including phenylephrine, alphamethyl noradrenaline, and BHT 920.
Verapamil and nifedipine caused a significantly greater absolute and percentage reduction in mean arterial pressure in hypertensive rabbits compared to normotensive controls, with heart rate responses remaining comparable.
Pressor responses to phenylephrine were attenuated by both antagonists, and alphamethyl noradrenaline responses were attenuated by nifedipine, whereas responses to the alpha-2 agonist BHT 920 remained unaltered in both groups.
Hypertensive rabbits displayed an increased baseline pressor responsiveness to phenylephrine and alphamethyl noradrenaline relative to normotensive rabbits that persisted following calcium antagonist treatment.

Structured PICO

Do calcium antagonists (verapamil and nifedipine) differentially affect blood pressure and alpha-adrenoceptor responses in normotensive versus hypertensive rabbits?

Population

Male normotensive New Zealand white rabbits and rabbits with perinephritis hypertension

Intervention

Calcium antagonists (verapamil and nifedipine)

Comparator

Normotensive rabbits vs hypertensive rabbits

Outcome

Mean arterial blood pressure, heart rate, and pressor responses to alpha-adrenoceptor agonists (phenylephrine, alphamethyl noradrenaline, BHT 920)surrogate

Calcium antagonists verapamil and nifedipine produce a greater blood pressure reduction in hypertensive rabbits and preferentially attenuate alpha-1 over alpha-2 adrenoceptor-mediated pressor responses.

Cite This Study

Hamilton et al. (1987) studied this question.

synapsesocial.com/papers/6a82a3d3d38da709b0133643 https://doi.org/10.1111/j.1440-1681.1987.tb00960.x

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Implication

Indicates greater BP-lowering by calcium antagonists in hypertensive models; leaves open translation to human alpha-adrenoceptor modulation.

THE EFFECTS OF CALCIUM ANTAGONISTS ON BLOOD PRESSURE AND RESPONSES TO α‐ADRENOCEPTOR AGONISTS IN HYPERTENSIVE RABBITS

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

THE EFFECTS OF CALCIUM ANTAGONISTS ON BLOOD PRESSURE AND RESPONSES TO α‐ADRENOCEPTOR AGONISTS IN HYPERTENSIVE RABBITS

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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