What is the clinical evidence from this study?

Population: Experimental heart failure (n=15). Intervention: Propranolol vs. Non-treated. Primary outcome: Cardiac response to catecholamines and beta-adrenergic receptor density (p=<0.05).

What question did this study set out to answer?

To evaluate the cellular mechanisms and functional effects of a 14-day propranolol regimen on left ventricular response to catecholamines and beta-adrenoceptor density in experimental heart failure.

November 12, 1995Fundamental and Clinical Pharmacology

Propranolol therapy in experimental heart failure in rabbits improves cardiac response to catecholamines without beta‐adrenoceptor up‐regulation

Q: What are the key findings of this study?

Propranolol treatment for 14 days improved ventricular response to catecholamines in rabbits with heart failure, without changing beta-adrenergic receptor density (27.8 fmoles/mg/proteins in both).

Q: What question did this study set out to answer?

To evaluate the cellular mechanisms and functional effects of a 14-day propranolol regimen on left ventricular response to catecholamines and beta-adrenoceptor density in experimental heart failure.

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Key result

Propranolol improves ventricular response to catecholamines in HF rabbits without altering beta-adrenergic receptor density.

P<0.05
n=15

Why the study?

Does propranolol treatment improve cardiac response to catecholamines and alter beta-adrenoceptor density in rabbits with experimental heart failure?

Key Points

To evaluate the cellular mechanisms and functional effects of a 14-day propranolol regimen on left ventricular response to catecholamines and beta-adrenoceptor density in experimental heart failure.
Studied 15 rabbits with volume and pressure overload-induced heart failure allocated to either a 14-day propranolol treatment (N=7) or no treatment (N=8).
Monitored left ventricular hemodynamics and dimensions using an intraventricular catheter and ultrasonic crystals during isoproterenol and norepinephrine infusions.
Quantified myocardial beta-adrenoceptor density in crude membrane preparations using 125I-cyanopindolol radioligand binding.
Isoproterenol stimulation induced a significantly lower heart rate (p < 0.005) and greater systolic diameter shortening (p < 0.05) in treated rabbits compared to non-treated controls.
Norepinephrine infusion increased systolic shortening percentage and end-diastolic diameter under matched pressures in the treated group, whereas no change occurred in the non-treated group.
Beta-adrenoceptor density was identical in treated and non-treated groups (27.8 fmoles/mg protein), remaining significantly lower than in healthy control rabbits (58.2 fmoles/mg protein, p < 0.01).

Structured PICO

Does propranolol treatment improve cardiac response to catecholamines and alter beta-adrenoceptor density in rabbits with experimental heart failure?

Population

15 rabbits with experimental heart failure induced by volume and pressure overload, treated with propranolol for 14 days or untreated.

Intervention

Propranolol treatment for 14 days

Comparator

No treatment (8 rabbits with experimental heart failure)

Outcome

Left ventricular function response to catecholamines (isoproterenol and norepinephrine) and beta-adrenergic receptor densitysurrogate

Main Result

p-value: p=<0.05

In a rabbit model of heart failure, propranolol improved the ventricular response to catecholamines through myocardial protection rather than beta-adrenoceptor up-regulation.

Discussion

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Implication

Supports receptor-independent protection by propranolol in rabbit HF; leaves open clinical relevance and mechanisms in human disease.

Cite This Study

Xiong et al. (1995) studied Experimental heart failure (n=15). Propranolol vs. Non-treated was evaluated on Cardiac response to catecholamines and beta-adrenergic receptor density (p=<0.05). Propranolol treatment for 14 days improved ventricular response to catecholamines in rabbits with heart failure, without changing beta-adrenergic receptor density (27.8 fmoles/mg/proteins in both).

synapsesocial.com/papers/6aa3005e21270d8a3eea5090 https://doi.org/10.1111/j.1472-8206.1995.tb00529.x

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Propranolol therapy in experimental heart failure in rabbits improves cardiac response to catecholamines without beta‐adrenoceptor up‐regulation

Key Points

Structured PICO

Main Result

Discussion

Implication

Cite This Study

Propranolol therapy in experimental heart failure in rabbits improves cardiac response to catecholamines without beta‐adrenoceptor up‐regulation

Key Points

Structured PICO

Main Result

Discussion

Implication

Cite This Study

Also Consider

Also Consider