What question did this study set out to answer?

To determine whether endogenous central angiotensin II influences resting hemodynamics or the reflex suppression of renal sympathetic nerve activity during acute volume expansion in heart failure.

August 14, 2000Clinical and Experimental Pharmacology and PhysiologyOpen Access

Blockade Of Central Angiotensin II Does Not Affect The Reduction In Renal Sympathetic Nerve Activity Following A Volume Load In Heart Failure Rabbits

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Why the study?

Does central administration of losartan affect resting MAP, HR, RSNA, or the reflex reduction in RSNA following volume expansion in rabbits with doxorubicin-induced heart failure?

Population

Conscious rabbits with doxorubicin-induced heart failure (1 mg/kg, i.v., twice weekly for 6 weeks), n=11

Comparison

Losartan injected in the fourth brain ventricle… vs Ringer's solution injected in the fourth brain…

Design

Preclinical

Authors

EBEmilio BadoerRMIT University BMBP McGrathLa Trobe University

Discussion

Member takes

Implication

Central losartan leaves resting hemodynamics and volume reflexes unaltered in this rabbit HF model; hypothesis-generating for central angiotensin mechanisms before clinical translation.

Key Points

To determine whether endogenous central angiotensin II influences resting hemodynamics or the reflex suppression of renal sympathetic nerve activity during acute volume expansion in heart failure.
Heart failure was induced in conscious rabbits using intravenous doxorubicin (1 mg/kg twice weekly for 6 weeks).
Animals received fourth brain ventricle injections of either losartan (10 µg, n = 6) or Ringer's control solution (n = 5), followed by acute intravenous volume expansion using Haemaccel (2 mL/min for 30 min).
Mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were continuously recorded before and after interventions.
Central losartan administration did not significantly alter resting basal MAP, HR, or RSNA compared with Ringer's control.
Acute volume expansion induced a 40% reduction in RSNA in the control group and a 42% reduction in the losartan group, with no significant difference between treatments.
Losartan had no significant effect on MAP or HR changes during acute volume loading relative to controls.

Structured PICO

Does central administration of losartan affect resting MAP, HR, RSNA, or the reflex reduction in RSNA following volume expansion in rabbits with doxorubicin-induced heart failure?

Population

Conscious rabbits with doxorubicin-induced heart failure (1 mg/kg, i.v., twice weekly for 6 weeks), n=11

Intervention

Losartan (10 microg) injected in the fourth brain ventricle, followed by acute volume load with plasma expander Haemaccel (2 mL/min, i.v., for 30 min)

Comparator

Ringer's solution (control) injected in the fourth brain ventricle, followed by acute volume load

Outcome

Resting mean arterial blood pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), and the reflex reduction in RSNA elicited by acute volume expansionsurrogate

Central angiotensin II blockade with losartan does not significantly alter resting hemodynamics or sympathetic nerve activity responses to volume expansion in a rabbit model of heart failure.

Cite This Study

Badoer et al. (2000) studied this question.

synapsesocial.com/papers/6a82d630fb68d755121c2673 https://doi.org/10.1046/j.1440-1681.2000.03302.x

Topics

Heart failure HFrEF treatment

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August 14, 2000Clinical and Experimental Pharmacology and PhysiologyOpen Access

Blockade Of Central Angiotensin II Does Not Affect The Reduction In Renal Sympathetic Nerve Activity Following A Volume Load In Heart Failure Rabbits

View Full Paper

Ask AI

Bookmark

Why the study?

Does central administration of losartan affect resting MAP, HR, RSNA, or the reflex reduction in RSNA following volume expansion in rabbits with doxorubicin-induced heart failure?

Population

Conscious rabbits with doxorubicin-induced heart failure (1 mg/kg, i.v., twice weekly for 6 weeks), n=11

Comparison

Losartan injected in the fourth brain ventricle… vs Ringer's solution injected in the fourth brain…

Design

Preclinical

Authors

EBEmilio BadoerRMIT University BMBP McGrathLa Trobe University

Discussion

Member takes

Implication

Central losartan leaves resting hemodynamics and volume reflexes unaltered in this rabbit HF model; hypothesis-generating for central angiotensin mechanisms before clinical translation.

Key Points

To determine whether endogenous central angiotensin II influences resting hemodynamics or the reflex suppression of renal sympathetic nerve activity during acute volume expansion in heart failure.
Heart failure was induced in conscious rabbits using intravenous doxorubicin (1 mg/kg twice weekly for 6 weeks).
Animals received fourth brain ventricle injections of either losartan (10 µg, n = 6) or Ringer's control solution (n = 5), followed by acute intravenous volume expansion using Haemaccel (2 mL/min for 30 min).
Mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were continuously recorded before and after interventions.
Central losartan administration did not significantly alter resting basal MAP, HR, or RSNA compared with Ringer's control.
Acute volume expansion induced a 40% reduction in RSNA in the control group and a 42% reduction in the losartan group, with no significant difference between treatments.
Losartan had no significant effect on MAP or HR changes during acute volume loading relative to controls.

Structured PICO

Does central administration of losartan affect resting MAP, HR, RSNA, or the reflex reduction in RSNA following volume expansion in rabbits with doxorubicin-induced heart failure?

Population

Conscious rabbits with doxorubicin-induced heart failure (1 mg/kg, i.v., twice weekly for 6 weeks), n=11

Intervention

Losartan (10 microg) injected in the fourth brain ventricle, followed by acute volume load with plasma expander Haemaccel (2 mL/min, i.v., for 30 min)

Comparator

Ringer's solution (control) injected in the fourth brain ventricle, followed by acute volume load

Outcome

Resting mean arterial blood pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), and the reflex reduction in RSNA elicited by acute volume expansionsurrogate

Central angiotensin II blockade with losartan does not significantly alter resting hemodynamics or sympathetic nerve activity responses to volume expansion in a rabbit model of heart failure.

Cite This Study

Badoer et al. (2000) studied this question.

synapsesocial.com/papers/6a82d630fb68d755121c2673 https://doi.org/10.1046/j.1440-1681.2000.03302.x

Also Consider

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Topics

Heart failure HFrEF treatment

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