What question did this study set out to answer?

To investigate the acute effects of angiotensin II on myocardial diastolic properties and determine the specific receptor and signaling pathways involved.

January 16, 2006British Journal of PharmacologyOpen Access

Angiotensin II acutely decreases myocardial stiffness: a novel AT1, PKC and Na⁺/H⁺exchanger‐mediated effect

Q: What is the clinical evidence from this study?

Population: Myocardial stiffness (n=56). Intervention: Angiotensin II vs. Baseline / absence of AngII / presence of antagonists. Primary outcome: Resting tension and end-diastolic pressure.

View Full Paper

Ask AI

Bookmark

Key result

Acute administration of Angiotensin II decreased myocardial stiffness, reducing resting tension by 46+/-4% and end-diastolic pressure from 10.3 to 5.9 mmHg via AT1, PKC, and NHE pathways.

Why the study?

Does angiotensin II acutely decrease myocardial stiffness in rabbit papillary muscles and in situ hearts?

Population

Rabbit papillary muscles and in situ rabbit hearts

Comparison

Angiotensin II vs Baseline and Angiotensin II with various…

Design

Preclinical

Authors

ALAdelino Leite‐MoreiraHeart Failure / Cardiomyopathy PCPaulo Castro‐ChavesSynopsys (Switzerland)PPPedro Pimentel‐NunesUniversidade do Porto

Discussion

Member takes

Implication

May indicate acute diastolic modulation by Ang II in animals; leaves open human translation and clinical relevance.

Key Points

To investigate the acute effects of angiotensin II on myocardial diastolic properties and determine the specific receptor and signaling pathways involved.
Exposed isolated rabbit papillary muscles to graded concentrations of angiotensin II (10⁻⁹ to 10⁻⁵ M) alone or combined with AT1 antagonists (losartan, ZD-7155), an AT2 antagonist (PD-123,319), a PKC inhibitor (chelerythrine), or an NHE inhibitor.
Assessed passive length-tension curves in papillary muscles and evaluated hemodynamics during intravenous angiotensin II infusion (10 µg/kg/min) in intact rabbit hearts in situ.
Angiotensin II (10⁻⁵ M) increased active tension by 43.3 ± 6.25% and resting muscle length by 1.96 ± 0.4%, with re-adjustment of length yielding a 46 ± 4% decrease in resting tension.
In intact hearts at matched systolic pressure (112 mmHg), angiotensin II reduced end-diastolic pressure from 10.3 ± 0.3 to 5.9 ± 0.5 mmHg and minimal diastolic pressure from 8.4 ± 0.5 to 4.6 ± 0.6 mmHg.
AT1 receptor blockade eliminated all contractile and stiffness alterations, while PKC or NHE inhibition selectively attenuated resting length and tension changes without altering inotropy.

Structured PICO

Does angiotensin II acutely decrease myocardial stiffness in rabbit papillary muscles and in situ hearts?

Population

Rabbit papillary muscles and in situ rabbit hearts

Intervention

Angiotensin II (10^-9 to 10^-5 M in vitro, 10 microg kg^-1 min^-1 in vivo)

Comparator

Baseline (absence of Angiotensin II) and Angiotensin II with various inhibitors (losartan, ZD-7155, PD-123,319, chelerythrine, 5-(N-methyl-N-isobutyl)-amiloride)

Outcome

Diastolic properties of the myocardium (myocardial stiffness, resting muscle length, resting tension, end-diastolic pressure)surrogate

Angiotensin II acutely decreases myocardial stiffness via AT1 receptor activation, mediated by PKC and NHE, suggesting a novel mechanism of acute neurohumoral modulation of diastolic function.

Cite This Study

Leite‐Moreira et al. (2006) studied Myocardial stiffness (n=56). Angiotensin II vs. Baseline / absence of AngII / presence of antagonists was evaluated on Resting tension and end-diastolic pressure. Acute administration of Angiotensin II decreased myocardial stiffness, reducing resting tension by 46+/-4% and end-diastolic pressure from 10.3 to 5.9 mmHg via AT1, PKC, and NHE pathways.

synapsesocial.com/papers/6a0ea76006ecbe833447a927 https://doi.org/10.1038/sj.bjp.0706659

View Full Paper

Ask AI

Bookmark

Angiotensin II acutely decreases myocardial stiffness: a novel AT1, PKC and Na⁺/H⁺exchanger‐mediated effect

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Angiotensin II acutely decreases myocardial stiffness: a novel AT1, PKC and Na⁺/H⁺exchanger‐mediated effect

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider