What is the clinical evidence from this study?

Population: Canine depolarized coronary arteries. Intervention: Ca2+ in the presence of Ca2+-antagonists. Primary outcome: Ca2+-induced relaxation.

What question did this study set out to answer?

To examine the mechanisms underlying calcium-induced relaxation in depolarized canine coronary arteries in the presence of clentiazem and other calcium-channel antagonists.

October 1, 1989British Journal of PharmacologyOpen Access

Endothelium‐dependent calcium‐induced relaxation in the presence of Ca2+ ‐antagonists in canine depolarized coronary arteries

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Key result

Ca2+-induced relaxation in the presence of high concentrations of Ca2+-antagonists in canine depolarized coronary arteries is mediated through endothelium-derived relaxing factor (EDRF).

Key Points

To examine the mechanisms underlying calcium-induced relaxation in depolarized canine coronary arteries in the presence of clentiazem and other calcium-channel antagonists.
Exposed depolarized canine coronary, mesenteric, and renal arterial rings to calcium concentrations ranging from 3 x 10^-5 to 3 x 10^-3 M alongside clentiazem, diltiazem, nifedipine, or verapamil.
Assessed vascular responses in endothelium-intact, endothelium-denuded, and apposed sandwich arterial segments following treatment with oxyhaemoglobin, methylene blue, or indomethacin.
Calcium provoked unexpected relaxation in coronary arteries in the presence of clentiazem (10^-6 M), diltiazem, nifedipine, and verapamil, but failed to cause relaxation in mesenteric or renal arteries.
Relaxation was completely abolished by endothelial removal, oxyhaemoglobin (1.5 x 10^-6 M), and methylene blue (10^-5 M), while remaining unaffected by indomethacin (5 x 10^-6 M).
Endothelium-denuded coronary rings relaxed when co-incubated next to intact endothelium-containing arterial segments, indicating mediation by endothelium-derived relaxing factor without calcium-antagonist inhibition of endothelial calcium influx.

Structured PICO

Population

Canine depolarized coronary, mesenteric, and renal arteries

Intervention

Ca2+ (3 x 10(-5)-3 x 10(-3) M) in the presence of Ca2+-antagonists (clentiazem 10(-6) M, diltiazem 3 x 10(-6) M, nifedipine 3 x 10(-8) M, or verapamil 3 x 10(-6) M)

Comparator

Endothelium-denuded arteries, or treatment with oxyhaemoglobin, methylene blue, or indomethacin

Outcome

Arterial relaxationsurrogate

Ca2+-antagonists do not inhibit the Ca2+-influx required for the release and/or synthesis of endothelium-derived relaxing factor in canine coronary arteries.

Discussion

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Implication

EDRF mediates Ca2+-induced relaxation despite high-dose antagonists in canine arteries; leaves open human coronary applicability.

Cite This Study

Kikkawa et al. (1989) studied Canine depolarized coronary arteries. Ca2+ in the presence of Ca2+-antagonists was evaluated on Ca2+-induced relaxation. Ca2+-induced relaxation in the presence of high concentrations of Ca2+-antagonists in canine depolarized coronary arteries is mediated through endothelium-derived relaxing factor (EDRF).

synapsesocial.com/papers/6a8f8ba47be701926185ea88 https://doi.org/10.1111/j.1476-5381.1989.tb12645.x

View Full Paper

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Bookmark

Endothelium‐dependent calcium‐induced relaxation in the presence of Ca2+ ‐antagonists in canine depolarized coronary arteries

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Endothelium‐dependent calcium‐induced relaxation in the presence of Ca2+ ‐antagonists in canine depolarized coronary arteries

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider