Key result
Angiotensin I and II relax contracted cat tracheal muscle in a dose-dependent, aspirin-sensitive manner.
Why the study?
The mechanisms underlying the relaxing effects of angiotensin I and angiotensin II on isolated cat tracheal muscle contracted by 5-hydroxytryptamine were unclear.
Angiotensin I and II induce relaxation of isolated cat tracheal muscle via a mechanism inhibited by aspirin, independent of conversion to A II or specific A II receptors.
Caution against extrapolating cat tracheal findings to human airways; leaves open mechanistic and translational research on prostaglandin-angiotensin interactions.
The effects of Asp1-beta-amide-Val5-angiotensin II (A II) and Asp1-Ile5-angiotensin I (A I) have been studied on the isolated continuously superfused cat tracheal muscle contracted by 5-hydroxytryptamine (5-HT). Both peptides have been shown to induce dose-dependent relaxation on this muscle. Similar effects have been obtained with synthetic bradykinin, prostaglandin E2 (PGE2), noradrenaline and histamine. The effects of bradykinin, A I and A II have been shown to be inhibited by aspirin but not by propranolol, metiamide, SC 19220 or a specific, competitive antagonist of A II. The relaxing effect of A I is not due to the conversion of decapeptide to octapeptide A II. The possible mechanism of the relaxing effects of A I and A II on the cat isolated tracheal muscle is discussed.
No takes yet. Share an insight, caveat, or question.
Tìrker et al. (1976) studied this question. Angiotensin I and Angiotensin II was evaluated on Muscle relaxation. Angiotensin I and Angiotensin II induced dose-dependent relaxation of isolated cat tracheal muscle contracted by 5-hydroxytryptamine, an effect inhibited by aspirin.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: