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Effects of an aqueous extract of Terminalia arjuna on isolated rat atria and thoracic aorta
Author(s) -
Karamsetty Mallikharjuna,
Ferrie Thomas J.,
Kane K. A.,
Gray A. I.
Publication year - 1995
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.2650090808
Subject(s) - terminalia arjuna , propranolol , inotrope , isoprenaline , contraction (grammar) , pharmacology , thoracic aorta , aorta , chemistry , aqueous extract , medicine , traditional medicine , anesthesia , terminalia , stimulation
Terminalia arjuna (Combretaceae) is used traditionally in ayurveda, to treat a variety of cardiovascular disorders. The aims of this study were to characterize the positive inotropic effect of the aqueous extract of T. arjuna bark in isolated paced rat left atria and to study its effects on a vascular smooth muscle preparation, the rat thoracic aorta. The crude and semipurified aqueous extracts produced a positive inotropic effect of rat atria and the maximum contraction was comparable to that produced by isoprenaline. The positive inotropic effect of the extract was completely blocked by a β‐adrenoceptor blocker, propranolol, and an uptake‐1 blocker, cocaine. In precontracted aorta, the aqueous extract produced a contraction followed by relaxation. Propranolol did not block the relaxant effect of the aqueous extract. It is concluded that the positive inotropic effect of the aqueous extract was mediated via an action on β 1 ‐adrenoceptors and was likely to be due to the release of noradrenaline from the sympathetic nerve endings. The vasorelaxant effect of the extract, however, was not mediated via an action on β 2 adrenoceptor.