ABSTRACT
An aqueous extract obtained from the leaves of the traditional Aboriginal medicinal plant Eremophila alternifolia R.Br. (Myoporaceae) was tested on isolated hearts of normotensive rats using the Langendorff heart preparation. A single injection of the extract into the retrograge perfusion solution induced cardioactivity, consisting of a short initial increase in force of contraction (positive inotropism), followed by a decrease in the force (negative inotropism) with simultaneous increase in heart rate (positive chronotropism) and in coronary perfusion rate. These effects were not mediated by alpha- or beta-adrenergic receptors.
Subject(s)
Cardiotonic Agents/pharmacology , Heart Rate/drug effects , Heart/drug effects , Medicine, Traditional , Myocardial Contraction/drug effects , Plant Extracts/pharmacology , Animals , Australia , Cardiotonic Agents/administration & dosage , Female , In Vitro Techniques , Male , Native Hawaiian or Other Pacific Islander , Perfusion , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Plant Leaves/chemistry , Plants, Medicinal , Rats , Rats, Wistar , Receptors, Adrenergic, alpha/drug effects , Receptors, Adrenergic, alpha/metabolism , Receptors, Adrenergic, beta/drug effects , Receptors, Adrenergic, beta/metabolismABSTRACT
Daily antepartum nursing contact and ambulatory uterine activity monitoring have been used for the early detection of preterm labor. However, it may be difficult to separate true labor from false labor. In this study, the uterine activity records of 110 women at risk for preterm birth with excessive contraction frequencies were evaluated by blinded reviewers. Maternal symptomatology and uterine activity characteristics such as low-amplitude high-frequency contractility, contraction amplitude, contraction duration, contraction interval, and contraction rhythmicity were assessed for their ability to differentiate true from threatened preterm labor. Neither maternal symptomatology nor any uterine activity characteristic other than contraction frequency could differentiate true from threatened preterm labor. Antepartum uterine activity monitoring should continue to rely on contraction frequency to identify the woman at risk for premature labor.
