[The effect of oxedrine on the left ventricle and peripheral vascular resistance].
ABSTRACT The sympathomimetic substance oxedrine (Sympatol) influences, by means of its affinity to alpha- and beta-receptors, cardiac performance and peripheral vascular tone. We studied in 12 healthy male volunteers the influence of intravenous oxedrine on left ventricular contractility parameters as estimated by TM-echocardiography, on cardiac index as well as on arterial blood pressure and peripheral vascular resistance. Under continuous intravenous infusion of 4 mg/min oxedrine the systolic and mean arterial blood pressure increased significantly (p less than 0.005) while the diastolic pressure and heart rate remained unchanged. The cardiac index increased (p less than 0.001) and the peripheral vascular resistance decreased significantly (p less than 0.01). The echocardiographically determined left ventricular contractility parameters, i.e. systolic shortening fraction (SF) as well as maximal velocity of shortening of the left ventricular diameter (VCFmin) also increased significantly (p less than 0.001 and 0.005, resp.). An increase in left ventricular contractility and cardiac index with concomitant decrease of peripheral vascular resistance and without increase in heart rate implies an economical increase in cardiac performance under intravenous infusion of oxedrine.
- SourceAvailable from: Luciana Grazziotin RossatoFood and chemical toxicology: an international journal published for the British Industrial Biological Research Association 03/2011; · 2.99 Impact Factor
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ABSTRACT: Synephrine is cited as 'the active component' of plants and dietary supplements used in weight loss. It became one of the most popular stimulants present in weight-loss products after the US Food and Drug Administration had interdicted the use of ephedrine-containing dietary supplements. Synephrine is also a trace amine that can be found in vertebrates and invertebrates. Synephrine acts on several adrenergic and serotonergic receptors and its activity on trace-amine-associated receptors has long been discussed. Synephrine exists in three different positional isomers; however, only p- and m-synephrine have been described in weight-loss products. The alleged effectiveness of synephrine-containing supplements is attributed to the thermogenic effects arising from synephrine's adrenergic stimulation. The growing use of synephrine has raised concerns since it has been accompanied by reports of adverse effects. Cardiac adverse events, including hypertension, tachyarrhythmia, variant angina, cardiac arrest, QT prolongation, ventricular fibrillation, myocardial infarction, and sudden death, have been the most common adverse effects associated with synephrine intake. The mechanisms involved in synephrine-induced cardiotoxicity are still unknown since studies related to its safety are scarce. This review will address general aspects concerning the pharmacology of synephrine, but will focus on the efficacy and toxicity aspects related to the use of synephrine in weight-loss.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 11/2010; 49(1):8-16. · 2.99 Impact Factor
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ABSTRACT: The purpose of this study was to examine the acute metabolic effects of a high-energy drink in healthy, physically-active women. Ten women (20.4 +/- 0.70 y; 166.9 +/- 7.2 cm; 67.0 +/- 7.0 kg; 29.6 +/- 6.5% body fat) underwent two testing sessions administered in a randomized and double-blind fashion. Subjects reported to the laboratory in a 3-hr post-absorptive state and were provided either 140 ml of the high-energy drink (SUP; commercially marketed as Meltdown RTD) or placebo (P). Subjects consumed two 70 ml doses of SUP or P, separated by 30 min and rested in a semi-recumbent position for 3 hours. Resting oxygen consumption (VO2) and heart rate (HR) were determined every 5 min during the first 30 min and every 10 min during the next 150 min. Blood pressure (BP) was determined every 15 min during the first 30 min and every 30 min thereafter. Area under the curve (AUC) analysis was computed for VO2, whereas a 3-hour average and hourly averages were calculated for respiratory quotient (RQ), total kcal, HR, BP, and profile of mood states (POMS). AUC analysis revealed a 10.8% difference (p = 0.03) in VO2 between SUP and P. No difference in VO2 was seen between the groups in the first hour, but VO2 in SUP was significantly greater than P in the second (13.9%, p = 0.01) and third hours (11.9%, p = 0.03). A difference (p = 0.03) in energy expenditure was seen between SUP (1.09 +/- 0.10 kcal x min-1) and P (0.99 +/- 0.09 kcal x min-1) for the 3-hour period. Although no difference in energy expenditure was seen in the first hour, significant differences between SUP and P were observed in the second (1.10 +/- 0.11 kcal x min-1 and 0.99 +/- 0.09 kcal x min-1, respectively; p = 0.02) and third hour (1.08 +/- 0.11 kcal x min-1 and 0.99 +/- 0.09 kcal x min-1, respectively; p = 0.05). Average systolic BP was significantly higher (p = 0.007) for SUP (110.0 +/- 3.9 mmHg) compared to P (107.3 +/- 4.4 mmHg). No differences were seen in HR, diastolic BP, or POMS at any time point. Results showed a significant increase in energy expenditure in young, healthy women following an acute ingestion of a high-energy drink.Lipids in Health and Disease 12/2009; 8:57. · 2.31 Impact Factor