Ephedra alkaloids inhibit platelet aggregation

Abstract

Sympathomimetics, such as Ephedra alkaloids, are associated with an increased incidence of intracerebral hemorrhage believed to be secondary to concomitant elevations in blood pressure. We hypothesized that sympathomimetics decrease platelet aggregation. Reductions in epinephrine-mediated platelet aggregation by ephedrine, phenylpropanolamine, and racemic amphetamine were determined by measuring the changes that these sympathomimetics induced in the optical density of platelet-rich plasma from healthy individuals. Intracellular signal transduction was followed ex vivo by assaying the release of intracellular cyclic AMP and the ligand for the cytokine chemoreceptor 5 (RANTES) into platelet rich plasma. The effect of ephedrine on epinephrine-mediated increases in platelet selectin (CD62p) activation was assessed with flow cytometry. Data were analyzed with repeated-measures analyses of variance. Aggregation responses to epinephrine were greatly reduced in the presence of commonly used sympathomimetics such as ephedrine, phenylpropanolamine, and racemic amphetamine that have been found in cold remedies, appetite suppressants, or used in the treatment of attention-deficit hyperactivity disorder, respectively. Ephedrine diminished aggregation responses to ADP and gamma-thrombin, and this sympathomimetic reduced RANTES exocytosis, basal CD62p expression, and aggregation in platelets exposed to caffeine. Caffeine enhanced the effect of ephedrine on platelet function, and phenylpropanolamine amplified the inhibitory effect of aspirin on platelet aggregation. Sympathomimetics significantly alter platelet function, and they may increase the potential for bleeding independently of their effects on blood pressure. Despite restrictions imposed on their use, the consumption of sympathomimetics should be considered when any patient presents with findings of cerebral hemorrhage.

Acetazolamide increases locomotion, exploratory behavior, and weight loss following social stress: A treatment for emotional eating?

“…We sought to identify pharmacologic antagonists that could modify the behavior outcomes of social stress that often results in emotional eating and unhealthy weight gain. We have shown that many of the effects of the stress hormone, epinephrine, through α2AR signal transduction are mediated by carbonic anhydrase-dependent chloride/bicarbonate exchange [ 22 , 23 ].…”

“…These effects of the amphetamine could be due to the inhibition by these sympathomimetics of central α2ARs in the paraventricular hypothalamus (PVH) that modify satiety and locomotion [ [13] , [14] , [15] , [16] , [17] , [18] ]. As noted above, we have previously shown that α2AR signal transduction can be inhibited by blocking carbonic anhydrase-dependent chloride/bicarbonate transport with acetazolamide in platelets and vascular smooth muscle [ 22 , 23 ]. In this current report, we show that acetazolamide demonstrates potent anorectic properties, increases locomotion, and diminishes weight gain during exposure to social stress similar to the action of amphetamines.…”

“…Alpha-2 adrenergic receptors (α2AR) of catecholaminergic neurons of the paraventricular hypothalamus mediate satiety and spontaneous locomotion [ [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] ]. We reported that amphetamines and sympathomimetic agents antagonize α2AR-dependent signal transduction mediated by chloride/bicarbonate co-transport [ 22 , 23 ]. We hypothesized that in addition to amphetamines and sympathomimetics, drugs that inhibit cellular chloride/bicarbonate antiport would similarly induce anorexia, locomotion, and diminish weight gain with a greater safety profile – especially in disorders such as depression or social isolation where there is a decrease in activity and an increase in emotional eating.…”

A koronavírus-járvány hatása a komplementer terápiás gyógymódok igénybevételére elektív sebészeti műtétek előtt

“…A biztonságos felhasználásnak előfeltétele a készítmény összetevőinek alapos ismerete, melynek figyelmen kívül hagyásával alkalmazásuk számos gyógyszer-interakciót és szövődményt okozhat [20,21]. A gyógynövények esetén fokozottan számolni kell e veszélyeikkel a perioperatív ellátás kapcsán, mellékhatásaik érinthetik a véralvadás rendszerét, a szív-és érrendszert, a hormonális rendszert, a vese-és májműködést [22][23][24][25][26][27][28][29].…”

Gyógynövények használata elektív műtéti beavatkozás előtt. Kérdőíves felmérés egy egyetemi klinika és egy városi kórház betegei körében

“…Ismerni kell mind a hatóanyagokat, mind azok élettani és terápiás hatásait, melyek figyelmen kívül hagyásával alkalmazásuk számos gyógyszer-interakciót és szövődményt hozhat létre [1][2][3]. Többféle gyógynövény esetében merült fel potenciálisan káros hatásuk a haemostasisra [4][5][6], a cardiovascularis rendszerre [7,8], az endokrin rendszerre, a máj-és veseműködésre [9,10].…”