Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1323099 (sympathomimetic)
 2,957 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A young, otherwise healthy man presented with an acute retinal artery obstruction following excessive use of oxymethazolone hydrochloride 0.5% (Afrin) nasal spray. Platelet coagulation studies indicated a platelet aggregation hypersensitivity to adenosine diphosphate and epinephrine. A predisposition for sympathomimetic drug-induced platelet fibrin embolus formation appears to be the cause of the retinal artery obstruction in this case.
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PMID:Branch retinal artery occlusion after excessive use of nasal spray. 241 95

The effects of three different types of beta-adrenoceptor blocking agents on platelet aggregation and on platelet and plasma cyclic AMP content have been studied in 14 patients with mild hypertension given each drug in turn for two weeks. The drugs were a non-selective blocking agent with high intrinsic sympathomimetic activity, pindolol, the nonspecific blocking agent propranolol, and the beta 1-selective metoprolol. The threshold values of ADP and adrenaline for irreversible platelet aggregation were significantly higher for pindolol and metoprolol than for propranolol. The cyclic AMP content of platelets was higher during pindolol and metoprolol than during propranolol treatment. Pindolol produced a substantial increase in plasma cyclic AMP relative to the other two drugs. Thus, platelet aggregation and cyclic AMP formation are influenced by beta-adrenoceptor blockade in proportion to intrinsic sympathomimetic activity and affinity for different beta-adrenoceptor subtypes.
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PMID:Effects of three beta-blockers with different pharmacodynamic properties on platelet aggregation and platelet and plasma cyclic AMP. 290 89

Inhibitory actions on adenosine diphosphate (ADP)-induced platelet aggregation of atenolol, dl- and d-D-32, IPS-339, pindolol and propranolol were investigated in guinea pigs for the purpose of obtaining a clue about a possible mechanism for the disaggregatory phenomenon of beta-adrenoceptor blocking agents. The effects of verapamil and procaine on guinea pig platelet aggregation were also examined. All of these agents including verapamil and procaine showed a dose-dependent inhibitory effect on platelet aggregation, and their relative potencies determined on the basis of the molar concentrations producing a 50% inhibition of ADP-induced aggregation were in descending order: IPS-339 greater than propranolol greater than verapamil greater than dl-D-32 not equal to d-D-32 greater than pindolol greater than procaine greater than atenolol. This order of relative potencies of the inhibitory actions of these test compounds on platelet aggregation was well correlated to those of local anaesthetic action in guinea pigs (r = 0.932, P less than 0.01) and lipophilicity (r = -0.899, P less than 0.01), while it did not agree with the orders of potency of beta-adrenoceptor blocking action, intrinsic sympathomimetic action and vasodilator action. From these results, it may be reasonable to propose that inhibitory actions of beta-adrenoceptor blocking agents and local anaesthetics on platelet aggregation are caused through the same mechanism or through a very similar one.
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PMID:Drug-induced inhibition of guinea pig platelet aggregation unrelated to their beta-adrenolytic actions. 613 13

Platelet aggregation induced by shear stress is distinct from that induced by an agonist such as ADP or collagen. The physiological significance of shear-induced platelet aggregation was investigated by measuring the effects of the presence of physiological concentrations of epinephrine. Blood samples were taken from 10 normal volunteers who had received no drugs known to interfere with platelet functions for 1 month preceding the study. Blood was mixed with 1/10 volume of 3.1% sodium citrate solution. Platelet-rich plasma and platelet-poor plasma were prepared by centrifugation at 100 g for 15 min and 2,000 g for 15 min, respectively. The platelet count of platelet-rich plasma was adjusted to 3 x 10(5)/microliters. Shear-induced platelet aggregation in platelet-rich plasma was determined using a modified cone and plate viscometer controlled by a personal computer system. The intensity of light transmission was continuously recorded. The percent platelet aggregation was calculated according to the Lambert-Beer equation. Platelet aggregation occurred under both low (12 dyn/cm2) and high (108 dyn/cm2) shear stress. More significant aggregation was observed under high shear stress. The maximum percent platelet aggregation was 44.7 +/- 13.4%, which increased to 53.3 +/- 10.0% in the presence of 10 pg/ml epinephrine. With 100 pg/ml of epinephrine, shear-induced platelet aggregation induced by 12 dyn/cm2 shear significantly increased, but the effects on shear-induced platelet aggregation of 108 dyn/cm2 shear were not uniform. Shear-induced platelet aggregation is enhanced by physiological concentrations of epinephrine, which may be a cause of arterial thrombotic occlusion in sympathomimetic states.
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PMID:[Low concentrations of epinephrine can augment shear stress-induced platelet aggregation]. 820 39

Cardiac matrix metalloproteinases (MMPs) stimulated by the sympathomimetic action of angiotensin II (AII) exacerbate chamber diastolic stiffening in models of subacute heart failure. Here we tested the hypothesis that MMP inhibition prevents such stiffening by favorably modulating high-energy phosphate (HEP) stores more than by effects on matrix remodeling. Dogs were administered AII i.v. for 1 week with tachypacing superimposed in the last two days (AII+P; n = 8). A second group (n = 9) underwent the same AII+P protocol but was preceded by oral treatment with an MMP inhibitor PD166793 [(S)-2-(4-bromo-biphenyl-4-sulfonylamino-3-methyl butyric acid] 1 week before and during the AII+P period. Pressure-volume analysis was performed in conscious animals, and myocardial tissue was subjected to in vitro and in situ zymography, collagen content, and HEP analysis (high-performance liquid chromatography). As reported previously, AII+P activated MMP9 and MMP2 and specifically exacerbated diastolic stiffening (+130% in chamber stiffness). PD166793 cotreatment prevented these changes, although myocardial collagen content, subtype, and cross-linking were unaltered. AII+P also reduced ATP, free energy of ATP hydrolysis (DeltaG(ATP)), and phosphocreatine while increasing free [ADP], AMP catabolites (nucleoside-total purines), and lactate. PD166793 reversed most of these changes, in part due to its inhibition of AMP deaminase. MMP activation may influence cardiac diastolic function by mechanisms beyond modulation of extracellular matrix. Interaction between MMP activation and HEP metabolism may play an important role in mediating diastolic dysfunction. Furthermore, these data highlight a potential major role for increased AMP deaminase activity in diastolic dysfunction.
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PMID:Metalloproteinase inhibitor counters high-energy phosphate depletion and AMP deaminase activity enhancing ventricular diastolic compliance in subacute heart failure. 1643 97

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.
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PMID:Ephedra alkaloids inhibit platelet aggregation. 2017 77