Biochemical and immunohistochemical examination of the effects of ephedrine in rat ovary tissue.

PURPOSE: It was aimed to investigate the biochemical and immunohistochemical effects of ephedrine (EPH) in bilateral ovariectomized rats. METHODS: Twenty-four Sprague Dawley female rats were divided into three groups: control group: The abdomen was opened and closed without any treatment; ischemia-reperfusion (IR) group: 2 h of ischemia followed by 2 h of reperfusion were allowed to cause IR injury; IR+EPH group: oral EPH solution (5 mg/kg) was administered for 28 days. RESULTS: Biochemical parameters were statistically significant in group comparisons. Increased interleukin-6 (IL-6) expression, degenerative preantral and antral follicle cells and inflammatory cells around blood vessels were seen in IR group. Negative IL-6 expression was observed in seminal epithelial cells, preantral and antral follicle cells in IR+EPH group. While caspase-3 activity increased in granulosa cells and stromal cells in IR group, caspase-3 expression was negative in preantral and antral follicle cells in the germinal epithelium and cortex in IR+EPH group. CONCLUSIONS: The effect of apoptosis, which occurs with the signaling that starts in the cell nucleus, caused the cessation of the stimulating effect at the nuclear level after EPH administration, and a decrease in the antioxidative effect in IR damage and inflammation in the apoptotic process.

Ephedrine Alkaloid-Independent High-Affinity Immunoglobulin-E Receptor (FcεRI) Internalization Results in CCL2 Production without Inducing Mast Cell Degranulation.

Mast cells (MCs) play an important role in allergies, leading to the development of MC-targeted therapies. Ephedra herb (Mao) has potent anti-allergic activity, but contains ephedrine alkaloids (EAs); therefore, its hazardous effects are taken into consideration during its clinical use. We previously reported that Mao attenuates robust MC degranulation by an allergen through high-affinity immunoglobulin E (IgE) receptor (FcεRI) internalization, in which an EA-independent mechanism was suggested to be at play. This study aimed to deepen our understanding of the potential of Mao against FcεRI internalization using two strains with different EA contents. Mao extracts were administered to bone marrow-derived MCs (BMMCs), and their cellular responses, including FcεRI internalization, were analyzed. In addition, physiological events were evaluated using a passive cutaneous anaphylactic (PCA) reaction mouse model. BMMCs mediate the production of diverse inflammatory mediators. Among these, the potent chemokine CCL2 is thought to be differentially regulated from other pro-inflammatory mediators. We found that Mao significantly induces CCL2 expression in BMMCs despite suppressing robust degranulation through FcεRI internalization. Importantly, this was a distinctly EAs-independent response. In the PCA reaction, local MC activation following allergen challenge was suppressed by Mao treatment, which strengthened the view that Mao sufficiently decreased the rapid activation of MCs and promoted CCL2 secretion. Collectively, these observations provide additional insights into the mechanism of Mao-induced silent FcεRI internalization in MCs and the complex and heterogeneous secretory responses operating in MCs.

Ephedra herb reduces adriamycin-induced testicular toxicity by upregulating the gonadotropin-releasing hormone signalling pathway.

OBJECTIVE: We investigated the protective effects of ephedra herb (HEPH) on adriamycin-induced testicular toxicity in rats and explored the potential mechanisms underlying these effects. METHODS: A rat model of adriamycin injury was established, and sperm motility-related indicator and oxidative stress levels in the testis were evaluated. Serum levels of sex hormones and levels of testicular cell apoptosis were detected by enzyme-linked immunosorbent assay and flow cytometry, respectively. Western blotting (WB), immunofluorescence analyses, and reverse transcription-polymerase chain reaction (RT-PCR) were performed to evaluate the gonadotropin-releasing hormone (GnRH) signalling pathway- and meiosis-related genes and proteins. In subsequent in vitro experiments, adriamycin was used to stimulate GC-1 cells, which were treated with HEPH, ephedrine, or pseudoephedrine. Cell viability was assessed using flow cytometry to detect apoptosis and reactive oxygen species, whereas the GnRH signalling pathway and levels of meiosis-related genes and proteins were evaluated by InCell WB, a high-content imaging system, and RT-PCR. RESULTS: Per in vivo experiments, HEPH restored testicular weight and function, sperm characteristics, serum and tissue hormonal levels, and antioxidant defences and significantly activated the GnRH signalling pathway- and meiosis-related protein levels. All protective effects of HEPH against adriamycin-induced injury were antagonised by the GnRH antagonist cetrorelix. In vitro, HEPH, ephedrine, and pseudoephedrine significantly reduced adriamycin-induced GC-1 cell apoptosis and reactive oxygen species levels and increased the expression of GnRH signalling pathway- and meiosis-related proteins. The effect of pseudoephedrine was greater than that of ephedrine, and these findings may be an important basis for understanding the effects of HEPH.

Ephedrine as a lead compound for the development of new DPP-IV inhibitors.

AIM: Extracts from Ephedra species have been reported to be effective as antidiabetics. A previous in silico study predicted that ephedrine and five ephedrine derivatives could contribute to the described antidiabetic effect of Ephedra extracts by inhibiting dipeptidyl peptidase IV (DPP-IV). Finding selective DPP-IV inhibitors is a current therapeutic strategy for Type 2 diabetes mellitus management. Therefore, the main aim of this work is to experimentally determine whether these alkaloids are DPP-IV inhibitors. Materials & methods: The DPP-IV inhibition of Ephedra's alkaloids was determined via a competitive-binding assay. Then, computational analyses were used in order to find out the protein-ligand interactions and to perform a lead optimization. RESULTS: Our results show that all six molecules are DPP-IV inhibitors, with IC50 ranging from 124 µM for ephedrine to 28 mM for N-methylpseudoephedrine. CONCLUSION: Further computational analysis shows how Ephedra's alkaloids could be used as promising lead molecules for designing more potent and selective DPP-IV inhibitors.

Aggregated N-of-1 trials for unlicensed medicines for small populations: an assessment of a trial with ephedrine for myasthenia gravis.

BACKGROUND: Inexpensive medicines with a long history of use may currently be prescribed off-label for rare indications. Reimbursement is at the discretion of health insurance companies, and may be unpredictable. The example addressed was ephedrine as add-on treatment for myasthenia gravis. Stakeholders from academia, a patient organization, the Dutch National Health Care Institute (NHCI) and Dutch Medicines Evaluation Board (MEB) advised on the trial design. The NHCI and MEB agreed to provide scientific advice on the suitability of the evidence generated by the trial, for regulatory decisions. This paper describes the feasibility of the trial and the utility of its aggregated results. RESULTS: The trialists experienced the trial as feasible. Retrospective interviews showed that the trial as performed was acceptable to patients. The treatment effect in the primary outcome measure, muscle strength, was statistically significant when inferred to the population level, though the effect size was modest. Secondary outcomes were statistically significant in a preplanned, fixed effects analysis within the four patients. The NHCI advised that it could potentially make reimbursement decisions based on the Fitting Evidence framework, should the trialists decide to apply for reimbursement. The MEB advised that for a licensing decision, the N-of-1 design is a last-resort option for demonstrating treatment benefit in a rare disease. N-of-1 trials alone do not provide enough evidence on potential risk. The MEB found the current trial inconclusive. It suggested doing a 2-armed trial of longer duration, possibly with a different outcome measure (postponement of corticosteroid use). It suggested engaging a consultancy or commercial sponsor, should the trialists decide to seek market authorization of the drug. CONCLUSIONS: In theory, evidence from aggregated N-of-1 trials is suitable for use in licensing and reimbursement decisions. The current example illustrates differences in interpretation of N-of-1 results by health authorities. In the era of personalized medicine, consensus is required on the interpretation of data from study designs geared to small groups. Demonstrating effectiveness of inexpensive medicines in small populations may require involvement of non-commercial parties, to preserve affordability.

Radiotracers for cardiac sympathetic innervation: transport kinetics and binding affinities for the human norepinephrine transporter.

INTRODUCTION: Most radiotracers for imaging of cardiac sympathetic innervation are substrates of the norepinephrine transporter (NET). The goal of this study was to characterize the NET transport kinetics and binding affinities of several sympathetic nerve radiotracers, including [(11)C]-(-)-meta-hydroxyephedrine, [(11)C]-(-)-epinephrine, and a series of [(11)C]-labeled phenethylguanidines under development in our laboratory. For comparison, the NET transport kinetics and binding affinities of some [(3)H]-labeled biogenic amines were also determined. METHODS: Transport kinetics studies were performed using rat C6 glioma cells stably transfected with the human norepinephrine transporter (C6-hNET cells). For each radiolabeled NET substrate, saturation transport assays with C6-hNET cells measured the Michaelis-Menten transport constants Km and Vmax for NET transport. Competitive inhibition binding assays with homogenized C6-hNET cells and [(3)H]mazindol provided estimates of binding affinities (KI) for NET. RESULTS: Km, Vmax and KI values were determined for each NET substrate with a high degree of reproducibility. Interestingly, C6-hNET transport rates for 'tracer concentrations' of substrate, given by the ratio Vmax/Km, were found to be highly correlated with neuronal transport rates measured previously in isolated rat hearts (r(2)=0.96). This suggests that the transport constants Km and Vmax measured using the C6-hNET cells accurately reflect in vivo transport kinetics. CONCLUSION: The results of these studies show how structural changes in NET substrates influence NET binding and transport constants, providing valuable insights that can be used in the design of new tracers with more optimal kinetics for quantifying regional sympathetic nerve density.

Influence of substrate structure on substrate binding to the renal organic cation/H+ exchanger.

The carrier-mediated exchange of H+ for organic cations ("OC/H+ exchange") is the active step in OC secretion in renal proximal tubules. Although hydrophobicity is known to be an important criterion for binding of substrates to this transporter, the degree to which steric parameters of substrate structure influence binding to the exchanger is unclear. We examined this issue by measuring the inhibition of OC/H+ exchange produced by a group of quaternary ammonium compounds which share a common structural motif: an N1-pyridinium residue. Activity of the OC/H+ exchanger was determined by measuring transport of [14C]tetraethylammonium (TEA) in brush-border membrane vesicles (BBMV) from rabbit renal cortex. Transport was measured in the presence of a pH gradient (pHin 6.0; pHout 7.5) to maximize TEA/H+ exchange. Apparent inhibitory constants (Ki values) for each test agent were measured. The test agents included 4-phenylpyridiniums and 3-phenylpyridiniums, quinoliniums and acridiniums. The planar structure of these compounds permits a direct test of whether the presence of planar hydrophobic mass in different orientations relative to the pyridinium motif exerts a systematic effect on substrate binding to the OC/H+ exchanger. The hydrophobicity of each group of compounds was systematically varied by addition of different substituents at the quaternary nitrogen. Whereas decreases in Ki proved to be proportional to hydrophobicity, the position of the phenyl-ring substituent(s) had no effect on substrate interaction with the exchanger. The results led to the development of a preliminary quantitative structure-activity relationship (QSAR) correlating substrate hydrophobicity and substrate binding to the OC/H+ exchanger. This QSAR was used to predict the binding of 1-methyl-4-phenylpyridinium (MPP+), (+) and (-)nicotine, (+) and (-)ephedrine, quinine and quinidine to the OC/H+ exchanger. Molecular graphics representation of the 3D structures of the test agents was used to develop a working model of a hydrophobic, planar receptor surface on the OC/H+ exchanger against which substrates are suggested to interact during binding. Development of the QSAR and receptor surface model open the way to quantitative tests of the specific physical and structural determinants of substrate selectivity by the renal OC/H+ exchanger.

Effects of cardiac sympathetic innervation on coronary blood flow.

BACKGROUND: The role of cardiac sympathetic nerves in regulating coronary blood flow is controversial. We sought to determine the degree to which cardiac efferent sympathetic signals modulate coronary blood flow. The heterogeneous sympathetic reinnervation in transplanted hearts provides a model for studying the vasomotor responses to adrenergic stimulation in reinnervated and denervated coronary territories of the same heart. METHODS: We studied 14 cardiac-transplant recipients who had normal coronary arteries and no evidence of rejection and 8 normal subjects. We used positron-emission tomography with [(11)C]hydroxyephedrine, an analogue of norepinephrine, to delineate sympathetic innervation. Using [(13)N]ammonia, we measured myocardial blood flow at rest, during adenosine-induced hyperemia, and in response to sympathetic stimulation induced by cold pressor testing. RESULTS: In the transplant recipients, the uptake of [(11)C]hydroxyephedrine was greater in the territory served by the left anterior descending artery (0.15+/-0.01) than in those served by the right coronary artery (0.07+/-0.01, P<0.001) or the circumflex artery (0.09+/-0.01, P<0.001). The basal flow was similar in all three regions, as was the percent increase in flow during hyperemia. However, the increase in flow in response to cold pressor testing was higher in the territory of the left anterior descending artery (46+/-10 percent) than in those of the right coronary artery (16+/-5 percent, P=0.01) or the circumflex artery (23+/-6 percent, P=0.06), although the changes in hemodynamics and levels of circulating catecholamines were similar. No such regional differences were observed in the normal subjects. CONCLUSIONS: Increases in coronary blood flow in response to sympathetic stimulation correlated with the regional norepinephrine content in the cardiac sympathetic-nerve terminals. These findings suggest that cardiac adrenergic signals play an important part in regulating myocardial blood flow.

Carcinogenicity of N-nitrosoephedrine in rats.

N-nitrosoephedrine was administered orally to 32 male Srague--Dawley rats at doses of 120 mg/kg body wt. twice weekly. Of the treated animals, 50% died with preneoplastic and malignant lesions mainly in the liver, lung and forestomach. The median time of death of tumor bearing animals was 522 days after the beginning of the experiment. The observation of hyperkeratosis, papillomas, and 1 squamous cell carcinoma of the forestomach suggests that the compound not only exhibits systemic effects but is probably also a weak local carcinogen.

[Use of gas chromatography--mass spectrometry system in toxicology]. / Aplikace systému plynové chromatografie - hmotové spektrometrie v toxikologii

In the presented paper experiences with the practical usage of gas chromatography - mass spectrometry system are given. Cases of the identification of forbidden doping drugs and some significant groups of medicaments are described. The possibility of the identification of drug metabolites and interfering substances is pointed as well. Examples of chemical ionization usage are given from literature papers. This work points out the advantages of both methods for the identification of drugs in biological material. The priority and possibility of both procedures are evaluated critically.