Adenosine Antagonism, a Less Desirable Characteristic of Xanthine Asthma Drugs?

2009 ◽  
Vol 49 (4) ◽  
pp. 317-320 ◽  
Author(s):  
C. G. A. Persson ◽  
I. Erjefält ◽  
J.-A. Karlsson
Keyword(s):  
Desirable Characteristic ◽  
Adenosine Antagonism

Glibenclamide attenuates adenosine-induced bradycardia and coronary vasodilatation

1991 ◽  
Vol 261 (3) ◽  
pp. H720-H727 ◽  
Author(s):  
F. L. Belloni ◽  
T. H. Hintze
Keyword(s):  
Heart Rate ◽  
Cardiovascular Responses ◽  
K Channel ◽  
Receptor Blockade ◽  
Beta Adrenergic ◽  
Coronary Vasodilatation ◽  
Cervical Vagotomy ◽  
Adenosine Antagonism ◽  
Anesthetized Dogs ◽  
Control State

The effects of the ATP-sensitive K(+)-channel blocker glibenclamide on the cardiovascular responses to adenosine in dogs were determined. Adenosine (0.01-20 mumol/kg iv) caused coronary vasodilatation, arterial hypotension, and bradycardia in dogs with either combined beta-adrenergic and muscarinic receptor blockade or with bilateral cervical vagotomy plus beta-adrenergic receptor blockade. The 50% effective dose for adenosine-induced coronary dilatation was increased from 0.13 +/- 0.04 mumol/kg in the control state to 1.1 +/- 0.5 mumol/kg after 2 mg/kg of glibenclamide (P less than 0.001). Adenosine at 5 mumol/kg reduced heart rate by 19 +/- 5% from a baseline of 158 +/- 6 beats/min in five anesthetized dogs. After glibenclamide (10 mg/kg), this dose of adenosine failed to cause a significant change in heart rate. The arterial hypotensive effects of adenosine were also attenuated by glibenclamide. Thus glibenclamide inhibited adenosine-induced bradycardia, hypotension, and coronary dilatation. On the other hand, glibenclamide did not affect the reductions in heart rate caused by vagus nerve stimulation. The mechanism of this adenosine antagonism is not known but, in the case of bradycardia, it does not appear to involve any of the steps shared in common by both adenosine-induced and vagal responses of the sinoatrial node.

Adenosine antagonism decreases metabolic but not functional recovery from ischemia

1991 ◽  
Vol 260 (1) ◽  
pp. H193-H200 ◽  
Author(s):  
D. A. Angello ◽  
J. P. Headrick ◽  
N. M. Coddington ◽  
R. M. Berne
Keyword(s):  
Functional Recovery ◽  
Left Ventricular ◽  
Low Flow ◽  
Ischemia And Reperfusion ◽  
Constant Flow ◽  
Hemodynamic Parameters ◽  
Isolated Hearts ◽  
Rat Hearts ◽  
Adenosine Antagonism ◽  
Developed Pressure

The effect of adenosine receptor antagonism on function and metabolism was examined in isolated hearts during low flow ischemia and reperfusion. Isovolumic rat hearts perfused at constant flow were subjected to 30 min of ischemia followed by 30 min of reperfusion. Infusion of vehicle or 10 microM 8-phenyltheophylline (8-PT) was initiated 10 min before ischemia and maintained throughout reperfusion. 8-PT infusion had no significant effects on hemodynamic parameters or metabolism preischemia. During ischemia, left ventricular developed pressure declined to approximately 15% of preischemic values in control and 8-PT hearts, and ATP and PCr decreased to approximately 73 and 60% of preischemic values. Inorganic phosphate (Pi) increased to 353 = 41 and 424 +/- 53% of preischemic values in control and 8-PT hearts, respectively. After reperfusion, function recovered to greater than 95% of preischemic levels in control and 8-PT hearts. Unlike control hearts, recovery of metabolites was significantly different during reperfusion in 8-PT hearts (P less than 0.05); ATP, phosphocreatine, and Pi recovered to 82 +/- 8, 71 +/- 8, and 281 +/- 27% of preischemic values, respectively. Venous purine washout was significantly greater (P less than 0.05) during reperfusion in 8-PT hearts (327 +/- 113 nmol) than in control hearts (127 +/- 28 nmol). Blockade of adenosine receptors appears to adversely affect metabolic but not functional recovery in the ischemic-reperfused myocardium.

scholarly journals Meaningful managerial action planning: The financial component

1983 ◽  
Vol 14 (4) ◽  
pp. 156-160
Author(s):  
J. G. Kotzé
Keyword(s):  
Action Planning ◽  
Top Management Teams ◽  
Financial Impact ◽  
Action Plans ◽  
Business Organizations ◽  
Short Term ◽  
Desirable Characteristic ◽  
Managerial Action ◽  
Five Elements ◽  
Innovative Orientation

An innovative orientation is a highly desirable characteristic of senior-middle and top management teams in business organizations. The formalized expression of such entrepreneurial flair may be developed in the form of action plans. Such plans consist of five elements, of which one, namely the financial component, is of prime importance. Three categories of action plans are distinguished and the evaluation of the anticipated financial impact of action plans within each category discussed. Finally, the integration of the anticipated financial results of action plans in the formal long- and short-term plans of an organization is described.

Endogenous adenosine modulates alpha 2- but not alpha 1-adrenergic constriction of coronary arterioles

1995 ◽  
Vol 268 (6) ◽  
pp. H2487-H2494 ◽  
Author(s):  
D. V. DeFily ◽  
J. L. Patterson ◽  
W. M. Chilian
Keyword(s):  
Coronary Circulation ◽  
Beta Blockade ◽  
Adenosine Receptor Antagonist ◽  
Endogenous Production ◽  
Adenosine Antagonism ◽  
Metabolic Stimulation ◽  
Metabolic Vasodilation ◽  
Baseline Diameter ◽  
Made In ◽  
Coronary Arterioles

In the coronary circulation alpha-adrenergic constriction competes with metabolic vasodilation. Because adenosine is produced by the working myocardium and metabolic stimulation results in arteriolar dilation, we tested the hypothesis that coronary arteriolar alpha-adrenergic constriction is attenuated by the endogenous production of adenosine. To test this hypothesis, using fluorescence microscopy during stroboscopic epi-illumination of the epicardial microvasculature, we measured the diameter of coronary arterioles in anesthetized open-chest dogs. Measurements were made in the presence of beta-blockade during selective alpha 1- or alpha 2-adrenoceptor activation (phenylephrine or B-HT-933, respectively) before and in the presence of the nonselective adenosine receptor antagonist 8-p-sulfophenyltheophylline (8-pSPT) and expressed as a percent change in microvascular diameter relative to baseline. alpha 1-Activation produced constriction of coronary arterioles under control conditions, which was not augmented after adenosine antagonism (-12 +/- 2 vs. -7 +/- 3%). In contrast, alpha 2-activation did not constrict coronary arterioles under control conditions; however, blockade of adenosine receptors unmasked a significant constriction (0 +/- 2 vs. -7 +/- 2%, P < 0.05). Also adenosine antagonism did not significantly alter the baseline diameter of coronary arterioles. These results demonstrate that endogenously produced adenosine modulates alpha 2-adrenergic constriction of coronary arterioles but not alpha 1-adrenergic constriction, and therefore we speculate that the competition between alpha-adrenergic constriction and metabolic vasodilation is mediated by the alpha 1-adrenoceptor.

Incorporating Infatuation in Multi-Agent Systems

2006 ◽  
Vol 10 (4) ◽  
pp. 517-521 ◽  
Author(s):  
Mirko Maleković ◽  
◽  
Mirko Čubrilo
Keyword(s):  
Positive Characteristic ◽  
Multi Agent Systems ◽  
Logical Operators ◽  
Agent Systems ◽  
Desirable Characteristic ◽  
Modal Operators ◽  
Multi Agent ◽  
Negative Characteristic

In this paper we describe incorporating infatuation in multi-agent systems. Modal operators Ii+ for infatuation (the focusing on a single attractive or desirable characteristic of another agent and then considering the total agent as that one positive characteristic) and Ii- for the reverse infatuation (the focusing on a negative characteristic of an agent and then considering the total agent as that one negative characteristic) are defined. Some relationships between the operator Ii+ and the logical operators ∧, ∨, and ⇒ are characterized.

Effect of raised portal venous pressure and postocclusive hyperemia on superior mesenteric arterial resistance in control and adenosine receptor blocked state in cats

1986 ◽  
Vol 64 (10) ◽  
pp. 1296-1301 ◽  
Author(s):  
W. Wayne Lautt
Keyword(s):  
Arterial Pressure ◽  
Adenosine Receptor ◽  
Venous Pressure ◽  
Portal Pressure ◽  
Systemic Blood Pressure ◽  
Portal Venous Pressure ◽  
Arterial Perfusion ◽  
Resistance Vessels ◽  
Adenosine Antagonist ◽  
Adenosine Antagonism

Superior mesenteric arterial (SMA) blood flow was measured in pentobarbital-anesthetized cats using a noncannulating electromagnetic flowprobe. The selective adenosine antagonist 8-phenyltheophylline (8-PT) antagonized the dilator effect of infused adenosine but not isoproterenol. The vasodilation in response to reduced arterial perfusion pressure (autoregulation) was blocked by the adenosine receptor blockade, which also reduced the degree of postocclusive (1 min) hyperemia by one-half to two-thirds. The remainder of the hyperemia may have been due partially to adenosine, since exogenous adenosine still produced a small vasodilation (26%), so effects of endogenous adenosine could also still be expected to exert a small effect. Myogenic effects appear unlikely to be the mechanism of the small remaining hyperemia, since venous pressure increments within physiologically relevant ranges did not cause altered SMA conductance, and arterial dilation in response to large decreases in arterial pressure could be blocked by adenosine antagonism. Portal pressure was increased using hepatic nerve stimulation (8 Hz) to raise pressure from 7.0 to 12.4 mmHg (1 mmHg = 133.3 Pa). The small vasoconstriction seen in the SMA was due to the rise in systemic blood pressure, since prevention of a rise in SMA pressure prevented the response and 8-PT blocked the response (previously shown to block arterial pressure–flow autoregulation). An equal rise in PVP imposed by partial occlusion of the portal vein did not lead to changes in SMA vascular conductance. Thus, we conclude that within physiologically relevant ranges of arterial and portal venous pressure, the SMA does not show myogenic responses of the resistance vessels.

Increase in plasma free fatty acids and natriuresis by xanthines may reflect adenosine antagonism

1984 ◽  
Vol 26 (1) ◽  
pp. 33-38 ◽  
Author(s):  
K. -E. Andersson ◽  
N. Johannesson ◽  
B. Karlberg ◽  
C. G. A. Persson
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Plasma Free Fatty Acids ◽  
Adenosine Antagonism

scholarly journals NEWSBOYS: SPANISH AMERICAN PATRIOT CHILDREN AND ‘THE HAZELWOOD MAGAZINE’ IN BIRMINGHAM, ENGLAND, 1820s

2020 ◽  
Vol 46 (2) ◽  
pp. e35358
Author(s):  
Karen Racine
Keyword(s):  
Public School ◽  
School System ◽  
Public School System ◽  
Close Connection ◽  
Spanish American ◽  
Pedagogical Strategies ◽  
Desirable Characteristic ◽  
Industrial Age ◽  
The Press

There was a close connection between the expansion of the press and experiments with new pedagogical strategies in the early industrial age. An expanding public school system required textbooks thus creating a whole new category of demand which appealed to printers who always on the lookout for reliable markets. At the same time, literacy was increasingly understood to be a desirable characteristic for a productive, patriotic citizenry. For a period of five years or so in the 1820s, several sons of important Spanish American patriot leaders were sent abroad to study in a progressive school called Hazelwood, near Birmingham in the heart of industrializing England. While there, the boys and their friends wrote and published a monthly periodical called the Hazelwood Magazine that clearly imitated the contents of professional newspapers andshared the underlying values of the medium.

Sign in / Sign up

Export Citation Format

Share Document