Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Syncope is defined as a temporary interruption of cerebral perfusion with a sudden and transient loss of consciousness and spontaneous recovery. Approximately one third of the population experiences syncope at least once during a lifetime. Presyncopal signs and symptoms, including weakness, headache, blurred vision, diaphoresis, nausea, and vomiting are sometimes present for seconds or minutes prior to loss of consciousness. After syncope, the patients may present with persisting drowsiness, headache, dizziness, nausea, but not usually confusion. Causes of syncope have been categorized as cardiovascular, non-cardiovascular, and unexplained. Cardiovascular causes can be subdivided into structural heart disease, coronary heart disease, and arrhythmia. Non-cardiovascular causes include neurological, metabolic, psychiatric and other disorders.Orthostatic hypotension - one of the most frequent causes of syncope - has manifold etiologies comprising various neurological and internal diseases. Orthostatic hypotension usually can be attributed to an impairment of peripheral vasoconstriction or to a reduction of the intravascular volume. Signs and symptoms, including the above prodromi are often present just after rising from a supine or sitting position. Frequently, blood pressure decreases significantly without an increase in heart rate. Autonomic cardiovascular modulation is often reduced. Many of the patients with "unexplained" syncope experience neurally mediated (i. e. neurocardiogenic or vasovagal) syncope. In these patients, cardiovascular control may be stable for an extended period of time during orthostatic stress, then there is a sudden decrease in blood pressure and heart rate. Neurocardiogenic or neurally mediated syncope can be associated with painful or emotionally stressful situations such as anxiety or fear, with prolonged standing or specific trigger situations such as micturition, defecation, coughing or sneezing, visceral or carotid sinus stimulation, or with trigeminal or glossopharyngeal neuralgia. So far, the mechanisms of neurocardiogenic syncope are not completely understood. The passive 60 degrees to 70 degrees head-up tilt test is useful for the diagnosis of orthostatic and neurally mediated syncope. The sensitivity of the test can be improved by additional pharmacological provocation, e. g. by isoproterenol, or by increased orthostatic stress using lower body negative pressure stimulation. For the treatment of syncope one should first consider non-pharmacological options. Patients with orthostatic hypotension should avoid rapid changes of the body position from supine to standing, as well as high room temperature or other situations inducing peripheral vasodilatation. An increased intake of sodium and fluids, mild physical exercise or so-called postural counter-maneuvers can improve orthostatic tolerance. Among the drugs recommended for pharmacologic treatment are mineralocorticoids (e. g. fludrocortisone), vasoconstrictor agents (e. g. ephedrine, midodrine), adenosine receptor blockers (theophylline) and beta2-blockers (propanolol), anticholinergic agents, e. g. scopolamine or disopyramide, and negative cardiac inotropes, e. g. beta1-adrenergic blockers or disopyramide. Serotonin reuptake inhibitors (e. g. fluoxetine, sertraline), alpha2-adrenergic agonists (clonidine), central nervous system stimulants such as methylphenidate or phentermine are thought to be beneficial in specific cases. Cardiac pacemakers often seem to be recommended without adequate indication. The antidiuretic, V2-receptor specific, vasopressin analogue desmopressin increases the intravascular volume. Erythropoietin improves anemia and red blood cell decrease and augments blood pressure and cerebral oxygenation. In postprandial hypotension, octreotide, a somatostatin analogue, prostaglandin inhibitors such as indomethacin or ibuprofen, as well as metoclopramide or two cups of coffee per day might be beneficial.
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PMID:[Syncope - a systematic overview of classification, pathogenesis, diagnosis and management]. 1182 26

Activation of either the A(1) or the A(3) adenosine receptor (A(1)R or A(3)R, respectively) elicits delayed cardioprotection against infarction, ischemia, and hypoxia. Mitochondrial contribution to the progression of cardiomyocyte injury is well known; however, the protective effects of adenosine receptor activation in cardiac cells with a respiratory chain deficiency are poorly elucidated. The aim of our study was to further define the role of A(1)R and A(3)R activation on functional tolerance after inhibition of the terminal link of the mitochondrial respiratory chain with sodium azide, in a state of normoxia or hypoxia, compared with the effects of the mitochondrial ATP-sensitive K(+) channel opener diazoxide. Treatment with 10 mM sodium azide for 2 h in normoxia caused a considerable decrease in the total ATP level; however, activation of adenosine receptors significantly attenuated this decrease. Diazoxide (100 muM) was less effective in protection. During treatment of cultured cardiomyocytes with hypoxia in the presence of 1 mM sodium azide, the A(1)R agonist 2-chloro-N(6)-cyclopentyladenosine was ineffective, whereas the A(3)R agonist 2-chloro-N(6)-iodobenzyl-5'-N-methylcarboxamidoadenosine (Cl-IB-MECA) attenuated the decrease in ATP level and prevented cell injury. Cl-IB-MECA delayed the dissipation in the mitochondrial membrane potential during hypoxia in cells impaired in the mitochondrial respiratory chain. In cells with elevated intracellular Ca(2+) concentration after hypoxia and treatment with NaN(3) or after application of high doses of NaN(3), Cl-IB-MECA immediately decreased the elevated intracellular Ca(2+) concentration toward the diastolic control level. The A(1)R agonist was ineffective. This may be especially important for the development of effective pharmacological agents, because mitochondrial dysfunction is a leading factor in the pathophysiological cascade of heart disease.
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PMID:Role of adenosine A1 and A3 receptors in regulation of cardiomyocyte homeostasis after mitochondrial respiratory chain injury. 1568 7

The adenosine A2B receptor (A2BAR) has been identified as an important therapeutic target in cardiovascular disease, however in vitro and in vivo targeting has been limited by the paucity of pharmacological tools, particularly potent agonists. Interestingly, 2-((6-amino-3,5-dicyano-4-(4-(cyclopropylmethoxy)phenyl)-2-pyridinyl)thio)acetamide (BAY60-6583), a potent and subtype-selective A2BAR agonist, has the same core structure as 2-amino-6-[[2-(4-chlorophenyl)-1,3-thiazol-4-yl]methylsulfanyl]-4-[4-(2-hydroxyethoxy)phenyl]pyridine-3,5-dicarbonitril (capadenoson). Capadenoson, currently classified as an adenosine A1 receptor (A1AR) partial agonist, has undergone two Phase IIa clinical trials, initially in patients with atrial fibrillation and subsequently in patients with stable angina. Capadenoson has also been shown to decrease cardiac remodeling in an animal model of advanced heart failure and a capadenoson derivative, neladenoson bialanate, recently entered clinical development for the treatment of chronic heart failure. The therapeutic effects of capadenoson are currently thought to be mediated through the A1AR. However, the ability of capadenoson to stimulate additional adenosine receptor subtypes, in particular the A2BAR, has not been rigorously assessed. In this study, we demonstrate that capadenoson does indeed have significant A2BAR activity in physiologically relevant cells, cardiac fibroblasts and cardiomyocytes, which endogenously express the A2BAR. Relative to the non-selective adenosine receptor agonist NECA, capadenoson was a biased A2BAR agonist with a preference for cAMP signal transduction over other downstream mediators in cells with recombinant and endogenous A2BAR expression. These findings suggest the reclassification of capadenoson as a dual A1AR/A2BAR agonist. Furthermore, a potential A2BAR contribution should be an important consideration for the future clinical development of capadenoson-like therapeutics, as the A2BAR can promote cardioprotection and modulate cardiac fibrosis in heart disease.
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PMID:Capadenoson, a clinically trialed partial adenosine A1 receptor agonist, can stimulate adenosine A2B receptor biased agonism. 2834 25