The role of adenosinergic system in patients with orthostatic intolerance

2019 ◽  
Author(s):  
Zora Lazurova ◽  
Peter Mitro ◽  
Marta Jakubova ◽  
Milos Simurda ◽  
Eva Durovcova ◽  
...  
2004 ◽  
Vol 52 ◽  
pp. S384-S385
Author(s):  
S. M. Grenon ◽  
N. Sheynberg ◽  
X. Xiao ◽  
C. D. Ramsdell ◽  
S. Hurwitz ◽  
...  

2004 ◽  
Vol 52 (Suppl 2) ◽  
pp. S384.6-S385
Author(s):  
S. M. Grenon ◽  
N. Sheynberg ◽  
X. Xiao ◽  
C. D. Ramsdell ◽  
S. Hurwitz ◽  
...  

2001 ◽  
Vol 3 (29) ◽  
pp. 1-10 ◽  
Author(s):  
Tahir Tellioglu ◽  
David Robertson

The norepinephrine transporter (NET) has a major role in terminating the neurochemical signal established by the neurotransmitter norepinephrine (NE) in the synaptic cleft. The NET is also the initial site of action for therapeutic antidepressants, and drugs such as cocaine and amphetamines. Polymorphisms in the NET gene have been identified, and associations with several disorders such as depression have been proposed but not established. However, evidence of a direct association between a genetic mutation of the NET and an autonomic clinical syndrome has recently emerged. A patient and her identical twin were evaluated for typical symptoms of orthostatic intolerance (OI), a disorder mainly characterised by elevated heart rate on standing, and both were found to have clinical and laboratory signs of abnormal uptake of NE. Sequence analysis of the patients' NET gene identified a mutation that resulted in more than 98% loss of function as compared with the wild-type gene. This article reconsiders the important role of the NET protein in the regulation of the nervous and cardiovascular systems, reviews the literature for its polymorphisms and their suggested clinical manifestations, and finally focuses on the effects of its defect on the pathophysiology of OI, the only confirmed direct association between a genetic mutation of the NET and a clinical syndrome.


1997 ◽  
Vol 103 (2) ◽  
pp. 128-133 ◽  
Author(s):  
Giris Jacob ◽  
David Robertson ◽  
Rogelio Mosqueda-Garcia ◽  
Andrew C. Ertl ◽  
Rose Marie Robertson ◽  
...  

2018 ◽  
Vol 96 (8) ◽  
pp. 772-782 ◽  
Author(s):  
Min Jiang ◽  
Qiang Lyu ◽  
Yun-Gang Bai ◽  
Huan Liu ◽  
Jing Yang ◽  
...  

Recent studies have suggested that microgravity-induced arterial remodelling contributes to post-flight orthostatic intolerance and that multiple mechanisms are involved in arterial remodelling. However, the initial mechanism by which haemodynamic changes induce arterial remodelling is unknown. Focal adhesions (FAs) are dynamic protein complexes that have mechanotransduction properties. This study aimed to investigate the role of FAs in simulated-microgravity-induced basilar and femoral arterial remodelling. A 4-week hindlimb-unweighted (HU) rat model was used to simulate the effects of microgravity, and daily 1-hour intermittent artificial gravity (IAG) was used to prevent arterial remodelling. After 4-week HU, wall thickness, volume of smooth muscle cells (SMCs) and collagen content were increased in basilar artery but decreased in femoral artery (P < 0.05). Additionally, the expression of p-FAK Y397 and p-Src Y418 was increased and reduced in SMCs of basilar and femoral arteries, respectively, by HU (P < 0.05). The number of FAs was increased in basilar artery and reduced in femoral artery by HU (P < 0.05). Furthermore, daily 1-hour IAG prevented HU-induced differential structural adaptations and changes in FAs of basilar and femoral arteries. These results suggest that FAs may act as mechanosensors in arterial remodelling by initiating intracellular signal transduction in response to altered mechanical stress induced by microgravity.


2021 ◽  

Viral persistence following acute COVID infection is increasingly being reported by patients and gradually being recognized as a medical syndrome. Like much about COVID, this so-called Long COVID is perplexing. It is associated with numerous symptoms, foremost among them profound fatigue, and often occurs in a relapsing/remitting pattern. There is one “living” guideline for managing Long COVID and even terminology and definitions of the syndrome are in flux. Long COVID occurs in patients who have recovered from the acute infection and this may be viral persistence, a form of autoimmunity, or the long-term results of organ damage sustained during the acute infection. Symptoms have been reported up to six months after acute infection with no clear association between the severity of the acute infection and the presence or absence of Long COVID. The symptoms of the acute illness do not necessarily align with the symptoms of Long COVID. Disruptions to the autonomic function in Long COVID are particularly puzzling, including orthostatic intolerance syndrome (which may not have occurred during the acute infection). Loss of the sense of smell and taste is one symptom that appears common in both acute and Long COVID; on the other hand, fever is more prevalent in acute than Long COVID. Research is urgently needed to better understand Long COVID, for example: what is the role of elevated biomarkers such as D-dimer and C-reactive protein in Long COVID? Is Long COVID one or more than one syndrome? How can patients with Long COVID be appropriately treated?


2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Michelle L. Harrison ◽  
Josh F. Lee ◽  
Skyler Brown ◽  
R. Matthew Brothers

2010 ◽  
Vol 20 (S3) ◽  
pp. 135-139 ◽  
Author(s):  
Jeffrey R. Boris

AbstractDysfunction of the autonomic nervous system, or dysautonomia, is an uncommon disease. Postural orthostatic tachycardia syndrome is one of the several types of dysautonomia. Postural orthostatic tachycardia syndrome, also known as chronic orthostatic intolerance, is the most common but least severe of the dysautonomic disorders; it will serve as the model for evaluation and management of the other dysautonomias. Overall, these patients can have variable dysfunction of the autonomic nervous system that is more severe than that observed in typical neurocardiogenic syncope. Frequently, providers are not familiar with either the evaluation or the management of this syndrome, or are just not interested in doing so. This article attempts to describe strategies for evaluation and management of postural orthostatic tachycardia syndrome. The diagnosis of postural orthostatic tachycardia syndrome is made by the finding of orthostatic intolerance associated with a pulse greater than 120 beats per minute in the first 10 minutes of upright position or an elevation in pulse greater than 30 beats per minute in the first 10 minutes of upright position. Overall, these patients can have variable dysfunction of the autonomic nervous system that is more severe than that seen in typical neurocardiogenic syncope. A wide variety of associated symptoms may exist and these symptoms can have tremendous impact on the lives of the patients and their families. Management of these patients can be difficult as well as rewarding. It is helpful to perform an extensive education up front with these patients and their families. Interventions for patients with postural orthostatic tachycardia syndrome typically fall into two broad categories: non-pharmacological and pharmacological. Non-pharmacological therapies are varied, but are based primarily on ensuring adequate status of intravascular fluid. Polypharmacy may be required to control symptoms associated with postural orthostatic tachycardia syndrome. On account of the severity of their symptoms, these patients frequently have difficulty in completing their school assignments. The physician may need to help support the attempts of the family to work with the school to help the patient stay in school. As postural orthostatic tachycardia syndrome is underdiagnosed and poorly understood, it is a disease that provides an excellent opportunity to perform research. The most important studies would be those that aim to elucidate an aetiology and a pathophysiology of postural orthostatic tachycardia syndrome. In the final analysis, the role of the cardiologist in the evaluation and management of a patient with dysautonomia is to help a patient with severe disability to feel as if they are normal, or much closer to it.


2017 ◽  
Vol 51 (5) ◽  
pp. 243-247 ◽  
Author(s):  
Mohammed Ruzieh ◽  
Lillian Batizy ◽  
Osama Dasa ◽  
Carson Oostra ◽  
Blair Grubb

2007 ◽  
Vol 32 (2) ◽  
pp. 311-317 ◽  
Author(s):  
Ben T.A. Esch ◽  
Shannon S.D. Bredin ◽  
Mark J. Haykowsky ◽  
Jessica M. Scott ◽  
Darren E.R. Warburton

In this review, we examine the growing body of evidence suggesting that the pericardium plays an important role in modulating cardiac function during conditions of physiological stress. Specifically, we discuss the effects of the pericardium on left ventricular filling and compliance. Furthermore, we reveal that there is increasing evidence to support the contention that the pericardium is capable of adaptation in response to volume loading. We also provide data that suggests endurance-training is a good example of a physiological stressor capable of causing pericardial remodelling. These adaptations appear particularly beneficial during exercise and may explain (in part) the common finding of stroke volume increasing during exercise to a greater extent in endurance-trained athletes. However, this adaptation may also partially explain the increased susceptibility to orthostatic intolerance in endurance athletes.


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