Abstract:
OBJECTIVE:Previous studies on multicellular preparations have shown that hypertrophied cardiac muscle from the spontaneously hypertensive rat (SHR) has a prolonged action potential. The first aim of the present study was to determine whether the action potential of isolated left ventricular myocytes was similarly prolonged and to study the underlying membrane currents that might be responsible. The second aim was to evaluate the L-type calcium current amplitude of SHR myocytes, as we have recently shown that they have an increased contraction and an increase in the calcium trigger entering via the L-type calcium channel might be one possible mechanism for this. METHODS:The electrophysiological characteristics of left ventricular myocytes isolated from the SHR were compared with those from normotensive control rats. Action potentials were recorded with microelectrodes. Cells were voltage-clamped and the membrane currents elicited by steps to different potentials were analysed. Blockers of potassium and calcium currents were used to reveal the contribution made by these currents to net membrane currents. RESULTS:SHR myocytes had prolonged action potentials. The action potential duration of SHR myocytes at 90% repolarization was found to be longer, although at 20% and 50% repolarization no difference was found. There was no difference in the resting membrane potential between SHR and control myocytes. Using a voltage clamp we studied the L-type calcium current and potassium currents. The major change in SHR myocytes was a decrease in the magnitude (normalized to the membrane capacitance) of the inward rectifier potassium current elicited by negative potentials. There was no detectable difference in either the transient outward or delayed rectifier potassium currents. We also found no difference in the magnitude, time course or voltage dependence of L-type calcium current in hypertrophied SHR myocytes. CONCLUSIONS:First, the action potential of SHR myocytes was prolonged compared with control myocytes. Secondly, the main change in SHR myocytes was that pulses to negative potentials elicited a lower inward rectifier potassium current. A reduction in the density of inward rectifier channels might play a role in prolonging the SHR action potential, since a lower outward repolarizing current will flow through inward rectifier potassium channels during the SHR action potential repolarization. Thirdly, there was no difference in L-type calcium current density or time course between SHR and control myocytes. Thus, a change in L-type calcium current probably plays no role in causing the prolonged SHR action potential or the increased contraction of hypertrophied SHR ventricular myocytes. Finally, the prolonged action potential in SHR myocytes may itself be one factor responsible for the increased contraction of these cells.
journal_name
J Hypertensjournal_title
Journal of hypertensionauthors
Brooksby P,Levi AJ,Jones JVdoi
10.1097/00004872-199306000-00005subject
Has Abstractpub_date
1993-06-01 00:00:00pages
611-22issue
6eissn
0263-6352issn
1473-5598journal_volume
11pub_type
杂志文章abstract:BACKGROUND:The usefulness of the hypertensive retinopathy classification by Keith-Wagener-Barker (KWB) in clinical practice remains controversial. The simplified Mitchell-Wong grading, combining the two initial KWB' grades in one stage, is proposed as an alternative method; both systems are poorly validated regarding t...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000000702
更新日期:2015-11-01 00:00:00
abstract:BACKGROUND:Postmenopausal estrogen replacement, with or without progestins, has been related to lower cardiovascular risks. OBJECTIVE:We investigated whether the actions of estrogen on vascular resistance contribute to this cardioprotective effect. DESIGN AND METHODS:In a 6-month double-blind study, pre- and post-tre...
journal_title:Journal of hypertension
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1097/00004872-200102000-00014
更新日期:2001-02-01 00:00:00
abstract:OBJECTIVE:It is not well known which exercise intensity is needed to obtain blood pressure reductions in response to endurance training. We therefore compared the effect of training at lower and higher intensity on blood pressure, and, in addition on other cardiovascular risk factors, in at least 55-year-old sedentary ...
journal_title:Journal of hypertension
pub_type: 杂志文章,随机对照试验
doi:10.1097/HJH.0b013e328322cf60
更新日期:2009-04-01 00:00:00
abstract:OBJECTIVE:Hypertension affects cerebrovascular autoregulation and increases the risk of cerebrovascular events and dementia. Notably, it is associated with cerebrovascular remodeling and lower resting cerebral blood flow (CBF). We wanted to determine, using arterial spin-labeling-MRI, the impact of a head-down tilt (HD...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000002709
更新日期:2020-12-09 00:00:00
abstract:OBJECTIVES:Arterial stiffness is associated with excess morbidity and mortality, independently of other cardiovascular risk factors. Age is the main determinant responsible for arterial wall changes leading to arterial stiffening. Environmental and genetic factors may however influence the magnitude of the effects of a...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-200103000-00008
更新日期:2001-03-01 00:00:00
abstract:OBJECTIVE:We aimed to investigate whether adjustment for frailty influences the relationship of blood pressure with mortality in elderly patients with type 2 diabetes mellitus (T2DM). METHODS:Patients aged 60 years and older (n = 858) were selected from a prospective observational cohort study of primary care patients...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000000555
更新日期:2015-06-01 00:00:00
abstract:OBJECTIVE:We tested the hypothesis that qualitative microalbuminuria (MAU) screening in a practice setting would identify non-diabetic hypertensive patients at high risk of developing cardiovascular disease. DESIGN:We enrolled general practitioners throughout Germany, who obtained histories, physical examinations, and...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-199602000-00011
更新日期:1996-02-01 00:00:00
abstract:BACKGROUND:Choice of antihypertensive drugs is also based on the expected burden of adverse events associated with each class of agents, and we have recently identified treatment discontinuation for adverse events as a measure of treatment tolerability frequently reported in randomized controlled trials (RCTs). OBJECT...
journal_title:Journal of hypertension
pub_type: 杂志文章,meta分析,评审
doi:10.1097/HJH.0000000000001052
更新日期:2016-10-01 00:00:00
abstract:BACKGROUND AND OBJECTIVES:Although 24-h urinary measure to estimate sodium and potassium excretion is the gold standard, it is not practical for large studies. We compared estimates of 24-h sodium and potassium excretion from a single morning fasting urine (MFU) using three different formulae in healthy individuals. M...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000000122
更新日期:2014-05-01 00:00:00
abstract::Adequate evaluation of automated sphygmomanometers, in terms of safety, accuracy, mechanical reliability, patient acceptability and ability to record ambulatory blood pressure is essential before these devices are used in clinical practice and in clinical trials. We have evaluated the accuracy and performance of the A...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-199007000-00003
更新日期:1990-07-01 00:00:00
abstract:OBJECTIVES:In this cross-sectional study we compared the central aortic systolic pressure (CASP), peripheral brachial systolic pressure (PSP), peripheral brachial diastolic pressure (PDP) and augmentation index (AIx) between normotensive offspring of nonhypertensive parents (ONT) and normotensive offspring with at leas...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0b013e328355207b
更新日期:2012-08-01 00:00:00
abstract:BACKGROUND:Some patients with essential hypertension manifest greater than normal urinary excretion of albumin (UAE). Authors of a few retrospective studies have suggested that there is an association between microalbuminuria and cardiovascular risk. OBJECTIVE:To evaluate whether microalbuminuria is associated with a ...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-199816090-00014
更新日期:1998-09-01 00:00:00
abstract:BACKGROUND:Orthostatic hypotension, postprandial hypotension, and carotid sinus hypersensitivity are hypotensive syndromes with high prevalence in older people. However, their pathophysiology and prognostic significance remain largely unknown. METHODS:In a retrospective cohort study of 313 consecutive patients visitin...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0b013e328352b9fd
更新日期:2012-06-01 00:00:00
abstract:OBJECTIVES:Many different stress echocardiographic and radionuclide perfusion imaging tests have been proposed for detecting epicardial coronary artery disease (CAD) in hypertensive patients. Their relative diagnostic and prognostic value has not been exactly established. BACKGROUND:A positive exercise electrocardiogr...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-200103000-00018
更新日期:2001-03-01 00:00:00
abstract:OBJECTIVE:The repair process at the site of injury after percutaneous coronary intervention (PCI) is dominated by neointimal formation composed mainly of smooth muscle cells (SMC). Endothelin-1 (ET-1) is a powerful vasoconstrictor and SMC mitogen. Endothelin-converting enzyme (ECE) is the final key enzyme of endothelin...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/01.hjh.0000217854.97369.8c
更新日期:2006-04-01 00:00:00
abstract:OBJECTIVE:Nephrin, a cytoskeletal protein which localizes to the slit pore of podocytes, may play a role in proteinuria. This study examines the possible relationship between nephrin expression and albuminuria in normotensive and hypertensive diabetic rats. METHODS:Streptozotocin diabetes was induced in both Wistar-Ky...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-200205000-00034
更新日期:2002-05-01 00:00:00
abstract:BACKGROUND:The retinal microvasculature provides a window to the cerebral vasculature and enables examination of changes in retinal caliber that may mimic those occurring in cerebrovascular disease. The association of central arterial stiffness and retinal vessel caliber in a population sample is not fully understood. ...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000002252
更新日期:2020-02-01 00:00:00
abstract:OBJECTIVES:Current clinical guidelines of primary aldosteronism recommend adrenalectomy (AdX) for unilateral primary aldosteronism based on the studies showing the potential superiority of AdX over the medical treatment. However, since most medically treated cases consisted of bilateral primary aldosteronism and all su...
journal_title:Journal of hypertension
pub_type: 杂志文章,多中心研究
doi:10.1097/HJH.0000000000002070
更新日期:2019-07-01 00:00:00
abstract:OBJECTIVE:To evaluate the effects of angiotensins acting at the rostral ventrolateral medulla (RVLM) on the cardiovascular adjustments following haemorrhage. DESIGN:Changes in mean arterial pressure (MAP) and heart rate (HR) produced by micro-injections of angiotensin II (Ang II) and angiotensin (Ang)-(1-7) and differ...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-199917080-00014
更新日期:1999-08-01 00:00:00
abstract:BACKGROUND:The urinary isoflavonoid equol inhibits membrane Na-K-Cl cotransporters at similar concentrations to those at which furosemide inhibits them, but the significance of this action is not known. OBJECTIVE:To investigate the potential salidiuretic and vascular actions of equol in the rat. METHODS:Renal functio...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-199715110-00015
更新日期:1997-11-01 00:00:00
abstract:OBJECTIVES:To evaluate the associations of high awake blood pressure (BP), high asleep BP, and nondipping BP, determined by ambulatory BP monitoring (ABPM), with left ventricular hypertrophy (LVH) and geometry. METHODS:Black and white participants (n = 687) in the Coronary Artery Risk Development in Young Adults study...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000002221
更新日期:2020-01-01 00:00:00
abstract:OBJECTIVES:Blood pressure (BP) measurement in atrial fibrillation (AF) patients is problematic and automated monitors are regarded as inaccurate. The optimal procedure for validating BP monitors in AF is questionable. This study evaluated the accuracy of a novel professional oscillometric upper-arm cuff device (Microli...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000002684
更新日期:2020-10-16 00:00:00
abstract:BACKGROUND:In sub-Saharan Africa, cardiovascular disease is becoming a leading cause of death, with high blood pressure as number one risk factor. In Nigeria, access and adherence to hypertension care are poor. A pharmacy-based hypertension care model with remote monitoring by cardiologists through mHealth was piloted ...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000001877
更新日期:2019-02-01 00:00:00
abstract:CLINICAL STUDIES:In clinical renal transplantation studies, recipients of a renal graft from a donor with a genetic predisposition to hypertension had higher blood pressures and required more antihypertensive treatment than recipients of a renal graft from a normotensive donor. In addition, blood pressure normalization...
journal_title:Journal of hypertension
pub_type: 社论
doi:10.1097/00004872-199309000-00001
更新日期:1993-09-01 00:00:00
abstract:OBJECTIVE:We tested the reproducibility of ambulatory blood pressure (ABP), BP variability, and BP reduction in hypertensive patients. METHODS:Forty-two hypertensive patients were enrolled, and ABP monitoring (ABPM) was performed four times in each patient: twice before and twice after the treatment. Morning BP was de...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0b013e3283378477
更新日期:2010-05-01 00:00:00
abstract:OBJECTIVES:To explore the association of different types of blood pressure (BP) variability measures estimated from either short-term ambulatory reading-to-reading or long-term clinic visit-to-visit BP records with long-term survival in an elderly treated hypertensive population. METHODS:A subset of patients (n = 508)...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/HJH.0000000000001652
更新日期:2018-05-01 00:00:00
abstract::The benefit of blood pressure-lowering therapy in individuals with normal blood pressure who are at high cardiovascular risk creates a challenge in how best to advocate such therapy. Arguments based on a putative causal role for blood pressure and the need to reduce blood pressure may be less likely to succeed than ar...
journal_title:Journal of hypertension
pub_type: 社论
doi:10.1097/HJH.0b013e3280127961
更新日期:2007-05-01 00:00:00
abstract:OBJECTIVE:Construction of prognostically relevant endpoints for clinical trials in hypertension has increasingly included coronary revascularization with myocardial infarction (MI) as manifestations of coronary artery disease. However, whether coronary revascularization and MI predict other cardiovascular events simila...
journal_title:Journal of hypertension
pub_type: 临床试验,杂志文章
doi:
更新日期:2010-06-01 00:00:00
abstract:OBJECTIVE:To determine whether acutely lowering insulin levels with somatostatin in obese, insulin-resistant hypertensive individuals reduces arterial pressure and forearm vascular resistance; and whether these changes are reversed by restoring insulin levels during continuing somatostatin infusion. SUBJECTS:Subjects ...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:
更新日期:1996-01-01 00:00:00
abstract:OBJECTIVE:The genetic background of orthostatic hypotension, an important risk factor for future cardiovascular morbidity and mortality, was investigated. DESIGN AND METHODS:The study subjects comprised 415 community-dwelling individuals, who were free from any cardiovascular complications, aged 50 years or older (mea...
journal_title:Journal of hypertension
pub_type: 杂志文章
doi:10.1097/00004872-200204000-00022
更新日期:2002-04-01 00:00:00