Rasheda Chowdhury
Imperial College London, National Heart and Lung Institute, Graduate Student
ABSTRACT coupling and action potentials during early reperfusion are thought to contribute to reperfusion arrhythmogenesis. We tested the hypothesis that modulation of gap junctional coupling can reduce the incidence of reperfusion... more
ABSTRACT coupling and action potentials during early reperfusion are thought to contribute to reperfusion arrhythmogenesis. We tested the hypothesis that modulation of gap junctional coupling can reduce the incidence of reperfusion arrhythmias and used optical mapping to assess the mechanisms of any antiarrhythmic effect.
Research Interests:
ABSTRACT It is uncertain whether moderate conduction slowing through gap junctional uncoupling on its own, in the absence of action potential or structural changes, is sufficient to be pro-arrhythmic. We used optical mapping: (1) to study... more
ABSTRACT It is uncertain whether moderate conduction slowing through gap junctional uncoupling on its own, in the absence of action potential or structural changes, is sufficient to be pro-arrhythmic. We used optical mapping: (1) to study the effects of carbenoxolone (CBX), a gap junction uncoupler, on conduction velocity and action potential duration and (2) to assess the effects of moderate conduction slowing and gap junctional uncoupling on arrhythmia vulnerability in structurally normal hearts.
Research Interests:
The relative roles of the gap-junctional proteins connexin40 (Cx40) and connexin43 (Cx43) in determining human atrial myocardial resistivity is unknown. In addressing the hypothesis that changing relative expression of Cx40 and Cx43... more
The relative roles of the gap-junctional proteins connexin40 (Cx40) and connexin43 (Cx43) in determining human atrial myocardial resistivity is unknown. In addressing the hypothesis that changing relative expression of Cx40 and Cx43 underlies an increase in human atrial myocardial resistivity with age, this relationship was investigated by direct ex vivo measurement of gap-junctional resistivity and quantitative connexin immunoblotting and immunohistochemistry. Oil-gap impedance measurements were performed to determine resistivity of the intracellular pathway (Ri), which correlated with total Cx40 quantification by Western blotting (rs=0.64, P<0.01, n=20). Specific gap-junctional resistivity (Rj) correlated not only with Western immunoquantification of Cx40 (rs=0.63, P=0.01, n=20), but also more specifically, with the Cx40 fraction localized to the intercalated disks on immunohistochemical quantification (rs=0.66, P=0.02, n=12). Although Cx43 expression showed no correlation with...
Research Interests:
Gap junction resistivity, R(j), has been proposed as a key determinant of conduction velocity (CV). However, studies in connexin-gene knockout mice demonstrated significant CV slowing only with near-complete connexin deletion, and these... more
Gap junction resistivity, R(j), has been proposed as a key determinant of conduction velocity (CV). However, studies in connexin-gene knockout mice demonstrated significant CV slowing only with near-complete connexin deletion, and these findings led to the concept of a significant redundancy of myocardial gap junctions. We challenged this prevailing concept and addressed the hypothesis that there is a continuous relationship between R(j) and CV, each independently measured in human and guinea-pig myocardium. R(j) and CV were directly measured by oil-gap impedance and microelectrode techniques in human left ventricular myocardium from patients with hypertrophic cardiomyopathy and in guinea-pig atrial and ventricular myocardium before and during pharmacological uncoupling with 20-µmol/L carbenoxolone. There was a continuous relationship between R(j) and CV in human and guinea-pig myocardium, pre- and post-carbenoxolone (r(2)=0.946; P<0.01). In guinea-pig left ventricle, left atrium...
Research Interests:
ABSTRACT It is uncertain whether moderate conduction slowing through gap junctional uncoupling on its own, in the absence of action potential or structural changes, is sufficient to be pro-arrhythmic. We used optical mapping: (1) to study... more
ABSTRACT It is uncertain whether moderate conduction slowing through gap junctional uncoupling on its own, in the absence of action potential or structural changes, is sufficient to be pro-arrhythmic. We used optical mapping: (1) to study the effects of carbenoxolone (CBX), a gap junction uncoupler, on conduction velocity and action potential duration and (2) to assess the effects of moderate conduction slowing and gap junctional uncoupling on arrhythmia vulnerability in structurally normal hearts.
Research Interests:
ABSTRACT coupling and action potentials during early reperfusion are thought to contribute to reperfusion arrhythmogenesis. We tested the hypothesis that modulation of gap junctional coupling can reduce the incidence of reperfusion... more
ABSTRACT coupling and action potentials during early reperfusion are thought to contribute to reperfusion arrhythmogenesis. We tested the hypothesis that modulation of gap junctional coupling can reduce the incidence of reperfusion arrhythmias and used optical mapping to assess the mechanisms of any antiarrhythmic effect.
Research Interests:
Research Interests:
Page 1. www.SCIENCEPOSTERS.co.uk Atrial fibrillation-induced Connexin 43 redistribution in atria of the Goat Chowdhury R, Dhillon P, Kaba R, Hall MC*, Kirubakaran S*, Garratt CJ* and Peters NS Imperial College London, UK, *Manchester... more
Page 1. www.SCIENCEPOSTERS.co.uk Atrial fibrillation-induced Connexin 43 redistribution in atria of the Goat Chowdhury R, Dhillon P, Kaba R, Hall MC*, Kirubakaran S*, Garratt CJ* and Peters NS Imperial College London, UK, *Manchester Heart Centre, Manchester, UK ...