A novel method of measuring nitric-oxide-dependent fluorescence using 4,5-diaminofluorescein (DAF-2) in the isolated Langendorff-perfused rabbit heart

Patel, Vipulkumar Ishvarbhai; Brack, Kieran E.; Coote, John H.; Ng, Guseva

doi:10.1007/s00424-007-0440-y

Cited by 21 publications

(21 citation statements)

References 37 publications

(42 reference statements)

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“…Researchers in our laboratory (Patel et al 2008) and other groups (Stowe et al 1997) have previously demonstrated that the uncoupling agent 2,3‐butanedione monoxime has a significant vasodilatory action that contrasts with the effects of blebbistatin seen in the present study. It is, however, recognized that 2,3‐butanedione monoxime has additional metabolic effects.…”

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confidence: 64%

The mechanical uncoupler blebbistatin is associated with significant electrophysiological effects in the isolated rabbit heart

Brack

Narang

Winter

et al. 2013

Experimental Physiology

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Blebbistatin (BS) is a recently discovered inhibitor of the myosin II isoform and has been adopted as the mechanical uncoupler of choice for optical mapping, because previous studies suggest that BS has no significant cardiac electrophysiological effects in a number of species. The aim of this study was to determine whether BS affects cardiac electrophysiology in isolated New Zealand White rabbit hearts. Langendorff-perfused hearts (n= 39) in constant-flow mode had left ventricular monophasic action potential duration (MAPD) measured at apical and basal regions during constant pacing (300 ms cycle length). Standard action potential duration restitution was obtained using the single extrastimulus method with measurement of the maximal restitution slope. Ventricular fibrillation threshold was measured as the minimal current inducing sustained ventricular fibrillation with burst pacing (30 stimuli, at 30 ms intervals). Optical action potentials were recorded using the voltage-sensitive dye di-4-ANEPPS. Measurements were taken at baseline and after 60 min perfusion with BS (5 μm). Blebbistatin significantly prolonged left ventricular apical (mean ± SEM; from 129.9 ± 2.9 to 170.7 ± 4.1 ms, P < 0.001, n= 8) and basal MAPD (from 135.0 ± 2.3 to 163.3 ± 5.6 ms, P < 0.001) and effective refractory period (from 141.3 ± 4.8 to 175.6 ± 3.7 ms, P < 0.001) whilst increasing the maximal slope of restitution (apex, from 0.79 ± 0.09 to 1.57 ± 0.16, P < 0.001; and base, from 0.71 ± 0.06 to 1.44 ± 0.24, P < 0.001) and ventricular fibrillation threshold (from 5.3 ± 1.1 to 17.0 ± 2.9 mA, P < 0.001). In other hearts, blebbistatin significantly prolonged optically recorded action potentials (from 136.5 ± 6.3 to 173.0 ± 7.9 ms, P < 0.05, n= 4). In control experiments, the increase of MAPD with blebbistatin was present whether the hearts were perfused in constant-pressure mode (n= 5) or in unloaded conditions (n= 5). These data show that blebbistatin significantly affects cardiac electrophysiology. Its use in optical mapping studies should be treated with caution.

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confidence: 64%

The mechanical uncoupler blebbistatin is associated with significant electrophysiological effects in the isolated rabbit heart

Brack

Narang

Winter

et al. 2013

Experimental Physiology

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“…The DAF probes show no fluorescence in the presence of common interferents for NO such as NO 2 − , NO 3 − , hydrogen peroxide (H 2 O 2 ), and peroxynitrite (ONOO − ), and have a detection limit as low as 5 nM (63). Examples of using DAF probes include quantifying changes in NO production in stimulated perfused rabbit hearts (64) and imaging NO production in living zebrafish (65). …”

Section: Spectroscopic Methodsmentioning

confidence: 99%

Analytical Chemistry of Nitric Oxide

Hetrick

Schoenfisch

2009

Annual Rev. Anal. Chem.

271

277

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Nitric oxide (NO) is the focus of intense research, owing primarily to its wide-ranging biological and physiological actions. A requirement for understanding its origin, activity, and regulation is the need for accurate and precise measurement techniques. Unfortunately, analytical assays for monitoring NO are challenged by NO’s unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life. Moreover, NO concentrations may span pM to µM in physiological milieu, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. Herein, we review the most common spectroscopic and electrochemical methods, with special focus on the fundamentals behind each technique and approaches that have been coupled with modern analytical measurement tools or exploited to create novel NO sensors.

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“…However, the experiments provided only indirect evidence. Through use of the NO‐sensitive dye DAF‐2 DA, we developed a novel fluorescence technique for measuring NO in the whole heart and were able to provide direct evidence of NO release in the ventricle resulting from vagus nerve stimulation (Patel et al ). Nitric oxide‐dependent fluorescence increased during both left and right cervical vagus nerve stimulation with the intensity of stimulation.…”

Section: Sudden Cardiac Death and The Autonomic Nervous Systemmentioning

confidence: 99%

Vagal modulation of cardiac ventricular arrhythmia

2013

Experimental Physiology

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New findings r What is the topic of this review?This article addresses the relationship between vagus nerve activity and malignant ventricular arrhythmias. It focuses on the clinical association of an impaired vagal tone in cardiac disease states with high mortality from sudden cardiac death and the potential underlying mechanisms. r What advances does it highlight?The article summarizes the mounting evidence that vagal innervation in the cardiac ventricle plays a key direct role in the prevention of the initiation of ventricular fibrillation. Data are presented on the role that nitric oxide plays in mediating the effects of vagal protection against ventricular fibrillation, supporting the notion that a separate non-muscarinic, nitrergic population of vagal neurons is responsible for this protection.

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A novel method of measuring nitric-oxide-dependent fluorescence using 4,5-diaminofluorescein (DAF-2) in the isolated Langendorff-perfused rabbit heart

Cited by 21 publications

References 37 publications

The mechanical uncoupler blebbistatin is associated with significant electrophysiological effects in the isolated rabbit heart

The mechanical uncoupler blebbistatin is associated with significant electrophysiological effects in the isolated rabbit heart

Analytical Chemistry of Nitric Oxide

Vagal modulation of cardiac ventricular arrhythmia

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