Regional gradient of pacemaker activity in the early embryonic chick heart monitored by multisite optical recording.

Kamino, Kohtaro; Komuro, Hitoshi; Sakai, Tetsuro

doi:10.1113/jphysiol.1988.sp017205

Cited by 9 publications

(9 citation statements)

References 23 publications

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“…Using this multiple-site optical recording method, we have studied electrophysiological organization in the early embryonic heart for several years (Komuro, Hirota, Yada, Sakai, Fujii & Kamino, 1985; Hirota, Kamino, Komuro, Sakai & Yada, 1985a, b;Hirota, Kamino, Komuro & Sakai, 1987; Kamino, Komuro, Sakai & Hirota, 1988c; Kamino, Komuro & Sakai, 1988b), and throughout these experiments we have also attended to the problem of the early developmental organization of the cardiovascular nervous control system, and we have noted that the multiplesite optical recording method would be useful for analysing the functional organization in the early embryonic central nervous system.…”

Section: Introductionmentioning

confidence: 99%

Multiple‐site optical monitoring of neural activity evoked by vagus nerve stimulation in the embryonic chick brain stem.

Kamino

Kato

Komuro

et al. 1989

The Journal of Physiology

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SUMMARY1. Electrical activity in the embryonic chick brain stem has been monitored optically. The vagus-brain stem preparations isolated from 7-day-old chick embryos were stained with voltage-sensitive merocyanine-rhodanine dyes.2. Voltage-related optical absorption signals evoked by vagus nerve stimulation with depolarizing and hyperpolarizing pulses using a suction electrode were recorded simultaneously from 127 adjacent loci in the brain stem using a 12 x 12-element photodiode array.3. The optical signals evoked by the stimulation appeared to be concentrated longitudinally in the central region and in the lateral region, both on the stimulated side of the brain stem, and they did not spread to the opposite side. In addition, the evoked optical responses were detected from small areas on the dorsal surface of the stimulated side, in experiments using transverse slices of brain stem. 4. The optical action potential signals evoked by the brief depolarizing stimulus were conducted slowly and were blocked completely by tetrodotoxin. With relatively long-duration depolarizing and hyperpolarizing stimulations, electrotonic responses were recorded. 5. When 2 1sA/2 ms hyperpolarizing pulse stimulations were applied, anode-break excitation signals were detected, and these signals were also blocked by tetrodotoxin.6. On the basis of the data obtained from these experiments, we constructed maps of the electrical response area and demonstrated the spatial pattern of the vagus dorsal nucleus in the 7-day-old embryonic chick brain stem.

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Section: Introductionmentioning

confidence: 99%

Multiple‐site optical monitoring of neural activity evoked by vagus nerve stimulation in the embryonic chick brain stem.

Kamino

Kato

Komuro

et al. 1989

The Journal of Physiology

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“…Unfortunately, in the quadruple-hearted preparations, since we could detect action potential signals from only a small number of regions (at most six) in one segmented heart, it was not feasible to assess accurately the pacemaking area and the conduction pattern with the graphical method we have used previously [15,16]. Nevertheless, the delays in the firing time of the optical action signals suggest that the conduction velocities in the segmented hearts were about 3-4 mm/s in this preparation.…”

Section: Pacemaking Areamentioning

confidence: 99%

“…On the basis of these findings, we have proposed that, during the early phases of cardiogenesis, the formation of a regional gradient of pacemaker activity (i.e. a spatial gradient of intrinsic rhythmicity) results in the functional organization of the pacemaking area [14][15][16]24].…”

Section: Introductionmentioning

confidence: 97%

A regional gradient of cardiac intrinsic rhythmicity depicted in embryonic cultured multiple hearts

Sakai¹,

Yada²,

Hirota³

et al. 1998

Pfl�gers Archiv European Journal of Physiology

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We used optical methods to examine the spatial gradient of intrinsic rhythmicity in early-stage multiple-heart chick embryos. The latter were induced experimentally in whole-embryo culture. The embryos were cut microsurgically through the tissue of the anterior intestinal portal at the 5- to early 7-somite developmental stage. Spontaneous electrical activity in 4 to 6 segmented hearts, during the 7- to 10-somite stages of development, were monitored simultaneously by means of multiple-site optical recordings of membrane potential activity, using a voltage-sensitive merocyanine-rhodanine dye (NK2761). Each segment of the heart exhibited its own inherent rhythmicity. In quadruple hearts, the order of the rhythmicity was often left-caudal segment>right-caudal segment>left-cephalic segment>right-cephalic segment; the heart rate in the left-caudal segment was often faster than that in the other segments. An atypical pattern of "bursting" rhythm was observed in the cephalic segments suggesting that, in these segments, the development of rhythmicity is relatively poor. These findings strongly emphasize the concept that, in the early phases of cardiogenesis, the formation of a regional gradient of pacemaker activity (i.e. a spatial gradient of intrinsic rhythmicity) results in the functional self-organization of the pacemaking area.

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“…We suggest that the pacemaking area comprises 60-150 cells and that the pacemaking area remains at a nearly constant size throughout the 7-to 9-somite stages. It is thus proposed that a population of pacemaking cells, instead of a single cell, serves as a rhythm generator in the embryonic chick heart [46-48, 87,88].…”

Section: Early Embryonic Heartsmentioning

confidence: 99%

Optical Mapping Approaches to Cardiac Electrophysiological Functions.

Sakai

Kamino²

2001

JJP

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Electrophysiology has been one of the most important strategies in cardiac physiology since the mid19th century [1]. The methodology in this field has been improved with the development of electronics, and quite sophisticated techniques using extracellular electrodes, intracellular microelectrodes, and patch electrodes are now widely used. Recently, optical methods for monitoring membrane potential with fast voltage-sensitive dyes were introduced as a new powerful tool for studying cardiac electrical functions. In this article, optical studies of the electrophysiological function of the vertebrate heart are reviewed. HISTORICAL BACKGROUND OF OPTICAL METHODS FOR MONITORING ELECTRICAL ACTIVITYIn 1968, changes in intrinsic light scattering, in birefringence, and in extrinsic 8-anilino-naphtalene-1-sulfonate (ANS) fluorescence associated with an action potential in the squid giant axon were first reported by Cohen et al. [2] and by Tasaki et al. [3]. At first these experiments were carried out to learn about conformation and/or structural changes that might occur during nerve excitation: it was hoped that the observed optical changes might be related to some molecular mechanism(s) of electrical excitation [4]. In additional experiments, however, Cohen, Salzberg, and co-workers indicated that fluorescent changes depended on changes in transmembrane potential [5], and they soon suggested that optical methods might be used for monitoring membrane potential in cells or cellular processes not accessible to microelectrodes [6,7]. Key words: voltage-sensitive dye, optical recording, electrical activity, heart. Abstract:Recently, optical methods for monitoring membrane potential with fast voltage-sensitive dyes have been introduced as a powerful tool for studying cardiac electrical functions. These methods offer two principal advantages over more conventional electrophysiological techniques. One is that optical recordings may be made from very small cells that are inaccessible to microelectrode impalement, and the other is that multiple sites/regions of a preparation can be monitored simultaneously to provide spatially resolved mapping of electrical activity. The former has made it possible to record spontaneous electrical activities in early embryonic precontractile hearts, and the latter has been applied for mapping of the propagation patterns of electrical activities in the cardiac tissue. In this article, optical studies of the electrophysiological function of the vertebrate heart are reviewed.

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Regional gradient of pacemaker activity in the early embryonic chick heart monitored by multisite optical recording.

Cited by 9 publications

References 23 publications

Multiple‐site optical monitoring of neural activity evoked by vagus nerve stimulation in the embryonic chick brain stem.

Multiple‐site optical monitoring of neural activity evoked by vagus nerve stimulation in the embryonic chick brain stem.

A regional gradient of cardiac intrinsic rhythmicity depicted in embryonic cultured multiple hearts

Optical Mapping Approaches to Cardiac Electrophysiological Functions.

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