Temperature dependence of spontaneous electrical activity in early embryonic heart monitored optically with a potential-sensitive dye.

Hirota, Akihiko; Fujii, Soichiro; Sakai, Tetsuro; Kamino, Kohtaro

doi:10.2170/jjphysiol.33.85

Cited by 15 publications

(8 citation statements)

References 13 publications

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“…Excitations which originate in the pace-making area spread over the entire region of the embryonic heart. We have already found, in the 8-somite embryonic precontractile chick heart, 'switching phenomena'; the site exhibiting pace-making priority was first situated in the right pre-atrium, and then switched over to the left pre-atrium, or vice versa (Sakai, Hirota, Fujii & Kamino, 1983b). Similar phenomena also were often observed in the embryonic rat heart.…”

Section: Resultssupporting

confidence: 68%

“…Thus, our present findings strongly suggest that conventional ideas concerning the onset of contraction of the embryonic rat heart need to be corrected. Hirota et al 1983b, measured in the 7-9 somite preheating hearts at 368-37-4 'C; * §, Hirota et al 1983a; ¶, Fujii et al 1980;11, Hirota et al 1985. We have indicated earlier (Fujii et al 1981 a) one element of a photodiode array detects signals from many active cells at once in a multicellular tissue (Senseman & Salzberg, 1980). We may thus assume that the observed size of the optical signals is a function of the active membrane area and of the optical signal generated by a unit area of active membrane undergoing an action potential.…”

Section: Discussionmentioning

confidence: 99%

“…Procedures for thermo-regulation were as described previously (Hirota, Fujii, Sakai & Kamino, 1983b). The temperature of the bathing solution in the chamber was controlled by means of a thermo-regulator fixed to the stage of the microscope used for the optical measurements.…”

Section: Optical Measurementmentioning

confidence: 99%

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Early events in development of electrical activity and contraction in embryonic rat heart assessed by optical recording.

Hirota¹,

Kamino²,

Komuro³

et al. 1985

The Journal of Physiology

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SUMMARY1. Spontaneous action potential and contraction in the early embryonic heart ofthe rat have been monitored optically using a voltage-sensitive merocyanine-rhodanine dye together with a multiple-element photodiode matrix array, and the onset of rhythmical action-potential activity in the early phases of rat cardiogenesis was conclusively determined for the first time.2. Spontaneous rhythmical action potentials were first generated in the central part of the embryonic heart at the middle period ofthe 3-somite stage ofdevelopment, at 92 days after copulation. Subsequently, contractions coupled with the action potential also appeared at the end of the 3-somite stage.3. Usually, at the 3-somite stage, spontaneous action signals were synchronized among the different areas in the heart. From this result, it is evident that the paired right and left cardiac primordia are fused completely at the time of initiation of spontaneous electrical activity.4. In the 3-somite embryonic heart, excitatory waves were conducted radially over the heart, at a uniform rate (0-4-0-8 mm/s), from the pace-making area. However, the regional priority of pace-making activity is not rigid but is flexible.

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Section: Resultssupporting

confidence: 68%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Early events in development of electrical activity and contraction in embryonic rat heart assessed by optical recording.

Hirota¹,

Kamino²,

Komuro³

et al. 1985

The Journal of Physiology

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“…Furthermore, we demonstrated that in the adult frog atrial preparation stained with a merocyanine-rhodanine dye (NK 2761) the time course and shape of the absorption change are very similar to the action potential recorded using a microelectrode, under conditions where contraction was reduced in a Ca2+-free bathing solution, and that absorption change accurately reflects phases 0, 1, 2, 3 and 4 in an action potential (Appendix in Hirota et al 1983). Similar results were obtained from the experiments on 5-and 8-day-old embryonic chick hearts (Fujii, Hirota & Kamino, 1980.…”

Section: Discussionmentioning

confidence: 86%

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

Kamino

Komuro

Sakai

1988

The Journal of Physiology

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SUMMARY1. Regional gradient of pacemaker activity in the early embryonic precontractile chick heart was quantitatively assessed by means of simultaneous multiple-site optical recordings of changes in membrane potential, using a measuring system with a 10 x 10-element photodiode array which had a spatial resolution of 30 ,um.2. Absorption changes related to spontaneous electrical activity were recorded simultaneously from many contiguous regions in the area in which the pacemaker site was located in seven-to nine-somite embryonic hearts stained with a voltagesensitive merocyanine-rhodanine dye (NK 2761).3. The absorption changes related to slow diastolic depolarization were detected, and they were concentrated in and near the pacemaking area. The area in which the absorption changes related to slow diastolic depolarization were detected increased in size as development proceeded.4. The slope of the absorption change related to diastolic depolarization was measured as an indicator of the pacemaker activity. It was largest in the pacemaking area, and gradually decreased towards the periphery.5. The maximum slope of the optical change related to slow diastolic depolarization also increased as development proceeded and was related to early development of the heart rate. Thus, these results suggest that formation of a regional gradient of pacemaker activity results in the functional architecture of the pacemaking area in the early phases of cardiogenesis.

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“…The procedures for thermoregulation were as described previously [8]. The temperature of the bathing solution in the chamber was controlled by means of a thermoregulator fixed to the stage of the microscope used for the optical measurements.…”

Section: Thermoregulationmentioning

confidence: 99%

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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Temperature dependence of spontaneous electrical activity in early embryonic heart monitored optically with a potential-sensitive dye.

Cited by 15 publications

References 13 publications

Early events in development of electrical activity and contraction in embryonic rat heart assessed by optical recording.

Early events in development of electrical activity and contraction in embryonic rat heart assessed by optical recording.

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

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

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