rhodanine and merocyanine-rhodanine

The wavelength dependence of optical action potentials was studied using voltage-sensitive merocyanine-rhodanine, merocyanine-oxazolone, and oxonol dyes in the isolated rat atrium preparation. Most of the dyes had action spectra that were similar to those reported in other preparations. Species-to-species difference was observed with a merocyanine-oxazolone dye.

Topics: Action Potentials; Animals; Atrial Function; Benzenesulfonates; Benzoxazoles; Electric Stimulation; Electrophysiology; Female; Fluorescent Dyes; Heart Atria; Male; Optics and Photonics; Oxazolone; Rats; Rats, Wistar; Rhodanine; Spectrometry, Fluorescence; Thiazolidines

We examined the functional organization of the rat trigeminal nuclear complex and its developmental dynamics using a multiple-site optical recording technique. Brainstem preparations were dissected from embryonic day 12 (E12)-E16 rat embryos, and stimulation was applied individually to the three branches of the trigeminal nerve (V1-V3). The action potential activity of presynaptic fibers was detected from E13, and the glutamate-mediated postsynaptic response was significantly observed from E15 on. At E14, the evoked signals usually consisted of only the action potential-related fast component. However, when extracellular Mg2+ was removed, a significant dl-2-amino-5-phosphonovaleric acid-sensitive slow component appeared. These results suggest that postsynaptic function mediated by NMDA receptors is latently generated as early as E14. The response area of the three branches of the trigeminal nerve showed some functional somatotopic organization, with the ophthalmic (V1) nerve area medially located and the mandibular (V3) nerve area laterally located. The center of the trigeminal nuclear complex in which the activity of neurons and synaptic function was greatest shifted caudally with development, suggesting that the functional architecture of the trigeminal nuclear complex is not fixed but changes dynamically during embryogenesis. By electron microscopy, we could not observe clear correlations between functional data and morphological information; when we surveyed E16 preparations, we could not identify typical synaptic structures between the 1,1'-dioctyldecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled trigeminal nerve terminals and the neurons in the trigeminal nuclear complex. This implies that postsynaptic function in the trigeminal nuclear complex is generated before the appearance of the morphological structure of conventional synapses.

Topics: Animals; Benzoxazoles; Electric Stimulation; Excitatory Amino Acid Antagonists; Excitatory Postsynaptic Potentials; Fluorescent Dyes; Gestational Age; In Vitro Techniques; Magnesium; Mandibular Nerve; Maxillary Nerve; Membrane Potentials; Ophthalmic Nerve; Optics and Photonics; Presynaptic Terminals; Rats; Rats, Wistar; Receptors, Glutamate; Rhodanine; Synaptic Transmission; Thiazolidines; Trigeminal Nerve; Trigeminal Nuclei

The optically recorded action potentials of the frog atrial muscles which lack transverse tubules showed different features from those reported by Heiny and Vergara (Heiny JA, Vergara J. Optical signals from surface and T system membranes in skeletal muscle fibers. J Gen Physiol 1982;80:203-230) in skeletal muscles (Fujishiro N, Kawata H. The wavelength dependence of optically recorded action potentials in the atrial muscles of the bullfrog (Rana catesbeiana). Comp Biochem Physiol 1996;114A:153-157). We examined whether or not the differences were consistent in other atrial muscles which lack transverse tubules with guinea pig atrial muscles. Two dyes (merocyanine rhodanine and merocyanine oxazolone) were used, and the dependence of the maximum rising phase of the optical signals on the wavelength of the incident beam was analyzed. No dependence was observed between them, and this finding was consistent with the structure of the membrane system of the guinea pig atrial muscles. The optical signals recorded at 718 nm of the incident beam from the guinea pig atrial muscles which stained with merocyanine oxazolone showed a more prominent second rising phase after the initial rapid rising phase of the optical signal than that recorded in the frog atrial muscles. This phase was not observed in the optical signals recorded at other wavelengths. The features of the optically recorded action potentials in guinea pig atrial muscles were consistent with those recorded in frog atrial muscles. Nifedipine did not affect the second rising phase.

Topics: Action Potentials; Animals; Atrial Function; Benzoxazoles; Coloring Agents; Guinea Pigs; Heart; In Vitro Techniques; Optics and Photonics; Oxazolone; Rhodanine; Temperature; Thiazolidines

We searched for an optimal voltage-sensitive dye for optical measurements of neural activity in the hippocampal slice by evaluating several merocyanine-rhodanine and oxonol dyes. The wavelength dependence (action spectra), pharmacological effects of staining, signal size, signal-to-noise ratio, and the utility of the dyes for long-term continuous recording were examined for four merocyanine-rhodanine dyes (NK2761, NK2776, NK3224 and NK3225), which had been reported to be optimal in embryonic nervous systems, and for two oxonol dyes (NK3630 (RH482) and NK3041 (RH155)), which have been among the most popular potentiometric probes for the hippocampal slice preparation. NK2761, NK3224 and NK3225 provided large signal-to-noise ratios, and proved to be useful for optical recordings lasting several hours. NK3630 was most suitable for long-term recording, although the signal-to-noise ratio was slightly inferior to that of the merocyanine-rhodanines. Using NK3630 (RH482) on the hippocampal slice preparation, we demonstrate here that long-term potentiation can be monitored stably for more than 8 hr.

Topics: Animals; Barbiturates; Benzoxazoles; Coloring Agents; Electric Conductivity; Electric Stimulation; Excitatory Postsynaptic Potentials; Hippocampus; In Vitro Techniques; Long-Term Potentiation; Male; Optics and Photonics; Rats; Rats, Wistar; Rhodanine; Sensitivity and Specificity; Staining and Labeling; Thiazolidines; Time Factors

To evaluate the suitability of a variety of fast voltage-sensitive dyes for optical recording of rapid transmembrane potential activity in the embryonic nervous system, we screened over twenty dyes, including several newly synthesized probes, in three different embryonic neural preparations: cervical vagus nerve bundle, nodose ganglion, and brainstem from 7-day old chick embryos. Measurements of voltage-related optical signals were made using a multiple-site optical recording system. Signal size, signal-to-noise ratio, photobleaching, and phototoxicity were examined. Several promising new merocyanine-rhodanine dyes for embryonic nervous systems were found.

Topics: Animals; Benzoxazoles; Brain Stem; Cell Membrane; Chick Embryo; Coloring Agents; Evaluation Studies as Topic; Monitoring, Physiologic; Optics and Photonics; Photochemistry; Rhodanine; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Thiazolidines

Using a voltage-sensitive merocyanine-rhodamine dye (NK2761) and a 12 x 12-element photodiode matrix array, we recorded optically spontaneous membrane potential changes in a slice preparation from the embryonic chick brain stem during early development. The spontaneous optical signals, related to membrane potential changes, showed a simple monophasic shape with a relatively long duration, and they were synchronized among the different regions in the medulla oblongata. The spontaneous signals were first detected from seven-day-old embryos, and were not present in six-day-old embryos. The spontaneous signals appeared sporadically, and their frequency was very low. Three modes of optical signals termed "singlet-mode", "doublet-mode", and "triplet-mode" were observed. In the doublet- and triplet-modes, the spatial pattern of the first signal was primarily similar to that of the singlet-mode signal, whereas the signal size and spatial extent of the second and third signals appeared to decay.

Topics: Animals; Benzoxazoles; Brain Stem; Chick Embryo; Histocytochemistry; Medulla Oblongata; Membrane Potentials; Rhodanine; Thiazolidines

Changes in dye absorption and fluorescence produced by electrical stimulation were measured in frog optic nerves stained with voltage-sensitive dyes. Following a single maximal stimulus applied through a suction electrode, the change in transmitted light intensity consisted of two components: one representing an axonal compound action potential and the second a slow depolarizing afterpotential which appeared to arise from the glial cells. The following results support this interpretation: during a train of stimuli the depolarizing potentials sum and can exceed 80% of the initial spike amplitude while the spike amplitude itself remains essentially constant. Thus, the axons cannot have undergone significant depolarization during the train. Optical recordings with simultaneous microelectrode recordings from the glial cells indicate that the change in glial membrane potential during the train has a time-course similar to that of the slow optical response. We conclude that voltage-sensitive dyes can monitor potential changes in both neurons and glia.

Topics: Animals; Axons; Benzoxazoles; Electric Stimulation; Electrophysiology; Microelectrodes; Neuroglia; Optic Nerve; Oxazoles; Oxazolone; Rana pipiens; Rhodanine; Thiazoles; Thiazolidines

Excitation-contraction coupling at the onset of beating in the 9-10-somite embryonic chick heart was studied by means of an optical method together with a voltage-sensitive merocyanine-rhodanine dye. Spontaneous optical signals were recorded simultaneously from many areas of the embryonic heart, using a square photodiode matrix array. At time of initiation of the heartbeat, spontaneous optical signals consisting of two components were often detected. The first component (1st signal) is a dye-related absorption change due to the action potential, and the second component (2nd signal) is a light scattering change due to contraction. When Ca2+ in the bathing solution was partly replaced by Mg2+, the peak size of both signals was reduced. The correlation between the 1st and 2nd signals corresponded to the relationship between excitation and contraction. The formation of excitation-contraction coupling exhibited a regional non-uniformity in the developing 9-10-somite embryonic hearts: contraction was first generated in the right ventricular region, and then the contractile area spread widely over the whole of the heart. The curves of the excitation-related 1st signal vs. the contraction-related 2nd signal obtained from different areas were not superimposable. Decoupling of excitation from contraction was produced by raising the Ca2+ concentration in the bathing solution, by lowering the Na2+ concentration or by inclusion of a Ca2+ ionophore (A23187). Replacement of the bathing solution with D2O or hypertonic solution also suppressed excitation-contraction coupling. The results suggest that in the early embryonic initial beating chick heart, the contractile system is activated by Ca2+ influx across the sarcolemma accompanying the action potential, and that a Na+-Ca2+ exchange mechanism participates in the relaxation phase of the heartbeat.

Topics: Action Potentials; Animals; Benzoxazoles; Calcimycin; Calcium; Chick Embryo; Heart; Magnesium; Myocardial Contraction; Rhodanine; Sodium; Thiazolidines; Time Factors

Circus-movement tachycardia was studied using voltage-sensitive merocyanine-rhodanine dyes (dye XVII and NK2761). Excitatory waves were optically measured simultaneously from eight different regions of a ring of tissue formed from frog atrium. Application of acetylcholine in Ca2+-free solution (10(-10)-10(-9) g/ml) shortened the duration of optical action signals to cause nonuniform change in optical signal durations in about 60% of the preparations. Circus-movement tachycardia was produced by proper reduction and regional nonuniformity of optical signal durations. Under these circumstances it is easy to evoke circus-movement tachycardia by giving an extra stimulus to the site that shows a difference in optical signal durations.

Topics: Acetylcholine; Action Potentials; Animals; Benzoxazoles; Fluorescent Dyes; Heart; Heart Atria; Microelectrodes; Rana catesbeiana; Rhodanine; Tachycardia; Thiazoles; Thiazolidines

The absorption signals of a merocyanine-rhodanine dye in response to action potential were measured on the bullfrog atrium. Simultaneous recording of optical signals and membrane potential showed the same time course within 15 to 30 min after exposure to Ca2+- free solution. The action spectrum of the dye exhibited a triphasic pattern with a decrease in absorption between 530 and 600 nm, an increase between 640 and 720 nm and a decrease at 750 nm. Using five photodetectors we have able to simultaneously monitor the action potential from five different regions of the preparation. The conduction velocity could be measured even in Ca2+- free solution; the velocity measured optically by the simultaneous multi-recording method was equal to that obtained with a microelectrode measurement. Thus, the optical method can validly be used to solve some problems on arrhythmia-related mechanism.

Topics: Action Potentials; Animals; Benzoxazoles; Coloring Agents; Heart; In Vitro Techniques; Methods; Optics and Photonics; Rana catesbeiana; Rhodanine; Thiazoles; Thiazolidines

Changes in light absorption during nerve excitation (absorption responses) were detected from the crab leg nerve, the rabbit vagus, and the rat superior cervical ganglion (SCG) stained with a merocyanine-rhodanine. Dependences of the responses on the wavelength and polarization of the incident light (absorption spectra) showed characteristic features with the respective nerves. In the crab nerve, the pattern of response spectra was precisely analyzed based on the previously proposed scheme, which included the shift of absorption bands and the statistical reorientation of absorption oscillators of the dye molecules in the membrane matrix during nerve excitation. Different patterns of the response spectra between the crab nerve and the rabbit vagus suggested that distinct physicochemical environments of the dye occurred in these two classes of membranes. On the other hand, the characteristic pattern that arose in the rat SCG was explained by its morphological form, that is, unlike those in a bundle of axons, the membrane elements in the ganglion were randomly oriented with respect to the direction of the light polarization.

Topics: Animals; Benzoxazoles; Brachyura; Electric Stimulation; Ganglia, Sympathetic; Light; Nerve Fibers; Rabbits; Rats; Rhodanine; Spectrophotometry; Staining and Labeling; Thiazoles; Thiazolidines; Vagus Nerve

1. Using an optical method for monitoring membrane potential, spontaneous electrical activity in the very early embryonic chick heart at the 7-9 somite stages was measured. 2. Spontaneous absorption signals from the 7-8 somite embryonic chick hearts stained with a potential sensitive merocyanine-oxazolone dye were demonstrated. The signals were observed also when a merocyanine-rhodanine dye was used. These signals were identified as spontaneous electrical activity in the embryonic heart cells. 3. The action spectrum in absorption of the merocyanine-oxazolone dye was triphasic in early embryonic chick heart with an increase in transmittance from 750 to 700, a decrease from 700 to 600, and an increase from 600 to 525 nm. 4. The magnitude of the signal was about 10(-3) of the resting intensity at 675 nm, with the merocyanine-oxazolone dye. The spontaneous absorption signals had a signal-to-noise ratio of about 10, respectively. 5. The absorption signals were markedly depressed by a higher external K+-concentration, however, were not affected by tetrodotoxin (TTX). 6. The results indicate that spontaneous electrical activity is generated at the 7-9 somite developmental stage before the initiation of heartbeat.

Topics: Absorption; Action Potentials; Animals; Benzoxazoles; Chick Embryo; Coloring Agents; Heart; Membrane Potentials; Oxazolone; Rhodanine; Spectrum Analysis; Staining and Labeling; Thiazolidines