The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Toshio Ichikawa - One of the best experts on this subject based on the ideXlab platform.
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partial synchronization dynamics of coupled ultradian oscillators comprising an insect Neurosecretory Cell system
Zoological Science, 2009Co-Authors: Toshio IchikawaAbstract:An insulin-related peptide, bombyxin, in the silkmoth Bombyx mori is secreted by four pairs of cerebral Neurosecretory Cells that form a weakly coupled oscillator system to produce a pulsatile pattern of hormone secretion. The activity of individual bombyxin-producing (BP) Cells oscillated with different periods (20–70 min). The population of BP Cells exhibited complex phase dynamics, including spontaneous synchronization and desynchronization of different combinations of Cells. Statistical cross-correlation analyses of oscillation patterns between BP Cells revealed that one Cell usually correlated closely with a few particular Cells of similar periodicity. Close investigation of the phase differences between individual active phases of the related Cell pairs revealed that an inphase synchronous state was usually maintained for many cycles, whereas an antiphase state was transient, lasting for a few cycles. In contrast, antiphase synchronous states often occurred between several Cell pairs when the brain containing the cerebral Neurosecretory Cell system was disconnected from the ventral nerve cord containing the neuronal mechanism that induced periodic heartbeat reversals at intervals of 80–110 min and exerted a periodic suppressive or phase-resetting effect on individual BP Cells. These results suggest that the internal coupling mechanism in the BP Cell system is not sufficient to maintain an in-phase synchronous state in the heterogeneous Cell population, and that the external phase resetting mechanism may assist in-phase synchronization of many Neurosecretory Cells to generate an overall pulsatile pattern of bombyxin secretion.
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synchronous firing dynamics in a heterogeneous Neurosecretory Cell population in an insect
Brain Research, 2002Co-Authors: Toshio IchikawaAbstract:Five pairs of Neurosecretory Cells in the subesophageal ganglion of the silkmoth Bombyx mori discharge action potentials in (near) synchrony to release a pheromone biosynthesis-activating neuropeptide (PBAN). Waveforms of compound action potentials recorded extraCellularly from axonal tracts were analyzed to determine the firing activity, timing of spikes and the combination of active Cells. Analyses revealed a heterogeneous Cellular organization of the Neurosecretory Cell system. There was a gradient in the firing activity among the Cells and the activity of a Cell was closely related to relative timing of firing: the most active Cell was usually the first to fire and participated in about 90% of all synchronous firing events, while the least active unit was mostly the last to fire and contributed to only 40% of all firing events. A Cell with a higher firing activity had a higher potential to mediate propagation of synchronous firing in the Cell system. Firing activities of right and left Cell groups usually differed and the difference increased in case of a low temperature. Synchronous firings occurred more frequently among the same subgroup of Cells rather than different subgroups. Heterogeneous Cellular organization and coupling may be important for producing a graded pattern of active Cell numbers, which seems to be suitable for maintaining a stable firing (secretory) activity of the Cell system for a long period of time.
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Synchronous firing patterns of a set of insect Neurosecretory Cells.
Neuroscience Letters, 1999Co-Authors: Toshio Ichikawa, Yasuhiro Imafuku, Katsuhisa TawadaAbstract:The number of active Cells in each synchronous firing event in a set of 10 Neurosecretory Cells in the silkmoth Bombyx mori was estimated from the amplitude and waveform of compound action potentials. One to 10 Cells discharged an action potential within a period of 30 ms and one to two or nine to 10 units became active more frequently in a synchronous firing event. Numbers of active Cells fluctuated like a sequence of pseudo random numbers, though the same number of Cells tended to fire in two successive firing events of a short interval. These patterns suggest that electrical coupling may mediate synchronous firings in the insect Neurosecretory Cell system.
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functional differentiation of Neurosecretory Cells with immunoreactive diapause hormone and pheromone biosynthesis activating neuropeptide of the moth bombyx mori
Zoological Science, 1996Co-Authors: Toshio Ichikawa, Tomomi Shiota, Isamu Shimizu, Hiroshi KataokaAbstract:Abstract The suboesophageal ganglion of the silkworm, Bombyx mori, contains three clusters of Neurosecretory Cells that are imrnunoreactive with antisera against the diapause hormone (DH) and the pheromone biosynthesis-activating neuropeptide (PBAN), the two neurohormones that are generated from a common precursor protein. The Cells lie on the ventral midline of the ganglion. Neurosecretory Cell clusters responsible for the diapause induction activity and the pheromonotropic activity of females were determined by surgically removing one or two of the three clusters of the DH/ PBAN imrnunoreactive Cells. A potent diapause induction activity was obtained in females retaining a posterior cluster of Cells while a strong pheromonotropic activity was obtained in case of females with a medial cluster. The functional differentiation of these Cells may relate to different biochemical and/or physiological natures.
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architecture of cerebral Neurosecretory Cell systems in the silkworm bombyx mori
The Journal of Experimental Biology, 1991Co-Authors: Toshio IchikawaAbstract:Anatomical and physiological characteristics of putative Neurosecretory Cells (NSCs) in the medial and lateral areas of the larval brain of Bombyx mori , identifiable by the opalescent appearance of their somata, were examined by means of intraCellular recording and staining. IntraCellular injection of Lucifer Yellow revealed that the medial Cell group consisted of at least six subgroups of Cells distinguishable by the geometry of their dendritic branches. Five subgroups of Cells project axons to the contralateral corpus allatum (CA) or to the corpus cardiacum (CC). The remaining subgroup sends an axon to the ipsilateral ventral nerve cord. Three subgroups of Cells were identified in the lateral group, projecting axons to the ipsilateral CC, to the CA or to the contralateral CA. Large and prolonged action potentials, similar to those recorded in some Neurosecretory systems, were recorded from these medial and lateral Cells. However, two pairs of medial Cells containing paraldehyde-fuchsin-positive (Neurosecretory) material and with axons extending to the contralateral nerve cord had action potentials of a short duration, more typical of non-NSCs such as tritocerebral Cells innervating the stomodeal dilator muscles via the CC.
David Murphy - One of the best experts on this subject based on the ideXlab platform.
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Transgenic and Transcriptional Studies on Neurosecretory Cell Gene Expression
Cellular and Molecular Neurobiology, 1998Co-Authors: Sarah Jane Waller, Anil Ratty, J. Peter H. Burbach, David MurphyAbstract:1. Studies of the regulation of Neurosecretory Cell gene expression suffer from the lack of suitable Cell lines. Two approaches have been used to overcome this deficit: transfection of neuropeptide genes into heterologous Cell lines and generation of transgenic animals. 2. Studies with heterologous Cell lines have revealed the potential involvement of nuclear hormone receptors, POU proteins, and fos/jun/ATF family members in the regulation of the vasopressin and oxytocin genes. Although limited in their scope, these studies have contributed greatly to the dissection of basic properties of elements in the vasopressin and oxytocin gene promoters. 3. Transgenic mice, and more recently rats, have been used to elucidate genomic regions governing Cell specificity and physiological regulation of Neurosecretory gene expression. The genes encoding the neuropeptides vasopressin and oxytocin have been used in many transgenic studies, due to the well-defined expression patterns and physiology of the endogenous neuropeptides. Cell-specific and physiologically regulated expression of these transgenes has been achieved, demonstrating the action of putative represser elements and regulation of the expression of one gene by sequences present in the other gene. 4. Appropriate expression and translation of transgenes have resulted in the production of several useful systems. Expression of oncogene sequences in gonadotropin-releasing hormone neurons has allowed the development of Cell lines from the resulting tumors, overproduction of corticotropin-releasing factor has produced animal models of anxiety and obesity, and directed ectopic expression of growth hormone has generated a potentially useful rat model of dwarfism. These and other animal models of human disease will provide important avenues for the development of therapeutic strategies.
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Transgenic and transcriptional studies on Neurosecretory Cell gene expression
Cellular and molecular neurobiology, 1998Co-Authors: S Waller, Anil Ratty, J. Peter H. Burbach, David MurphyAbstract:1. Studies of the regulation of Neurosecretory Cell gene expression suffer from the lack of suitable Cell lines. Two approaches have been used to overcome this deficit: transfection of neuropeptide genes into heterologous Cell lines and generation of transgenic animals.
Anil Ratty - One of the best experts on this subject based on the ideXlab platform.
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Transgenic and Transcriptional Studies on Neurosecretory Cell Gene Expression
Cellular and Molecular Neurobiology, 1998Co-Authors: Sarah Jane Waller, Anil Ratty, J. Peter H. Burbach, David MurphyAbstract:1. Studies of the regulation of Neurosecretory Cell gene expression suffer from the lack of suitable Cell lines. Two approaches have been used to overcome this deficit: transfection of neuropeptide genes into heterologous Cell lines and generation of transgenic animals. 2. Studies with heterologous Cell lines have revealed the potential involvement of nuclear hormone receptors, POU proteins, and fos/jun/ATF family members in the regulation of the vasopressin and oxytocin genes. Although limited in their scope, these studies have contributed greatly to the dissection of basic properties of elements in the vasopressin and oxytocin gene promoters. 3. Transgenic mice, and more recently rats, have been used to elucidate genomic regions governing Cell specificity and physiological regulation of Neurosecretory gene expression. The genes encoding the neuropeptides vasopressin and oxytocin have been used in many transgenic studies, due to the well-defined expression patterns and physiology of the endogenous neuropeptides. Cell-specific and physiologically regulated expression of these transgenes has been achieved, demonstrating the action of putative represser elements and regulation of the expression of one gene by sequences present in the other gene. 4. Appropriate expression and translation of transgenes have resulted in the production of several useful systems. Expression of oncogene sequences in gonadotropin-releasing hormone neurons has allowed the development of Cell lines from the resulting tumors, overproduction of corticotropin-releasing factor has produced animal models of anxiety and obesity, and directed ectopic expression of growth hormone has generated a potentially useful rat model of dwarfism. These and other animal models of human disease will provide important avenues for the development of therapeutic strategies.
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Transgenic and transcriptional studies on Neurosecretory Cell gene expression
Cellular and molecular neurobiology, 1998Co-Authors: S Waller, Anil Ratty, J. Peter H. Burbach, David MurphyAbstract:1. Studies of the regulation of Neurosecretory Cell gene expression suffer from the lack of suitable Cell lines. Two approaches have been used to overcome this deficit: transfection of neuropeptide genes into heterologous Cell lines and generation of transgenic animals.
J. Peter H. Burbach - One of the best experts on this subject based on the ideXlab platform.
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Transgenic and Transcriptional Studies on Neurosecretory Cell Gene Expression
Cellular and Molecular Neurobiology, 1998Co-Authors: Sarah Jane Waller, Anil Ratty, J. Peter H. Burbach, David MurphyAbstract:1. Studies of the regulation of Neurosecretory Cell gene expression suffer from the lack of suitable Cell lines. Two approaches have been used to overcome this deficit: transfection of neuropeptide genes into heterologous Cell lines and generation of transgenic animals. 2. Studies with heterologous Cell lines have revealed the potential involvement of nuclear hormone receptors, POU proteins, and fos/jun/ATF family members in the regulation of the vasopressin and oxytocin genes. Although limited in their scope, these studies have contributed greatly to the dissection of basic properties of elements in the vasopressin and oxytocin gene promoters. 3. Transgenic mice, and more recently rats, have been used to elucidate genomic regions governing Cell specificity and physiological regulation of Neurosecretory gene expression. The genes encoding the neuropeptides vasopressin and oxytocin have been used in many transgenic studies, due to the well-defined expression patterns and physiology of the endogenous neuropeptides. Cell-specific and physiologically regulated expression of these transgenes has been achieved, demonstrating the action of putative represser elements and regulation of the expression of one gene by sequences present in the other gene. 4. Appropriate expression and translation of transgenes have resulted in the production of several useful systems. Expression of oncogene sequences in gonadotropin-releasing hormone neurons has allowed the development of Cell lines from the resulting tumors, overproduction of corticotropin-releasing factor has produced animal models of anxiety and obesity, and directed ectopic expression of growth hormone has generated a potentially useful rat model of dwarfism. These and other animal models of human disease will provide important avenues for the development of therapeutic strategies.
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Transgenic and transcriptional studies on Neurosecretory Cell gene expression
Cellular and molecular neurobiology, 1998Co-Authors: S Waller, Anil Ratty, J. Peter H. Burbach, David MurphyAbstract:1. Studies of the regulation of Neurosecretory Cell gene expression suffer from the lack of suitable Cell lines. Two approaches have been used to overcome this deficit: transfection of neuropeptide genes into heterologous Cell lines and generation of transgenic animals.
David W. Smith - One of the best experts on this subject based on the ideXlab platform.
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c-Fos expression in hypothalamic Neurosecretory and brainstem catecholamine Cells following noxious somatic stimuli
Neuroscience, 1994Co-Authors: David W. SmithAbstract:Noxious somatic stimuli elicit vasopressin secretion, an effect thought to result from activation of a facilitatory input from A1 catecholamine Cells of the medulla oblongata. To better characterize the A1 Cell response and effects on other neuroendocrine A1 projection targets, particularly within the paraventricular nucleus, we have now mapped c-fos expression in neurochemically identified catecholamine and Neurosecretory Cells following a noxious somatic stimulus. Unilateral hind paw pinch significantly increased c-fos expression in contralateral A1 Cells whereas other brainstem catecholamine Cell groups were unaffected. Expression of c-fos was also increased in the supraoptic nucleus, this effect being more pronounced for vasopressin than oxytocin Neurosecretory Cells and, as with A1 Cells, primarily on the side contralateral to the stimulated paw. In contrast, the increase in the paraventricular nucleus was greater in oxytocin rather than in vasopressin Cells. Additionally there was a significant rise in c-fos expression in medial parvoCellular paraventricular nucleus Cells of noxiously stimulated animals. Notably, the majority of tuberoinfundibular corticotropin-releasing factor Cells are located in this medial parvoCellular zone. These results are consistent with and expand on those previously reported from electrophysiological and anatomical studies. The finding of differing Neurosecretory Cell responses between supraoptic and paraventricular nuclei has interesting implications with regard to the afferent control of Neurosecretory Cell activity. For example, the substantially greater activation of supraoptic versus paraventricular nucleus vasopressin Cells, despite being innervated by the same medullary noradrenergic Cell group, raises the possibility of a differential input or differences in responsiveness. Furthermore, the activation of paraventricular nucleus parvoCellular Cells is consistent with suggestions that the A1 Cell group provides an excitatory input to this population.
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c fos expression in hypothalamic Neurosecretory and brainstem catecholamine Cells following noxious somatic stimuli
Neuroscience, 1994Co-Authors: David W. Smith, Trevor A DayAbstract:Noxious somatic stimuli elicit vasopressin secretion, an effect thought to result from activation of a facilitatory input from A1 catecholamine Cells of the medulla oblongata. To better characterize the A1 Cell response and effects on other neuroendocrine A1 projection targets, particularly within the paraventricular nucleus, we have now mapped c-fos expression in neurochemically identified catecholamine and Neurosecretory Cells following a noxious somatic stimulus. Unilateral hind paw pinch significantly increased c-fos expression in contralateral A1 Cells whereas other brainstem catecholamine Cell groups were unaffected. Expression of c-fos was also increased in the supraoptic nucleus, this effect being more pronounced for vasopressin than oxytocin Neurosecretory Cells and, as with A1 Cells, primarily on the side contralateral to the stimulated paw. In contrast, the increase in the paraventricular nucleus was greater in oxytocin rather than in vasopressin Cells. Additionally there was a significant rise in c-fos expression in medial parvoCellular paraventricular nucleus Cells of noxiously stimulated animals. Notably, the majority of tuberoinfundibular corticotropin-releasing factor Cells are located in this medial parvoCellular zone. These results are consistent with and expand on those previously reported from electrophysiological and anatomical studies. The finding of differing Neurosecretory Cell responses between supraoptic and paraventricular nuclei has interesting implications with regard to the afferent control of Neurosecretory Cell activity. For example, the substantially greater activation of supraoptic versus paraventricular nucleus vasopressin Cells, despite being innervated by the same medullary noradrenergic Cell group, raises the possibility of a differential input or differences in responsiveness. Furthermore, the activation of paraventricular nucleus parvoCellular Cells is consistent with suggestions that the A1 Cell group provides an excitatory input to this population.