Physiology and ultrastructure of electrotonic junctions. IV. Medullary electromotor nuclei in gymnotid fish.

Bennett, M. V.L.; Pappas, George D.; Giménez, Máximo; Nakajima, Yoshiaki

doi:10.1152/jn.1967.30.2.236

Cited by 231 publications

(98 citation statements)

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“…The smaller pacemaker cell type had an average input resistance of 3.7 Ϯ 0.30 M⍀ (n ϭ 10), whereas the larger relay cell type showed an average input resistance of 2.7 Ϯ 0.11 M⍀ (n ϭ 8). This overall range of input resistance in pacemaker and relay cells is consistent with earlier reports in other gymnotiform fish (Bennett et al, 1967;Spiro, 1997).…”

Section: Resultssupporting

confidence: 91%

“…Penetrations of pacemaker and relay cells were achieved by applying brief overcompensation of capacitance neutralization and/or slight mechanical tapping of the head stage of the microdrive. Once the membrane potential of each penetrated cell had stabilized and a steady baseline membrane potential was recorded, cells were characterized physiologically as either pacemaker or relay cells based on action potential wave forms; action potentials in pacemaker cells exhibited gradually depolarizing potentials between spikes that are lacking in relay cells (Bennett et al, 1967;Juranek and Metzner, 1997). After data collection from each cell, a positively biased sinusoidal current (ϳ2.0 nA for 5-10 min) was used to inject neurobiotin into the cell.…”

Section: Methodsmentioning

confidence: 99%

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Segregation of Behavior-Specific Synaptic Inputs to a Vertebrate Neuronal Oscillator

Juranek¹,

Metzner

1998

J. Neurosci.

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Although essential for understanding the mechanisms underlying sensorimotor integration and motor control of behaviors, very little is known about the degree to which different behaviors share neural elements of the sensorimotor command chain by which they are controlled. Here, we provide, to our knowledge, the first direct physiological evidence that various modulatory premotor inputs to a vertebrate central pattern generator, the pacemaker nucleus in gymnotiform electric fish, carrying distinctly different behavioral information, can remain segregated from their various sites of origin in the diencephalon to the synaptic termination sites on different target neurons in the medullary pacemaker nucleus. During pharmacological activation of each of the premotor inputs originating from the three prepacemaker nuclei so far identified, we determined in vivo the changes in input resistance in the neuronal elements of the pacemaker nucleus, i.e., relay cells and pacemaker cells. We found that each input yields significantly different effects on these cells; the inputs from the two diencephalic prepacemaker nuclei, PPnC and PPnG, which resulted in increased oscillator activity, caused significantly lower input resistances in relay and pacemaker cells, respectively, exhibiting drastically different time courses. The input from the sublemniscal prepacemaker nucleus, which resulted in reduced oscillator activity, however, caused a significant increase in input resistance only in relay cells. Considering that the sensory pathways processing stimuli yielding these behaviors are separated as well, this study indicates that sensorimotor control of different behaviors can occur in strictly segregated channels from the sensory input of the brain all through to the synaptic input level of the final premotor command nucleus.

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Section: Resultssupporting

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Segregation of Behavior-Specific Synaptic Inputs to a Vertebrate Neuronal Oscillator

Juranek¹,

Metzner

1998

J. Neurosci.

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“…The cells comprising this neuronal cluster project to relay cells in the Pn where they make glutamatergic synaptic contact involving non-NMDA glutamate receptors (Dye et al 1989). This synaptic input from the CP/PPn-C results in rapid depolarization of the relay cells, which in turn leads to an acceleration of the firing frequency of both the pacemaker cells and the relay cells (Dye 1988), likely due to the extensive gap-junction coupling between these neurons (Bennett et al 1967;Elekes and Szabo 1985;Moortgat et al 2000;Tokunaga et al 1980). Although never examined, it is plausible that the glutamatergic input from the CP/PPn-C to the relay cells of the Pn is much weaker in females than in males.…”

Section: Discussionmentioning

confidence: 99%

Large-scale identification of proteins involved in the development of a sexually dimorphic behavior

Zupanc

Ilieş

Sîrbulescu

et al. 2014

Journal of Neurophysiology

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Zupanc GK, Ilieş I, Sîrbulescu RF, Zupanc MM. Large-scale identification of proteins involved in the development of a sexually dimorphic behavior. J Neurophysiol 111: 1646 -1654, 2014. First published January 29, 2014 doi:10.1152/jn.00750.2013.-Sexually dimorphic behaviors develop under the influence of sex steroids, which induce reversible changes in the underlying neural network of the brain. However, little is known about the proteins that mediate these activational effects of sex steroids. Here, we used a proteomics approach for large-scale identification of proteins involved in the development of a sexually dimorphic behavior, the electric organ discharge of brown ghost knifefish, Apteronotus leptorhynchus. In this weakly electric fish, the discharge frequency is controlled by the medullary pacemaker nucleus and is higher in males than in females. After lowering the discharge frequency by chronic administration of ␤-estradiol, 2-dimensional difference gel electrophoresis revealed 62 proteins spots in tissue samples from the pacemaker nucleus that exhibited significant changes in abundance of Ͼ1.5-fold. The 20 identified protein spots indicated, among others, a potential involvement of astrocytes in the establishment of the behavioral dimorphism. Indeed, immunohistochemical analysis demonstrated higher expression of the astrocytic marker protein GFAP and increased gapjunction coupling between astrocytes in females compared with males. We hypothesize that changes in the size of the glial syncytium, glial coupling, and/or number of glia-specific potassium channels lead to alterations in the firing frequency of the pacemaker nucleus via a mechanism mediating the uptake of extracellular potassium ions from the extracellular space. sexual dimorphism; weakly electric fish; proteomics; neural oscillator; astrocytes SEX DIFFERENCES IN BEHAVIOR are widespread among animals and occur most commonly during social interactions, particularly in the context of courtship and parental care. It is wellestablished that sex steroids play an overarching role in the control of this sexual dimorphism of behavior by influencing the organization of brain structures during development and by inducing reversible changes in neural circuits of the adult brain (Baum 2003;Morris et al. 2004). However, whereas sex differences in brain structures that control specific sexually dimorphic behaviors have been well-characterized (Cooke et al. 1998; Kelley 1988), little is known about the multitude of genes and proteins that regulate these behaviors and mediate the activational effects of sex steroids (Xu et al. 2012). To address this issue, we employed an unbiased, large-scale approach to identify such proteins using the electric organ discharge (EOD) of the weakly electric brown ghost knifefish (Apteronotus leptorhynchus) as a behavioral model that exhibits a reversible sexual dimorphism.In this species, the EOD is produced continuously by synchronous depolarization of modified axonal terminals of spinal electromotor neurons that constitute t...

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“…As shown in Fig.1, the solitary G. omarorum emits sexually monomorphic triphasic electric pulses at around 25Hz at 20°C (Caputi, 1999;Richer-de-Forges et al, 2009), whereas the gregarious B. gauderio emits sexually dimorphic biphasic electric pulses at around 15Hz at 20°C (Hopkins et al, 1990;Caputi et al, 1998). In both species, a medullary pacemaker nucleus (PN) controls the timing of the electric organ discharge (EOD) (Bennett et al, 1967). The spatial organization and innervation pattern of the peripheral electric organ are responsible for the species-specific EOD waveform (TrujilloCenóz et al, 1984;Stoddard, 2002).…”

Section: Introductionmentioning

confidence: 99%

Neuromodulation of the agonistic behavior in two species of weakly electric fish that display different types of aggression

Silva

Perrone

Zubizarreta

et al. 2013

Journal of Experimental Biology

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SummaryAgonistic behavior has shaped sociality across evolution. Though extremely diverse in types of displays and timing, agonistic encounters always follow the same conserved phases (evaluation, contest and post-resolution) and depend on homologous neural circuits modulated by the same neuroendocrine mediators across vertebrates. Among neuromodulators, serotonin (5-HT) is the main inhibitor of aggression, and arginine vasotocin (AVT) underlies sexual, individual and social context differences in behavior across vertebrate taxa. We aim to demonstrate that a distinct spatio-temporal pattern of activation of the social behavior network characterizes each type of aggression by exploring its modulation by both the 5-HT and AVT systems. We analyze the neuromodulation of aggression between the intermale reproduction-related aggression displayed by the gregarious Brachyhypopomus gauderio and the non-breeding intrasexual and intersexual territorial aggression displayed by the solitary Gymnotus omarorum. Differences in the telencephalic activity of 5-HT between species were paralleled by a differential serotonergic modulation through 1A receptors that inhibited aggression in the territorial aggression of G. omarorum but not in the reproduction-related aggression of B. gauderio. AVT injection increased the motivation towards aggression in the territorial aggression of G. omarorum but not in the reproduction-related aggression of B. gauderio, whereas the electric submission and dominance observed in G. omarorum and B. gauderio, respectively, were both AVT-dependent in a distinctive way. The advantages of our model species allowed us to identify precise target areas and mechanisms of the neuromodulation of two types of aggression that may represent more general and conserved strategies of the control of social behavior among vertebrates.

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Physiology and ultrastructure of electrotonic junctions. IV. Medullary electromotor nuclei in gymnotid fish.

Cited by 231 publications

References 0 publications

Segregation of Behavior-Specific Synaptic Inputs to a Vertebrate Neuronal Oscillator

Segregation of Behavior-Specific Synaptic Inputs to a Vertebrate Neuronal Oscillator

Large-scale identification of proteins involved in the development of a sexually dimorphic behavior

Neuromodulation of the agonistic behavior in two species of weakly electric fish that display different types of aggression

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