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Toshiki Nagayama - One of the best experts on this subject based on the ideXlab platform.
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Excitatory connections of nonspiking interneurones in the terminal Abdominal Ganglion of the crayfish
Journal of comparative physiology. A Neuroethology sensory neural and behavioral physiology, 2015Co-Authors: H. Namba, Toshiki NagayamaAbstract:The output effects of the nonspiking interneurones in the crayfish terminal Abdominal Ganglion upon the uropod motor neurones were characterized using simultaneous intracellular recordings. Inhibitory interactions from nonspiking interneurones to the uropod motor neurones were one-way and chemically mediated. The depolarization of the motor neurones with current injection increased the amplitude of the nonspiking interneurone-mediated hyperpolarization, while hyperpolarization of the motor neurone decreased it. By contrast, excitatory interactions from the nonspiking interneurones to the motor neurones were not mediated via chemical synaptic transmissions. These excitatory connections with the slow motor neurones were one-way while connections with fast motor neurones were bidirectional. Nonspiking interneurone-mediated membrane depolarization of the motor neurones was not affected by the passage of hyperpolarizing current. Each motor neurone spike elicited a time-locked EPSP in the nonspiking interneurones with very short delay (0.2 ms) that suggested electrical coupling between nonspiking interneurones and motor neurones. Nonspiking interneurones directly control the organization of slow motor neurone activity, while they appear to regulate the background activity of the fast motor neurones. A single nonspiking interneurone is possible to inhibit some inter and/or motor neurones via direct chemical synapses and simultaneously excite other neurones via electrical synapses.
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GABAergic and glutamatergic inhibition of nonspiking local interneurons in the terminal Abdominal Ganglion of the crayfish.
Journal of experimental zoology. Part A Comparative experimental biology, 2005Co-Authors: Toshiki NagayamaAbstract:Nonspiking local interneurons in the terminal Abdominal Ganglion of the crayfish Procambarus clarkii receive inhibitory inputs from mainly glutamatergic spiking local interneurons and GABAergic nonspiking interneurons. In this study, the inhibitory responses of nonspiking interneurons to local application of glutamate and GABA into the neuropil were compared. Glutamate and GABA injection mediated the hyperpolarization of the nonspiking interneurons with an increase in membrane conductance. The glutamate-mediated membrane hyperpolarization was reversed by injection of 1 or 2 nA hyperpolarizing current. By contrast, more than 3 nA hyperpolarizing current was frequently necessary to reverse the GABA-mediated hyperpolarization. Bath application of a chloride channel blocker, 50 microM picrotoxin (PTX), reduced the glutamate-mediated hyperpolarization, but had no effect on the GABA-mediated hyperpolarization. The GABA-mediated hyperpolarization was not consistently affected by bath application of low chloride solution. These results suggest that the glutamate-mediated inhibition was related to the gating of a Cl(-) conductance, while the GABA-mediated inhibition was not. Electrical stimulation of sensory afferents innervating the exopodite elicited ipsps in uropod opener motor neurons. These sensory-evoked ipsps were also PTX-insensitive, suggesting GABAergic nonspiking interneurons could be the predominant premotor elements in organizing the uropod motor control system.
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Distribution of glutamatergic immunoreactive neurons in the terminal Abdominal Ganglion of the crayfish
The Journal of comparative neurology, 2004Co-Authors: Toshiki Nagayama, Hitoshi Aonuma, Ken-ichi Kimura, Makoto Araki, Philip L. NewlandAbstract:Using an antiserum directed against glutamate, we have analyzed the distribution of glutamate-like immunoreactive neurons in the terminal Abdominal Ganglion of the crayfish Procambarus clarkii. Approximately 160 central neurons (157 8; mean SEM, n 8) showed positive glutamate-like immunoreactivity, which represents approximately 25% of the total number of neurons in the terminal Ganglion. Using a combination of intracellular staining with the marker Lucifer yellow and immunocytochemical staining has shown that most excitatory motor neurons are glutamatergic and that glutamate acts as an excitatory transmitter at peripheral neuromuscular junctions. Seven of 10 identified spiking local interneurons and only 2 of 19 identified ascending interneurons, showed positive immunoreactivity. Our observation that inhibitory spiking interneurons were immunopositive, whereas excitatory ascending interneurons were immunonegative, indicates that glutamate is likely to act as an inhibitory neurotransmitter within the central nervous system. Local pressure injection of L-glutamate into the neuropil of the Ganglion caused a hyperpolarization of the membrane potentials of many interneurons. -Aminobutyric acid (GABA)ergic posterolateral nonspiking interneurons and the bilateral nonspiking interneuron LDS showed no glutamate-like immunoreactivity, whereas nonGABAergic anterolateral III nonspiking interneurons showed glutamate-like immunoreactivity. Thus, not only GABA but also glutamate are used in parallel as inhibitory neurotransmitters at central synapses. J. Comp. Neurol. 474:123–135, 2004. © 2004 Wiley-Liss, Inc.
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Serotonergic modulation of nonspiking local interneurones in the terminal Abdominal Ganglion of the crayfish.
The Journal of Experimental Biology, 2002Co-Authors: Toshiki NagayamaAbstract:SUMMARY The modulatory effect of serotonin on local circuit neurones forming the uropod motor control system of the crayfish Procambarus clarkii Girard was analysed electrophysiologically. Bath application of 10 μmol l-1 serotonin caused a decrease in the tonic spike activity of the exopodite reductor motor neurone. The inhibitory effect of serotonin on the motor neurone was dose-dependent and its spike discharge was completely suppressed for long periods by 1 mmol l-1 serotonin perfusion. Nonspiking local interneurones in the terminal Abdominal Ganglion showed either a membrane depolarization (N=6) or hyperpolarization (N=9) of 10-30 mV in amplitude when 100 μmol l-1 serotonin was perfused for 3-5 min. By contrast, spiking local interneurones and intersegmental ascending interneurones showed no observable excitatory responses to the perfusion of serotonin but instead some showed a small membrane hyperpolarization of 2-5 mV. These results indicate that the nonspiking interneurones could contribute substantially to the level of tonic excitation of the uropod motor neurones. Sensory stimulation elicited depolarizing or hyperpolarizing potentials in the nonspiking interneurones and excitatory postsynaptic potentials (EPSPs) and spikes in the spiking interneurones. The sensory responses of spiking interneurones increased during bath application of serotonin and were reduced after 20-30 min of washing with normal saline. In the nonspiking interneurones, the amplitude of both depolarizing and hyperpolarizing potentials increased without any direct correlation with the serotonin-mediated potential change. This effect of serotonin was long-lasting and continued to enhance the responses of the nonspiking interneurones after washing. This postserotonin enhancement persisted for over 1 h.
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Synaptic Organization of Local Circuit Neurons in the Terminal Abdominal Ganglion of the Crayfish
The Crustacean Nervous System, 2002Co-Authors: Toshiki NagayamaAbstract:The synaptic organization of the local circuit generation uropod movements of the crayfish has been analyzed by using electrophysiological, pharmacological and immunocytochemical techniques. Sensory afferents innervating hairs on the tailfan contain the neurotransmitter acetylcholine and make direct excitatory synaptic connections with intersegmental ascending interneurones, spiking local interneurones and nonspiking local interneurones in the terminal (sixth) Abdominal Ganglion. Ascending interneurones, in turn, make excitatory connections with nonspiking interneurones while spiking local interneurones make direct inhibitory connection with nonspiking interneurones. Most nonspiking interneurones contain the inhibitory neurotransmitter, GABA, and play a prominent premotor role in organizing the motor patterns of the uropods.
Angela B. Lange - One of the best experts on this subject based on the ideXlab platform.
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CONTROL OF THE MOTOR PATTERN GENERATOR IN THE VIITH Abdominal Ganglion OF LOCUSTA : DESCENDING NEURAL INHIBITION AND COORDINATION WITH THE OVIPOSITION HOLE DIGGING CENTRAL PATTERN GENERATOR
Journal of Insect Physiology, 1996Co-Authors: Giovanni Facciponte, Angela B. LangeAbstract:Abstract The control of a motor pattern generator in the VIIth Abdominal Ganglion of Locusta was examined. Sucrose gap block of ventral nerve cord neural activity in non-egg-laying locusts, anterior to the VIIth Abdominal Ganglion, initiated the rhythmic neural activity in the oviducal nerves which is produced by this motor pattern generator. Removal of the sucrose gap block resulted in the cessation of the pattern. Extracellular stimulation of the nerve cord caused the inhibition of the rhythmic neural activity in preparations in which the pattern was initiated by transection of the ventral nerve cord. Taken together, these results confirm that the main control of the central pattern generator in the VIIth Abdominal Ganglion is by descending neural inhibition. Using serial transections of the ventral nerve cord, the source of the inhibition was localized to the brain, suboesophageal Ganglion and thoracic ganglia. In addition to being controlled by descending neural inhibition, the motor pattern generator in the VIIth Abdominal Ganglion was also found to be coordinated with the oviposition digging central pattern generator in the VIIIth Abdominal Ganglion. The data suggest that communication with the digging central pattern generator may be important in view of the fact that the outputs of these distinct pattern generators are highly coordinated.
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Characterization of a novel central pattern generator located in the VIIth Abdominal Ganglion of Locusta
Journal of Insect Physiology, 1992Co-Authors: Giovanni Facciponte, Angela B. LangeAbstract:Abstract The neural activity recorded at the oviducal nerves of semi-intact non-egg-laying locusts and disturbed egg-laying locusts has been examined. A rhythmic motor pattern comprising predominantly three discernible sizes of action potentials could be recorded from disturbed egg-layers but not from non-egg-layers. The larger and smaller action potentials burst in a coordinated way which were mutually exclusive to the medium-sized action potential. The medium-sized action potential was found to produce typical electromyographic responses at the innervated regions of the oviduct while the larger and smaller action potentials produced similar responses at the external ventral protractor of the VIIth Abdominal segment. The minimal neural substrate required to produce this rhythmic motor pattern resides entirely in the VIIth Abdominal Ganglion as shown by transections. The data presented suggests that a central pattern generator controlling the reciprocal contractions of the innervated regions of the oviduct and the external ventral protractors of the VIIth Abdominal segment is located in the VIIth Abdominal Ganglion and is controlled by descending neural inhibition. Possible functions of this central pattern generator are discussed.
Tsukasa Gotow - One of the best experts on this subject based on the ideXlab platform.
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physiology of simple photoreceptors in the Abdominal Ganglion of onchidium
BVAI'07 Proceedings of the 2nd international conference on Advances in brain vision and artificial intelligence, 2007Co-Authors: Takako Nishi, Kyoko Shimotsu, Tsukasa GotowAbstract:Simple photoreceptors without microvilli or cilia, the photorescponsive neurons, designated as A-P-1, Es-1, Ip-2, and Ip-1, exist in the Abdominal Ganglion of sea slug Onchidium. Of these, A-P-1 and Es-1 respond to light with a depolarizing receptor potential, caused by the closing of light-dependent, cGMP-gated K+ channels, whereas Ip-2 and Ip-1 are hyperpolarized by light, owing to the opening of the same K+ channels. Studies show the first demonstration of a new type of cGMP cascade, in which Ip-2 and Ip-1 cells are hyperpolarized when light activates GC through a Go-type G-protein. This new cascade thus contrasts with the well-known phototransduction cGMP cascade mediated by a Gt-type G-protein, seen in rods and cones as well as A-P-1 and Es-1 cells. Studies also suggest that the Onchidium simple photoreceptors and vertebrate simple photoreceptors, called ipRGCs, might be different from the conventional eye photoreceptors, which function as the pattern vision system and that they may be involved in a new sensory modality, the non-visual photoreceptive system, which functions as encoding of ambient light intensities, instead of spatial and temporal resolution. Finally, it is suggested that the Onchidium simple photoreceptors operate in the general regulation by light and dark of synaptic transmission of sensory inputs and subsequent behavioral responses.
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BVAI - Physiology of simple photoreceptors in the Abdominal Ganglion of Onchidium
Lecture Notes in Computer Science, 2007Co-Authors: Takako Nishi, Kyoko Shimotsu, Tsukasa GotowAbstract:Simple photoreceptors without microvilli or cilia, the photorescponsive neurons, designated as A-P-1, Es-1, Ip-2, and Ip-1, exist in the Abdominal Ganglion of sea slug Onchidium. Of these, A-P-1 and Es-1 respond to light with a depolarizing receptor potential, caused by the closing of light-dependent, cGMP-gated K+ channels, whereas Ip-2 and Ip-1 are hyperpolarized by light, owing to the opening of the same K+ channels. Studies show the first demonstration of a new type of cGMP cascade, in which Ip-2 and Ip-1 cells are hyperpolarized when light activates GC through a Go-type G-protein. This new cascade thus contrasts with the well-known phototransduction cGMP cascade mediated by a Gt-type G-protein, seen in rods and cones as well as A-P-1 and Es-1 cells. Studies also suggest that the Onchidium simple photoreceptors and vertebrate simple photoreceptors, called ipRGCs, might be different from the conventional eye photoreceptors, which function as the pattern vision system and that they may be involved in a new sensory modality, the non-visual photoreceptive system, which functions as encoding of ambient light intensities, instead of spatial and temporal resolution. Finally, it is suggested that the Onchidium simple photoreceptors operate in the general regulation by light and dark of synaptic transmission of sensory inputs and subsequent behavioral responses.
Giovanni Facciponte - One of the best experts on this subject based on the ideXlab platform.
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CONTROL OF THE MOTOR PATTERN GENERATOR IN THE VIITH Abdominal Ganglion OF LOCUSTA : DESCENDING NEURAL INHIBITION AND COORDINATION WITH THE OVIPOSITION HOLE DIGGING CENTRAL PATTERN GENERATOR
Journal of Insect Physiology, 1996Co-Authors: Giovanni Facciponte, Angela B. LangeAbstract:Abstract The control of a motor pattern generator in the VIIth Abdominal Ganglion of Locusta was examined. Sucrose gap block of ventral nerve cord neural activity in non-egg-laying locusts, anterior to the VIIth Abdominal Ganglion, initiated the rhythmic neural activity in the oviducal nerves which is produced by this motor pattern generator. Removal of the sucrose gap block resulted in the cessation of the pattern. Extracellular stimulation of the nerve cord caused the inhibition of the rhythmic neural activity in preparations in which the pattern was initiated by transection of the ventral nerve cord. Taken together, these results confirm that the main control of the central pattern generator in the VIIth Abdominal Ganglion is by descending neural inhibition. Using serial transections of the ventral nerve cord, the source of the inhibition was localized to the brain, suboesophageal Ganglion and thoracic ganglia. In addition to being controlled by descending neural inhibition, the motor pattern generator in the VIIth Abdominal Ganglion was also found to be coordinated with the oviposition digging central pattern generator in the VIIIth Abdominal Ganglion. The data suggest that communication with the digging central pattern generator may be important in view of the fact that the outputs of these distinct pattern generators are highly coordinated.
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Characterization of a novel central pattern generator located in the VIIth Abdominal Ganglion of Locusta
Journal of Insect Physiology, 1992Co-Authors: Giovanni Facciponte, Angela B. LangeAbstract:Abstract The neural activity recorded at the oviducal nerves of semi-intact non-egg-laying locusts and disturbed egg-laying locusts has been examined. A rhythmic motor pattern comprising predominantly three discernible sizes of action potentials could be recorded from disturbed egg-layers but not from non-egg-layers. The larger and smaller action potentials burst in a coordinated way which were mutually exclusive to the medium-sized action potential. The medium-sized action potential was found to produce typical electromyographic responses at the innervated regions of the oviduct while the larger and smaller action potentials produced similar responses at the external ventral protractor of the VIIth Abdominal segment. The minimal neural substrate required to produce this rhythmic motor pattern resides entirely in the VIIth Abdominal Ganglion as shown by transections. The data presented suggests that a central pattern generator controlling the reciprocal contractions of the innervated regions of the oviduct and the external ventral protractors of the VIIth Abdominal segment is located in the VIIth Abdominal Ganglion and is controlled by descending neural inhibition. Possible functions of this central pattern generator are discussed.
Philip L. Newland - One of the best experts on this subject based on the ideXlab platform.
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Distribution of glutamatergic immunoreactive neurons in the terminal Abdominal Ganglion of the crayfish
The Journal of comparative neurology, 2004Co-Authors: Toshiki Nagayama, Hitoshi Aonuma, Ken-ichi Kimura, Makoto Araki, Philip L. NewlandAbstract:Using an antiserum directed against glutamate, we have analyzed the distribution of glutamate-like immunoreactive neurons in the terminal Abdominal Ganglion of the crayfish Procambarus clarkii. Approximately 160 central neurons (157 8; mean SEM, n 8) showed positive glutamate-like immunoreactivity, which represents approximately 25% of the total number of neurons in the terminal Ganglion. Using a combination of intracellular staining with the marker Lucifer yellow and immunocytochemical staining has shown that most excitatory motor neurons are glutamatergic and that glutamate acts as an excitatory transmitter at peripheral neuromuscular junctions. Seven of 10 identified spiking local interneurons and only 2 of 19 identified ascending interneurons, showed positive immunoreactivity. Our observation that inhibitory spiking interneurons were immunopositive, whereas excitatory ascending interneurons were immunonegative, indicates that glutamate is likely to act as an inhibitory neurotransmitter within the central nervous system. Local pressure injection of L-glutamate into the neuropil of the Ganglion caused a hyperpolarization of the membrane potentials of many interneurons. -Aminobutyric acid (GABA)ergic posterolateral nonspiking interneurons and the bilateral nonspiking interneuron LDS showed no glutamate-like immunoreactivity, whereas nonGABAergic anterolateral III nonspiking interneurons showed glutamate-like immunoreactivity. Thus, not only GABA but also glutamate are used in parallel as inhibitory neurotransmitters at central synapses. J. Comp. Neurol. 474:123–135, 2004. © 2004 Wiley-Liss, Inc.
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NADPH-diaphorase histochemistry in the terminal Abdominal Ganglion of the crayfish.
Cell and tissue research, 2001Co-Authors: Hansjürgen Schuppe, Hitoshi Aonuma, Philip L. NewlandAbstract:Nitric oxide (NO) has an important modulatory role on the processing of sensory signals in vertebrates and invertebrates. In this investigation we studied the potential sources of NO in the terminal Abdominal Ganglion of the crayfish, Pacifastacus leniusculus, using NADPH-diaphorase (NADPHd) histochemistry, with NADPHd acting as a marker for NO synthase (NOS). In the terminal Ganglion a mean of 27 strongly labelled NADPHd-positive cell bodies were found, and of these 8% occurred in three regions located in antero-lateral, central and posterior parts of the Ganglion. Ventral and antero-ventral commissures as well as specific dorsal and ventral areas of the dendritic neuropil showed positive staining. Intense labelling was seen in the ventro-medial tract, and in the connective between the terminal Ganglion and the 5th Abdominal Ganglion. In addition, some motor neurones and neurones with branches in the sensory commissures were NADPHd positive. Our finding that NADPHd-positive cells occur in consistent patterns in the terminal Abdominal Ganglion implies that NO may have a role in mechanosensory processing in the crayfish.
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Distribution of NADPH-diaphorase-positive ascending interneurones in the crayfish terminal Abdominal Ganglion
Cell and tissue research, 2001Co-Authors: Hansjürgen Schuppe, Hitoshi Aonuma, Philip L. NewlandAbstract:Previous neuropharmacological studies have described the presence of a nitric oxide-cGMP signalling pathway in the crayfish Abdominal nervous system. In this study we have analysed the distribution of putative nitric oxide synthase (NOS)-containing ascending interneurones in the crayfish terminal Abdominal Ganglion using NADPH-diaphorase (NADPHd) histochemistry. Ascending intersegmental interneurones were stained intracellularly using the fluorescent dye Lucifer yellow and the ganglia containing the stained interneurones subsequently processed for NADPHd activity. Fluorescence persisted throughout histochemical processing. These double-labelling experiments showed that 12 of 18 identified ascending interneurones were NADPHd positive. Thus many ascending interneurones that process mechanosensory signals in the terminal Ganglion may contain NOS, and are themselves likely sources of NO which is known to modulate their synaptic inputs. Three clear relationships emerged from our analysis between the effects of NO on the synaptic inputs of interneurones, their output properties and their staining for NADPH-diaphorase. First were class 1 interneurones with no local outputs in the terminal Ganglion, the NE type interneurones, which had sensory inputs that were enhanced by NO and were NADPHd positive. Second were class 1 interneurones with local and intersegmental output effects that had sensory inputs that were also enhanced by NO but were NADPHd negative. Third were class 2 interneurones with local and intersegmental outputs that had synaptic inputs that were depressed by the action of NO but were NADPHd positive. These results suggest that NO could selectively enhance specific synaptic connections and sensory processing pathways in local circuits.
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presynaptic inhibition of exteroceptive afferents by proprioceptive afferents in the terminal Abdominal Ganglion of the crayfish
Journal of Neurophysiology, 1996Co-Authors: Philip L. Newland, Hitoshi Aonuma, Motoaki Sato, Toshiki NagayamaAbstract:1. Exteroceptive hairs that are sensitive to water displacement and touch are distributed over the surface of the tailfan of crayfish. We show that the sensory neurons innervating these hairs receive a primary afferent depolarization (PAD) from sensory neurons innervating a proprioceptor that monitors movements of the endopodite and protopodite of the tailfan. This PAD occurs only during high-velocity movements of the exopodite, which are similar to those that occur during swimming. The effects that the proprioceptor mediate are widespread, so that afferents in four sensory nerve roots of the terminal Abdominal Ganglion, innervating hairs on the protopodite, exopodite, endopodite, and telson, receive a PAD. The PAD is unlikely to be mediated through monosynaptic pathways because there is no anatomic overlap between the central projections of chordotonal afferents and many of the exteroceptive afferents. The depolarization is associated with a conductance increase and can be increased by the injection of hyperpolarizing current or reversed (approximately 10 mV above resting potential) by injection of depolarizing current. The properties of the presynaptic input are, therefore, consistent with being mediated through chemical synapses. This is supported by the observation in the electron microscope that the exteroceptive afferents receive chemical input synapses. The depolarization is mimicked by gamma-aminobutyric acid and reduced by bath application of picrotoxin or bicuculline, suggesting that it is a depolarizing inhibitory postsynaptic potential. The PAD reduces the amplitude of exteroceptive afferent spikes, an action that is thus likely to reduce transmitter release and the efficacy of synaptic transmission.
