Thoracic Ganglia

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Hiroshi Washio - One of the best experts on this subject based on the ideXlab platform.

  • glutamate receptors on the somata of dorsal unpaired median neurons in cockroach periplaneta americana Thoracic Ganglia
    Zoological Science, 2002
    Co-Authors: Hiroshi Washio
    Abstract:

    Effects of application of glutamate and glutamatergic ligands were studied to characterize the receptors for glutamate present on the soma membrane of the dorsal unpaired median (DUM) neurons in the Thoracic Ganglia of the cockroach, Periplaneta americana, using the intracellular recording technique. Application of L-glutamate did not block the GABA-response, and application of beta-guanidino-propionic acid, a competitive antagonist for GABA, failed to block the response to L-glutamate. These results indicate that most of L-glutamate action may not be mediated by a GABA-activated channel. To examine glutamate receptor types on the DUM neurons, glutamate receptor agonists were applied. The ionotropic glutamate receptor (iGluR) agonists evoked depolarizations with the following relative rank of order of potency: kainate > AMPA > quisqualate. Metabotropic glutamate receptor (mGluR) agonists also elicited membrane depolarizations or hyperpolarizations associated with an increase in membrane conductance. The mGluR agonists evoked depolarizations or hyperpolarizations with the following relative rank of order: L-CCG-1 > 1S, 3R-ACPD > L-AP4. Depolarization of the same DUM neuron was detected following exposure of kainate and L-CCG-I, suggesting the coexistence of distinct iGluR and mGluR types. A membrane permeable cAMP analog, CPT-cAMP, could not mimic the effect of mGluR agonists. The mGluR selective antagonists, MCCG and MCPG, failed to antagonize the response to mGluR agonists. The involvement of cAMP in the mGluR response was not confirmed in DUM neurons. Although the functional roles of these receptors are unknown, it might be possible then that these extrasynaptic receptors have a modulatory effect on the excitability of the DUM neurons.

  • Effects of putative neurotransmitters on dorsal unpaired median neurons of cockroach (Periplaneta americana) Thoracic Ganglia
    Journal of Insect Physiology, 1994
    Co-Authors: Hiroshi Washio
    Abstract:

    Abstract Effects of bath applications of glutamate and gamma-aminobutyric acid (GABA) were studied to characterize the receptors for putative neurotransmitters present on soma membranes of the dorsal unpaired median (DUM) neurons of the Thoracic Ganglia in the cockroach, Periplaneta americana , using the intracellular recording technique. Both l -glutamate and GABA at concentrations of 10 −4 M produced a depolarization or a hyperpolarization at resting membrane potentials accompanied by an increase in membrane conductance, and inhibited spontaneous spikes. The reversal potential (about −40 mV) was almost the same for l -glutamate and GABA. Responses to the amino acids were completely blocked by picrotoxin, and were sensitive to a low chloride saline. The responses were reversed when chloride was injected into the cell. These results provide evidence for l -glutamate and GABA inhibitory receptors on the soma membrane of the DUM neurons linked to a chloride channel. Possible functional significance of these receptors are discussed.

  • some effects of octopamine proctolin and serotonin on dorsal unpaired median neurones of cockroach periplaneta americana Thoracic Ganglia
    Journal of Insect Physiology, 1992
    Co-Authors: Hiroshi Washio, Yoshitaka Tanaka
    Abstract:

    Abstract Effects of neuromodulators, two monoamines, octopamine and serotonin, and the pentapeptide, proctolin, known to be present in the cockroach central nervous system, on the excitability of dorsal unpaired median neurones in the Thoracic Ganglia of the cockroach, Periplaneta americana, were investigated using intracellular recording technique. Octopamine had a marked excitatory effect on these neurones. Bath application of octopamine increased the frequency of spontaneous spikes in a dose-dependent manner associated with an increase in membrane input resistance. Serotonin increased the frequency and the resistance, but much less than octopamine. Proctolin also had an excitatory effect on the dorsal unpaired median somata, but the effect was somewhat equivocal. No appreciable change in the membrane input resistance occurred in the presence of proctolin. Among these neuromodulators tested, octopamine may alter the intrinsic properties of the above somata, resulting in the modulation of neural networks.

Peter Skorupski - One of the best experts on this subject based on the ideXlab platform.

  • antagonistic effects of phentolamine and octopamine on rhythmic motor output of crayfish Thoracic Ganglia
    Journal of Neurophysiology, 1999
    Co-Authors: Mark D Gill, Peter Skorupski
    Abstract:

    Spontaneous rhythmic motor output of crayfish Thoracic Ganglia consists of bursts of activity in antagonistic leg motor neurons (MNs), alternating with a rather slow cycle period (typically ≥20 s)....

  • octopamine induces steady state reflex reversal in crayfish Thoracic Ganglia
    Journal of Neurophysiology, 1996
    Co-Authors: Peter Skorupski
    Abstract:

    1. This paper investigates the effect of octopamine on spontaneous and reflex motor output of crayfish leg motor neurons. Octopamine modulated spontaneous activity, both rhythmic and tonic, and dramatically modulated the pattern of reflex motor output elicited by stimulating identified proprioceptors of the basal limb. 2. Spontaneous reciprocal motor patterns, involving alternating bursts of promotor and remotor motor neuron activity, were reversibly abolished by octopamine. The threshold concentration for this effect was approximately 1 microM. 3. At concentrations greater than approximately 10 microM octopamine inhibited spontaneous promotor nerve activity in both bursting and nonbursting preparations. In some experiments promotor inhibition was correlated with the induction of tonic remotor nerve activity. The EC50 for complete inhibition of promotor nerve activity by octopamine was 20-30 microM. 4. Reflexes mediated by two basal limb proprioceptors, the thoracocoxal muscle receptor organ (TCMRO; which signals leg promotion) and the thoracocoxal chordotonal organ (TCCO; which signals leg remotion) were analyzed in a number of promotor and remotor motor neurons. In both cases assistance reflexes (excitation of promotors by the TCCO and remotors by the TCMRO) were restricted to subgroups of the motor pool. Among remotor motor neurons, the first two units recruited during bursts of spontaneous activity were members of the assistance reflex group (group 1). A third unit, sometimes recruited during more intense spontaneous bursts, was excited by TCCO stimulation and was therefore a member of the resistance reflex group (group 2). Other resistance group remotors were also excited by the TCCO, but this input normally remained subthreshold. 5. Stimulation of the TCCO afferent nerve elicited excitatory postsynaptic potentials (EPSPs) in group 2 (resistance group) remotor motor neurons at a latency compatible with a monosynaptic connection. The same stimulation excited group 1 (assistance group) promotor motor neurons, but at a greater and more variable latency. Thus the remotor resistance reflex from the TCCO is probably monosynaptic, but the promotor assistance reflex, also elicited by TCCO stimulation, is likely to be di- or polysynaptic. Assistance group (group 1) remotor motor neurons are inhibited by mechanical stimulation of the TCCO, or electrical stimulation of its nerve. 6. Octopamine had selective effects on individual remotor units. First, assistance group remotor motor neurons were affected in two ways. One unit was inhibited, so that reflex spiking in response to TCMRO stimulation was abolished. A second unit was not inhibited, but its reflex response mode changed, so that instead of responding to TCMRO input with an assistance reflex, it responded to TCCO input with a resistance reflex. Second, among motor neurons that normally respond to TCCO input with resistance reflexes, these responses were enhanced by octopamine. 7. Promotor motor neurons were inhibited by octopamine and reflex responses were also affected selectively. Responses to TCCO input (assistance reflexes) were abolished; whereas, responses to TCMRO input (resistance reflexes) were relatively less affected. 8. Intracellular recordings revealed that the majority of remotor motor neurons depolarized in the presence of octopamine. In preparations where these could be classified on the basis of TCMRO/ TCCO inputs, all were identified as group 2 (resistance group). A minority of remotor motor neurons were hyperpolarized by octopamine. All of these were identified as group 1 (assistance group), with strong TCMRO input. 9. The majority of promotor motor neurons were depolarized by octopamine. This depolarization was nevertheless inhibitory since it reversed slightly positive to rest and was associated with a substantial fall in inp

Prasert Sobhon - One of the best experts on this subject based on the ideXlab platform.

  • distribution and changes of serotonin and dopamine levels in the central nervous system and ovary of the pacific white shrimp litopenaeus vannamei during ovarian maturation cycle
    Cell and Tissue Research, 2011
    Co-Authors: Yotsawan Tinikul, Jaruwan Poljaroen, Napamanee Kornthong, Charoonroj Chotwiwatthanakun, Panat Anuracpreeda, Tanes Poomtong, Peter J Hanna, Prasert Sobhon
    Abstract:

    We investigated changes in serotonin (5-HT) and dopamine (DA) levels and in their distribution patterns in the central nervous system (CNS) and ovary during the ovarian maturation cycle in the Pacific white shrimp, Litopenaeus vannamei. The concentrations of these two neurotransmitters were determined by using high performance liquid chromatography with electrochemical detection. The 5-HT concentration exhibited a gradual increase in the brain and Thoracic Ganglia during early ovarian stages I, II, and III, reaching a maximum at the mature ovarian stage IV, whereas DA showed its highest concentration at ovarian stage II in the brain and Thoracic Ganglia and then declined to its lowest concentration at ovarian stage IV. In the ovaries, 5-HT was lowest at ovarian stage I and gradually increased to a peak at ovarian stage IV. Conversely, the concentration of DA was highest at ovarian stages I and II and lowest at ovarian stage IV. In the brain, 5-HT immunoreactivity (−ir) from stage IV and DA-ir from stage II were distributed extensively in neurons of clusters 6, 11, and 17, in fibers, and in the anterior and posterior medial protocerebral, olfactory, antenna II, and tegumentary neuropils. In the circumesophageal, subesophageal, Thoracic, and abdominal Ganglia, both 5-HT-ir and DA-ir were detected in neuropils and surrounding neurons and fibers. 5-HT-ir and DA-ir were more intense in the Thoracic Ganglia than in other parts of the CNS. In the ovary, 5-HT-ir exhibited high intensity in late oocytes, whereas DA-ir was more intense in early oocytes. Thus, opposing changes occur in the levels of these two neurotransmitters and in their specific localizations in the CNS and ovary during ovarian maturation, indicating their important involvement in female reproduction.

  • distribution of dopamine and octopamine in the central nervous system and ovary during the ovarian maturation cycle of the giant freshwater prawn macrobrachium rosenbergii
    Tissue & Cell, 2009
    Co-Authors: Yotsawan Tinikul, Joffre A Mercier, Prasert Sobhon
    Abstract:

    Dopamine (DA), octopamine (OA) and serotonin (5-HT) are the key neurotransmitters that control gonadal development in decapod crustaceans. 5-HT stimulates, while DA and OA delay gonadal development in Macrobrachium rosenbergii. In the present study, we have further investigated the distribution patterns of DA and OA in the central nervous system (CNS) and ovary during various stages of the ovarian maturation cycle of this giant freshwater prawn. DA- and OA-immunoreactive neurons and fibers were distributed extensively in several regions of the brain, subesophageal ganglion (SEG), Thoracic Ganglia and abdominal Ganglia. In the brain, the two neurotransmitters were present in neurons of clusters 6, 7, 11, 17, and nearby neuropil regions. In the SEG, Thoracic Ganglia and abdominal Ganglia, immunoreactive neurons and fibers were found along the midline and in several neuronal clusters around each neuropil region. Staining for DA and OA was more intense in the Thoracic Ganglia than in other parts of the CNS. In the ovary, DA- and OA-immunoreactivities were present at high intensity in early oocytes. The presence of DA- and OA-immunoreactivities in neural Ganglia as well as ovary suggests that DA and OA may also be involved in the reproductive process, particularly ovarian development and differentiation of oocytes in this species.

Yoshitaka Tanaka - One of the best experts on this subject based on the ideXlab platform.

  • some effects of octopamine proctolin and serotonin on dorsal unpaired median neurones of cockroach periplaneta americana Thoracic Ganglia
    Journal of Insect Physiology, 1992
    Co-Authors: Hiroshi Washio, Yoshitaka Tanaka
    Abstract:

    Abstract Effects of neuromodulators, two monoamines, octopamine and serotonin, and the pentapeptide, proctolin, known to be present in the cockroach central nervous system, on the excitability of dorsal unpaired median neurones in the Thoracic Ganglia of the cockroach, Periplaneta americana, were investigated using intracellular recording technique. Octopamine had a marked excitatory effect on these neurones. Bath application of octopamine increased the frequency of spontaneous spikes in a dose-dependent manner associated with an increase in membrane input resistance. Serotonin increased the frequency and the resistance, but much less than octopamine. Proctolin also had an excitatory effect on the dorsal unpaired median somata, but the effect was somewhat equivocal. No appreciable change in the membrane input resistance occurred in the presence of proctolin. Among these neuromodulators tested, octopamine may alter the intrinsic properties of the above somata, resulting in the modulation of neural networks.

Donald H. Gilden - One of the best experts on this subject based on the ideXlab platform.

  • Expression of protein encoded by varicella-zoster virus open reading frame 63 in latently infected human ganglionic neurons.
    Proceedings of the National Academy of Sciences of the United States of America, 1996
    Co-Authors: Ravy Mahalingam, Mary Wellish, Randall J. Cohrs, Serge Debrus, Jacques Piette, Bernard Rentier, Donald H. Gilden
    Abstract:

    Abstract The ganglionic cell type in which varicella-zoster virus (VZV) is latent in humans was analyzed by using antibodies raised against in vitro-expressed VZV open reading frame 63 protein. VZV open reading frame 63 protein was detected exclusively in the cytoplasm of neurons of latently infected human trigeminal and Thoracic Ganglia. This is, to our knowledge, the first identification of a herpesvirus protein expressed during latency in the human nervous system.

  • restricted transcription of varicella zoster virus in latently infected human trigeminal and Thoracic Ganglia
    The Journal of Infectious Diseases, 1992
    Co-Authors: Randall J. Cohrs, Mary Wellish, Ravi Mahalingam, William Wolf, Aud N Dueland, Donald H. Gilden
    Abstract:

    Normal human trigeminal and Thoracic Ganglia latently infected with varicella-zoster virus (VZV) were identified by polymerase chain reaction (PCR). Total RNA was extracted from these Ganglia and treated with DNase until ganglionic RNA was free of VZV DNA as determined by PCR. Radiolabeled cDNA synthesized by priming with random oligonucleotides was hybridized to Southern blots containing recombinant clones that spanned greater than 95% of the VZV genome. The single region of the VZV genome detected was the 12.5-kb SalI C fragment located in the unique long segment of the viral genome. Two additional regions of the VZV genome, EcoRI G and SalI B, were detected in RNA from adult dorsal root Ganglia and infant nervous system tissue.