Synaptic neuropil in nerves of the crustacean stomatogastric nervous system: An immunocytochemical and electron microscopical study

Skiebe, Petra; Ganeshina, Olga

doi:10.1002/(sici)1096-9861(20000508)420:3<373::aid-cne8>3.0.co;2-t

Cited by 32 publications

(44 citation statements)

References 42 publications

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“…They are distinct from larger neurohemal structures that lie at the nerve-sheath interface or within the sheath. In other species this region of punctate staining within the nerve has also been shown previously to have synaptic contacts (Skiebe and Ganeshina, 2000;Skiebe and Wollenschlager, 2002) that are labeled with synaptotagmin.…”

Section: Resultssupporting

confidence: 80%

“…Axons traveling through areas of local neuromodulatory release could be influenced by the chemical environment, thus gating, inhibiting, or enhancing the traffic through that site. In the case of the stomatogastric nervous system, clearly there is a local neuropil ideally positioned at the stn-son junction to facilitate bilateral coordination (Skiebe and Ganeshina, 2000). It is equally possible that axonal receptors in other circuits gate information passage and that axons may often be conditional rather than reliable conduits for carrying information.…”

Section: Will Axonal Receptors Be Common?mentioning

confidence: 99%

“…Therefore, this site is special, because it is the first anatomical location at which bilaterally arising neuronal pathways can interact. Interestingly, numerous immunocytochemical studies have shown areas of what appear to be neuropilar-like varicosities and branches in this location (Marder et al, , 1987Kilman et al, 1999;Skiebe, 1999;Skiebe et al, 1999), and this is also a site at which synapses are seen (Kilman, 1998;Skiebe and Ganeshina, 2000;Skiebe and Wollenschlager, 2002). We now find that the axons of the MCN5 neurons are sensitive to octopamine at this site and that the ef-fects of octopamine on the pyloric rhythm of the crab depend both on its actions on the STG itself and on the axons of the MCN5 neurons.…”

Section: Introductionmentioning

confidence: 99%

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Octopamine Modulates the Axons of Modulatory Projection Neurons

et al. 2004

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Octopamine increases the cycle frequency of the pyloric rhythm in the crab Cancer borealis by acting at multiple sites within the stomatogastric nervous system. The junction between the stomatogastric nerve (stn) and the superior esophageal nerve (son) shows synaptic structures. When applied only to the stn-son junction, octopamine induced action potentials in the axons of the modulatory commissural neuron 5 (MCN5) that project from the commissural ganglia to the stomatogastric ganglion (STG). The activation of the MCN5 neurons was correlated with an increase in the pyloric rhythm frequency. Additionally, octopamine had direct effects on the STG, including the activation of the pyloric dilator and pyloric neurons, an increase in the pyloric frequency, and a change in the phase relationships of the pyloric neurons. Thus, the same modulator can influence the pyloric rhythm by acting at multiple sites, including the axons of identified modulatory neurons that project to the STG. These data demonstrate that axonal propagation may be influenced locally by neuromodulators acting on axonal receptors, therefore altering the conduction of information from different command and integrating centers.

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Section: Resultssupporting

confidence: 80%

Section: Will Axonal Receptors Be Common?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Octopamine Modulates the Axons of Modulatory Projection Neurons

et al. 2004

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“…Using this antibody, we mapped the distribution of putative synaptic neuropil in the STNS of P. producta and found it to be essentially identical to that reported previously for other brachyuran species (Skiebe and Ganeshina, 2000;Skiebe and Wollenschlager, 2002). Specifically, synapsin labeling was routinely seen in the CoGs and the STG, but not in the OG.…”

Section: Location Of Putative Synaptic Neuropil In the Stomatogastricsupporting

confidence: 71%

“…Previous studies have shown that an antibody to the synaptic vesicleassociated protein synapsin labels regions of synaptic neuropil in the crustacean STNS (Skiebe and Ganeshina, 2000;Skiebe and Wollenschlager, 2002). Using this antibody, we mapped the distribution of putative synaptic neuropil in the STNS of P. producta and found it to be essentially identical to that reported previously for other brachyuran species (Skiebe and Ganeshina, 2000;Skiebe and Wollenschlager, 2002).…”

Section: Location Of Putative Synaptic Neuropil In the Stomatogastricsupporting

confidence: 68%

The pyloric neural circuit of the herbivorous crabPugettia productashows limited sensitivity to several neuromodulators that elicit robust effects in more opportunistically feeding decapods

Dickinson

Stemmler

Christie

2008

Journal of Experimental Biology

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SUMMARY Modulation of neural circuits in the crustacean stomatogastric nervous system (STNS) allows flexibility in the movements of the foregut musculature. The extensive repertoire of such resulting motor patterns in dietary generalists is hypothesized to permit these animals to process varied foods. The foregut and STNS of Pugettia producta are similar to those of other decapods, but its diet is more uniform, consisting primarily of kelp. We investigated the distribution of highly conserved neuromodulators in the stomatogastric ganglion (STG) and neuroendocrine organs of Pugettia,and documented their effects on its pyloric rhythm. Using immunohistochemistry, we found that the distributions of Cancer borealis tachykinin-related peptide I (CabTRP I), crustacean cardioactive peptide (CCAP), proctolin, red pigment concentrating hormone (RPCH) and tyrosine hydroxylase (dopamine) were similar to those of other decapods. For all peptides except proctolin, the isoforms responsible for the immunoreactivity were confirmed by mass spectrometry to be the authentic peptides. Only two modulators had physiological effects on the pyloric circuit similar to those seen in other species. In non-rhythmic preparations,proctolin and the muscarinic acetylcholine agonist oxotremorine consistently initiated a full pyloric rhythm. Dopamine usually activated a pyloric rhythm,but this pattern was highly variable. In only about 25% of preparations, RPCH activated a pyloric rhythm similar to that seen in other species. CCAP and CabTRP I had no effect on the pyloric rhythm. Thus, whereas Pugettiapossesses all the neuromodulators investigated, its pyloric rhythm, when compared with other decapods, appears less sensitive to many of them, perhaps because of its limited diet.

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