Presynaptic control of modulatory fibers by their neural network targets

Nusbaum, Michael P.; Weimann, JM; Golowasch, Jorge; Marder, Eve

doi:10.1523/jneurosci.12-07-02706.1992

Cited by 77 publications

(65 citation statements)

References 51 publications

(34 reference statements)

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“…As in other decapod species, these neurons, together with the terminals of several of the modulatory neurons that project into the STG, form the networks that generate the pyloric and gastric mill rhythms of the crab (Weimann et al, 1991;Nusbaum et al, 1992;Coleman and Nusbaum, 1994;Weimann and Marder, 1994;Coleman et al, 1995). When inputs to the STG from the paired CG are left attached, robust pyloric rhythms ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Modulation of Oscillator Interactions in the Crab Stomatogastric Ganglion by Crustacean Cardioactive Peptide

et al. 1997

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The modulation of the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis, by crustacean cardioactive peptide (CCAP) is described. CCAP activated pyloric rhythms in most silent preparations, and altered the phase relationships of pyloric motor neuron firing in all preparations. In CCAP, the pyloric rhythms were characterized by long lateral pyloric (LP) neuron bursts of action potentials. The threshold for CCAP action was ϳ10 Ϫ10 M, with increasing effects at higher CCAP concentrations. The changes in motor pattern evoked by CCAP produced significant changes in LP-innervated muscle movement. These movements were additionally potentiated by CCAP applications to isolated nerve-muscle preparations. Thus, enhanced motor neuron firing and increase of the gain of the neuromuscular junctions are likely to operate coordinately in response to hormonally released CCAP. High CCAP concentrations sometimes resulted in modification of the normal 1:1 alternation between the pyloric dilator (PD) and LP neurons to patterns of 2:1, 3:1, or 4:1 alternation. CCAP seems to activate slow intrinsic oscillations in the LP neuron, as well as enhance faster oscillations in the pacemaker group of PD/ anterior burster (AB) neurons. Simulations of fast and slow oscillators with reciprocal inhibitory coupling suggest mechanisms that could account for the mode switch from 1:1 alternation to multiple PD bursts alternating with one LP neuron burst.

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Section: Resultsmentioning

confidence: 99%

Modulation of Oscillator Interactions in the Crab Stomatogastric Ganglion by Crustacean Cardioactive Peptide

et al. 1997

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“…The proctolin degradation reported in the present study may well contribute to the relatively short-lasting excitatory effects of two proctolin-containing neurons, MPN and MCNl, on the pyloric motor pattern in the crab STG (Nusbaum and Marder, 1989a,b;Nusbaum et al, 1992;Christie et al, 1993;Coleman and Nusbaum, 1994). Whereas some modulatory neurons have effects that long outlast their period of impulse activity (HarrisWarrick et al, 1992b), the effects of both MPN and MCNl subside within seconds after their activity is terminated (Nusbaum and Marder, 1989a,b;Nusbaum et al, 1992).…”

Section: Discussionmentioning

confidence: 68%

“…Whereas some modulatory neurons have effects that long outlast their period of impulse activity (HarrisWarrick et al, 1992b), the effects of both MPN and MCNl subside within seconds after their activity is terminated (Nusbaum and Marder, 1989a,b;Nusbaum et al, 1992). Because the effects of the proctolin neurons on the pyloric rhythm are equivalent to bath application of 10m7 M to 1O-6 M proctolin and threshold for proctolin actions on this system is approximately 1O-9 M (Marder et al, 1986;Nusbaum and Marder, 1989b), the local concentration of neurally released proctolin probably decreases by 2-3 orders of magnitude within several seconds or less.…”

Section: Discussionmentioning

confidence: 99%

Neuropeptide degradation produces functional inactivation in the crustacean nervous system

et al. 1994

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The pentapeptide proctolin (Proct.; Arg-Tyr-Leu-Pro-Thr) is a modulatory transmitter found throughout the crustacean nervous system. No information is available in this system, however, as to how the actions of this peptide are terminated. To study this issue in the crab Cancer borealis, we incubated exogenous proctolin (10(-5) M) with either the thoracic ganglion (TG) or with conditioned saline (CS) that had been preincubated with the TG. We removed aliquots at standard time points for analysis by reverse-phase high-performance liquid chromatography (HPLC). We found that over time the proctolin peak became progressively smaller, while three novel peaks appeared and increased in size. Comigration experiments using HPLC indicated that the major novel peak was Proct. (Tyr-Leu-Pro-Thr), while one of the two minor peaks was Proct. (Leu-Pro-Thr). The other minor peak appeared to be Proct. (Arg-Tyr), based on similar HPLC retention time to synthetic Proct. The reduction in the proctolin peak and the increase in the Proct. peak was prevented by co-incubation of proctolin with any one of several aminopeptidase inhibitors (10(-4) M). Proct. and Proct. appeared to result from a diaminopeptidase-mediated cleavage of proctolin. We tested whether N-terminal cleavage functionally inactivated proctolin by coapplying proctolin (10(-8) M) and individual aminopeptidase inhibitors (10(-5) M) to the isolated stomatogastric ganglion (STG). We found that these inhibitors significantly enhanced the proctolin excitation of the pyloric rhythm. Furthermore, application of synthetic Proct. to the STG had no effect unless high concentrations (> 10(-6) M) were used, and neither Proct. nor Proct. (10(-4) M) influenced the pyloric rhythm. Our results indicate that proctolin is enzymatically degraded and thereby biologically inactivated in the crab nervous system, primarily by extracellularly located aminopeptidase activity.

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“…containing the modulatory somata (Blitz and Nusbaum 2012;Nusbaum et al 1992). Previous work has demonstrated a rich diversity of roles for these projection neurons in driving and shaping gastric behavior, as well as influencing interactions between the pyloric and gastric rhythms White and Nusbaum 2011;Wood et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Consequences of acute and long-term removal of neuromodulatory input on the episodic gastric rhythm of the crabCancer borealis

Hamood

Marder

2015

Journal of Neurophysiology

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Hamood AW, Marder E. Consequences of acute and long-term removal of neuromodulatory input on the episodic gastric rhythm of the crab Cancer borealis. J Neurophysiol 114: 1677-1692. First published July 8, 2015 doi:10.1152/jn.00536.2015.-For decades, the episodic gastric rhythm of the crustacean stomatogastric nervous system (STNS) has served as an important model system for understanding the generation of rhythmic motor behaviors. Here we quantitatively describe many features of the gastric rhythm of the crab Cancer borealis under several conditions. First, we analyzed spontaneous gastric rhythms produced by freshly dissected preparations of the STNS, including the cycle frequency and phase relationships among gastric units. We find that phase is relatively conserved across frequency, similar to the pyloric rhythm. We also describe relationships between these two rhythms, including a significant gastric/ pyloric frequency correlation. We then performed continuous, dayslong extracellular recordings of gastric activity from preparations of the STNS in which neuromodulatory inputs to the stomatogastric ganglion were left intact and also from preparations in which these modulatory inputs were cut (decentralization). This allowed us to provide quantitative descriptions of variability and phase conservation within preparations across time. For intact preparations, gastric activity was more variable than pyloric activity but remained relatively stable across 4 -6 days, and many significant correlations were found between phase and frequency within animals. Decentralized preparations displayed fewer episodes of gastric activity, with altered phase relationships, lower frequencies, and reduced coordination both among gastric units and between the gastric and pyloric rhythms. Together, these results provide insight into the role of neuromodulation in episodic pattern generation and the extent of animal-to-animal variability in features of spontaneously occurring gastric rhythms.

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Presynaptic control of modulatory fibers by their neural network targets

Cited by 77 publications

References 51 publications

Modulation of Oscillator Interactions in the Crab Stomatogastric Ganglion by Crustacean Cardioactive Peptide

Modulation of Oscillator Interactions in the Crab Stomatogastric Ganglion by Crustacean Cardioactive Peptide

Neuropeptide degradation produces functional inactivation in the crustacean nervous system

Consequences of acute and long-term removal of neuromodulatory input on the episodic gastric rhythm of the crabCancer borealis

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