scholarly journals Differential neuropeptide modulation of premotor and motor neurons in the lobster cardiac ganglion

2020 ◽  
Vol 124 (4) ◽  
pp. 1241-1256
Author(s):  
Emily R. Oleisky ◽  
Meredith E. Stanhope ◽  
J. Joe Hull ◽  
Andrew E. Christie ◽  
Patsy S. Dickinson
Keyword(s):  
Motor Neurons ◽  
Homarus Americanus ◽  
Cardiac Ganglion ◽  
Differential Distribution

Premotor and motor neurons of the Homarus americanus cardiac ganglion (CG) are normally electrically and chemically coupled, and generate rhythmic bursting that drives cardiac contractions; we show that they can establish independent bursting patterns when physically decoupled by a ligature. The neuropeptide myosuppressin modulates different aspects of the bursting pattern in these neuron types to determine the overall modulation of the intact CG. Differential distribution of myosuppressin receptors may underlie the observed responses to myosuppressin.

Impulse Identification and Axon Mapping of the Nine Neurons in the Cardiac Ganglion of the Lobster Homarus Americanus

1967 ◽  
Vol 47 (2) ◽  
pp. 327-341
Author(s):  
DANIEL K. HARTLINE
Keyword(s):  
Large Cell ◽  
Homarus Americanus ◽  
Simultaneous Recording ◽  
Small Cell ◽  
Complete Analysis ◽  
Cardiac Ganglion ◽  
Cell Identification ◽  
Cell Axon ◽  
Synaptic Interactions ◽  
Stimulation Of

1. Simultaneous recording from several pairs of electrodes placed along the ganglion and certain efferent nerves, during stimulation of other efferents, allows the course of antidromic impulses in each stimulated axon to be mapped. 2. These impulses disappear as they approach their somata, being incapable of invading them, a fact which permits identification of a particular efferent axon with a particular soma. 3. By these means the courses of all such efferent axons, and their corresponding somata, have been determined. These all belong to the five large cells. 4. The impulses from each such axon occurring during the spontaneous burst can be identified, as can impulses from each small cell. 5. Each large-cell axon appears to be inexcitable until it is a few mm from the soma. 6. If the axon branches within this inexcitable region, the branches tend to fire impulses independently. 7. The technique of cell identification opens the way to a more complete analysis of the ganglion's activity and the synaptic interactions which produce it.

Neurohormonal alteration of integrative properties of the cardiac ganglion of the lobster Homarus americanus

1975 ◽  
Vol 63 (1) ◽  
pp. 33-52
Author(s):  
I. M. Cooke ◽  
D. K. Hartline
Keyword(s):  
Impulse Activity ◽  
Homarus Americanus ◽  
Firing Frequency ◽  
Small Cell ◽  
Small Cells ◽  
Cardiac Ganglion ◽  
Cardiac Ganglia ◽  
Length Increase ◽  
Proximal Site ◽  
Intermediate Value

The spontaneous burst discharges of isolated lobster (Homarus americanus) cardiac ganglia were recorded with a spaced array of electrodes. Small regions (less than 1 mm) of the ganglion were exposed to the cardioexcitor neurohormone in extracts of pericardial organs (XPO) or to 10(−5) M 5-hydroxytryptamine (5HT). All axons were excited (increased mean firing frequency, f) by both substances, but only by applications in the region between the soma (but excluding it) and proximal site of impulse initiation. Units not so exposed changed their f relatively little despite f increases of as much as threefold in exposed units and changes in burst rate and overall length. Regularity and grouping of all impulse activity into bursts was never disturbed. 5HT increases burst rate at any point of application. The increases are larger if small cells are affected than if only large cells are exposed. Burst length decreases except when the pacemaker is affected. In contrast, XPO affects neither burst rate or length unless small cells are affected. Length is increased if non-pacemaker small cells are affected; both rate and length increase if the pacemaker is affected. The pacemaker usually exhibits an f of intermediate value. Rate changes are not simply related to its f. A small cell can “burst” in the absence of impulses from any other cells. XPO may enhance endogenous “driver potentials,” while 5HT may excite by depolarizing at limited sites.

scholarly journals Characterization of LAMP1-labeled nondegradative lysosomal and endocytic compartments in neurons

2018 ◽  
Vol 217 (9) ◽  
pp. 3127-3139 ◽  
Author(s):  
Xiu-Tang Cheng ◽  
Yu-Xiang Xie ◽  
Bing Zhou ◽  
Ning Huang ◽  
Tamar Farfel-Becker ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Distribution Patterns ◽  
Confocal Imaging ◽  
Lysosomal Hydrolases ◽  
Differential Distribution ◽  
Gradient Fractionation ◽  
Endocytic Compartments ◽  
Lateral Sclerosis

Despite widespread distribution of LAMP1 and the heterogeneous nature of LAMP1-labeled compartments, LAMP1 is routinely used as a lysosomal marker, and LAMP1-positive organelles are often referred to as lysosomes. In this study, we use immunoelectron microscopy and confocal imaging to provide quantitative analysis of LAMP1 distribution in various autophagic and endolysosomal organelles in neurons. Our study demonstrates that a significant portion of LAMP1-labeled organelles do not contain detectable lysosomal hydrolases including cathepsins D and B and glucocerebrosidase. A bovine serum albumin–gold pulse–chase assay followed by ultrastructural analysis suggests a heterogeneity of degradative capacity in LAMP1-labeled endolysosomal organelles. Gradient fractionation displays differential distribution patterns of LAMP1/2 and cathepsins D/B in neurons. We further reveal that LAMP1 intensity in familial amyotrophic lateral sclerosis–linked motor neurons does not necessarily reflect lysosomal deficits in vivo. Our study suggests that labeling a set of lysosomal hydrolases combined with various endolysosomal markers would be more accurate than simply relying on LAMP1/2 staining to assess neuronal lysosome distribution, trafficking, and functionality under physiological and pathological conditions.

scholarly journals Functional Organization of the Cardiac Ganglion of the Lobster, Homarus americanus

1973 ◽  
Vol 62 (4) ◽  
pp. 448-472 ◽  
Author(s):  
Earl Mayeri
Keyword(s):  
Spike Activity ◽  
Functional Organization ◽  
Large Cell ◽  
Homarus Americanus ◽  
Burst Activity ◽  
Small Cells ◽  
Cardiac Ganglion ◽  
Burst Pattern ◽  
Repetitive Electrical Stimulation ◽  
Stimulation Of

External recording and stimulation, techniques were used to determine which neurons and interactions are essential for production of the periodic burst discharge in the lobster cardiac ganglion. Burst activity can be modulated by brief single shocks applied to the four small cells, but not by similar stimulation of the five large cells, suggesting that normally one or more small cells primarily determine burst rate and duration. Repetitive electrical stimulation of large cells initiates spike activity in small cells, probably via excitatory synaptic and/or electrotonic connections which may normally act to prolong bursts and decrease burst rate. Transection of the ganglion can result in burst activity in small cells in the partial or complete absence of large cell spike activity, but large cells isolated from small cell excitatory synaptic input by transection or by application of dinitrophenol do not burst. Generally, transections which decrease excitatory feedback to small cells are accompanied by an increase in burst rate, but mean spike frequency over an entire burst cycle stabilizes at the original level within 10–30 min for various groups of cells whose spike-initiating sites are still intact. These and previous results suggest that the system is two layered: one or more small cells generate the burst pattern and impose it on the large cells which are the system's motorneurons.

scholarly journals Synergistic plasticity of intrinsic conductance and electrical coupling restores synchrony in an intact motor network

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Brian J Lane ◽  
Pranit Samarth ◽  
Joseph L Ransdell ◽  
Satish S Nair ◽  
David J Schulz
Keyword(s):  
Motor Neurons ◽  
Electrical Coupling ◽  
High Threshold ◽  
Cardiac Ganglion ◽  
Physiological Regulation ◽  
Blocking High ◽  
Motor Network ◽  
Ionic Conductances ◽  
Network Output ◽  
Coupling Conductance

Motor neurons of the crustacean cardiac ganglion generate virtually identical, synchronized output despite the fact that each neuron uses distinct conductance magnitudes. As a result of this variability, manipulations that target ionic conductances have distinct effects on neurons within the same ganglion, disrupting synchronized motor neuron output that is necessary for proper cardiac function. We hypothesized that robustness in network output is accomplished via plasticity that counters such destabilizing influences. By blocking high-threshold K+ conductances in motor neurons within the ongoing cardiac network, we discovered that compensation both resynchronized the network and helped restore excitability. Using model findings to guide experimentation, we determined that compensatory increases of both GA and electrical coupling restored function in the network. This is one of the first direct demonstrations of the physiological regulation of coupling conductance in a compensatory context, and of synergistic plasticity across cell- and network-level mechanisms in the restoration of output.

scholarly journals Abdominal postural motor responses initiated by the muscle receptor organ in lobster depend upon centrally generated motor activity

1992 ◽  
Vol 162 (1) ◽  
pp. 167-183
Author(s):  
S. C. Sukhdeo ◽  
C. H. Page
Keyword(s):  
Motor Activity ◽  
Motor Neurons ◽  
Procambarus Clarkii ◽  
Homarus Americanus ◽  
Abdominal Muscle ◽  
Sensory Response ◽  
Reflex Responses ◽  
Muscle Receptor ◽  
Postural Reflex ◽  
Receptor Organ

1. Stretch stimulation of the abdominal muscle receptor organ of the lobster Homarus americanus initiated spike discharge of its tonic sensory neuron (SR1). This sensory response evoked a series of tonic postural reflex responses in the motor neurons that innervate the superficial extensor and flexor muscles of the abdominal postural system. The type of motor response depended on whether a flexion or extension pattern of spontaneous activity was being generated by the postural efferents. Spontaneous shifts between these centrally generated motor activities completely changed the SR1-evoked reflex responses. 2. During spontaneous centrally initiated flexion activity, tonic SR1 neuron discharge elicited an assistance response that included excitation of a medium-sized flexor excitor (f3) and the peripheral extensor inhibitor (e5), and inhibition of at least one extensor excitor. Neither the other flexor excitors nor the peripheral flexor inhibitor (f5) were affected by SR1 excitation. 3. During spontaneous centrally initiated extension activity, SR1 activity elicited a response that included excitation of the extensor excitors and the flexor peripheral inhibitor (f5) only, f3 and e5 spontaneous activities were unchanged. This response was a resistance reflex, since SR1 discharge normally resulted from an imposed abdominal flexion. 4. The SR1-initiated control of postural motor activity in lobster differs from previously published results in the crayfish Procambarus clarkii.

scholarly journals Dopamine maintains network synchrony via direct modulation of gap junctions in the crustacean cardiac ganglion

2018 ◽  
Author(s):  
Brian J Lane ◽  
Daniel R Kick ◽  
David K Wilson ◽  
Satish S Nair ◽  
David J Schulz
Keyword(s):  
Motor Neurons ◽  
Channel Blocker ◽  
Electrical Coupling ◽  
Membrane Conductance ◽  
Large Cell ◽  
Protective Role ◽  
Cardiac Ganglion ◽  
Junctional Conductance ◽  
Network Synchrony ◽  
Gap Junctional

AbstractAbstract The Large Cell (LC) motor neurons of the crab (C. borealis) cardiac ganglion have variable membrane conductance magnitudes even within the same individual, yet produce identical synchronized activity in the intact network. In our previous study (Lane et al., 2016) we blocked a subset of K+ conductances across LCs, resulting in loss of synchronous activity. In this study, we hypothesized that this same variability of conductances could make LCs vulnerable to desynchronization during neuromodulation. We exposed the LCs to serotonin (5HT) and dopamine (DA) while recording simultaneously from multiple LCs. Both amines had distinct excitatory effects on LC output, but only 5HT caused desynchronized output. We further determined that DA rapidly increased gap junctional conductance. Co-application of both amines induced 5HT-like output, but waveforms remained synchronized. Furthermore, DA prevented desynchronization induced by the K+ channel blocker tetraethylammonium (TEA), suggesting that dopaminergic modulation of electrical coupling plays a protective role in maintaining network synchrony.

Sign in / Sign up

Export Citation Format

Share Document