The transient potassium outward current has different roles in modulating the pyloric and gastric mill rhythms in the stomatogastric ganglion

2017 ◽  
Vol 203 (4) ◽  
pp. 275-290 ◽  
Author(s):  
Lin Zhu ◽  
Allen I. Selverston ◽  
Joseph Ayers
Keyword(s):  
Outward Current ◽  
Stomatogastric Ganglion ◽  
Gastric Mill

Synaptic regulation of cellular properties and burst oscillations of neurons in gastric mill system of spiny lobsters, Panulirus interruptus

1984 ◽  
Vol 52 (1) ◽  
pp. 54-73 ◽  
Author(s):  
D. F. Russell ◽  
D. K. Hartline
Keyword(s):  
Motor Neurons ◽  
Pattern Generator ◽  
Stomatogastric Ganglion ◽  
Gastric Mill ◽  
Panulirus Interruptus ◽  
Synaptic Regulation ◽  
Gastric Cells ◽  
Current Pulses ◽  
Regenerative Property ◽  
Stimulation Of

The properties of neurons in the stomatogastric ganglion (STG) participating in the pattern generator for the gastric mill rhythm were studied by intracellular current injection under several conditions: during ongoing gastric rhythms, in the nonrhythmic isolated STG, after stimulation of the nerve carrying central nervous system (CNS) inputs to the STG, or under Ba2+ or Sr2+. Slow regenerative depolarizations during ongoing rhythms were demonstrated in the anterior median, cardiopyloric, lateral cardiac, gastropyloric, and continuous inhibitor (AM, CP, LC, GP, and CI) neurons according to criteria such as voltage dependency, burst triggering, and termination by brief current pulses, etc. Experiments showed that regenerative-like behavior was not due to synaptic network interactions. The slow regenerative responses were abolished by isolating the stomatogastric ganglion but could be reestablished by stimulating the input nerve. This indicates that certain CNS inputs synaptically induce the regenerative property in specific gastric neurons. Slow regenerative depolarizations were not demonstrable in gastric mill (GM) motor neurons. Their burst oscillations and firing rate were instead proportional to injected current. CNS inputs evoked a prolonged depolarization in GM motor neurons, apparently by a nonregenerative mechanism. All the gastric cells showed prolonged regenerative potentials under 0.5-1.5 mM Ba2+. We conclude that the gastric neurons of the STG can be divided into three types according to their properties: those with a regenerative capability, a repetitively firing type, and a nonregenerative "proportional" type. The cells are strongly influenced by several types of CNS inputs, including "gastric command fibers."

Mechanisms Underlying Type I mGluR-Induced Activation of Lobster Gastric Mill Neurons

2006 ◽  
Vol 96 (6) ◽  
pp. 3378-3388 ◽  
Author(s):  
Rafael Levi ◽  
Allen I. Selverston
Keyword(s):  
G Protein ◽  
Calcium Release ◽  
Metabotropic Glutamate Receptor ◽  
Cyclopiazonic Acid ◽  
Stomatogastric Ganglion ◽  
Type I ◽  
Gastric Mill ◽  
Concentration Increase ◽  
Cellular Mechanisms ◽  
Excitatory Effect

In addition to ionotropic effects, glutamate and acetylcholine have metabotropic modulatory effects on many neurons. Here we show that in the stomatogastric ganglion of the lobster, glutamate, one of the main ionotropic neurotransmitters, modulates the excitability of gastric mill neurons. The neurons in this well-studied system produce rhythmic output to a subset of lobster foregut muscles. Recently, metabotropic glutamate receptor (mGluR) agonists were suggested as modulators of the rhythmic output, in addition to the previously described muscarinic modulation by acetylcholine. However, the cellular mechanisms responsible for these effects on the pattern are not known. Using intracellular recording methods and calcium imaging, we show that glutamate has an excitatory effect on specific neurons in the stomatogastric ganglion, which is mediated by mGluRs. Responses to the application of mGluR type I agonists are transient oscillations in the system, probably arising from network interactions. We show that the excitatory effect is sensitive to phospholipase-C and IP3 and is G-protein dependent. The G-protein dependency was demonstrated by GDPβS and GTPγS injection into identified neurons. The depolarizations and oscillations were accompanied by an increase of intracellular Ca2+ levels and correlated Ca2+ oscillations. By using cyclopiazonic acid, an endoreticular Ca2+ uptake inhibitor, we show that some internal calcium release may augment the response, but is not crucial for its production. Interestingly, although Ca2+ concentration increase is typically associated with the phosphoinositide pathway, in the lobster, the Ca2+ concentration increase—either voltage dependent or independent—cannot account for the observed depolarization.

Motor patterns in the stomatogastric ganglion of the lobster Panulirus argus

1975 ◽  
Vol 62 (2) ◽  
pp. 405-420
Author(s):  
D. K. Hartline ◽  
D. M. Maynard
Keyword(s):  
Stomatogastric Ganglion ◽  
Panulirus Argus ◽  
Complex Pattern ◽  
Gastric Mill ◽  
Motor Patterns ◽  
Antagonistic Muscles

1. Acitivity patterns arising from the thirty cells of the stomatogastric ganglion of Panulirus argus are described for both a semi-intact preparation and an isolated one. 2. The thirty or so cells can be divided so far into two functional groupings: the gastric mill group, with at least ten motor elements, and the pyloric group with at least fourteen. There is some, but not extensive, interaction between groups. 3. The main gastric mill activity is arranged in two sets of elements, each of which is composed of reciprocating elements innervating antagonistic muscles. Thus alternation in activity between the single LC and the two LG neurones results in alternate closing and opening of the lateral teeth; alternation between the four GM and single CP units results in alternate protraction and retraction of the medial tooth. 4. The two sets are phased to each other in such a way that they cause gastric mill teeth to operate effectively to masticate food. 5. The main pyloric activity is arranged in a three-part cycle with each of three sets of units active in sequence. Activity in two PD and one AB unit is followed by bursts in IC and LP units followed in turn by activity in up to seven PY units. Activity in a single VD neurone is locked to this cycle in a more complex pattern.

Serotonergic/cholinergic muscle receptor cells in the crab stomatogastric nervous system. II. Rapid nicotinic and prolonged modulatory effects on neurons in the stomatogastric ganglion

1989 ◽  
Vol 62 (2) ◽  
pp. 571-581 ◽  
Author(s):  
P. S. Katz ◽  
R. M. Harris-Warrick
Keyword(s):  
Motor Neurons ◽  
Preceding Paper ◽  
Stomatogastric Ganglion ◽  
Cell Group ◽  
Muscarinic Antagonists ◽  
Gastric Mill ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Mechanical Coupling ◽  
Plateau Potential

1. The gastropyloric receptor (GPR) cells, which are described in the preceding paper, are a set of proprioceptive cells in the crabs Cancer borealis and Cancer irroratus that contain serotonin (5-hydroxytryptamine, 5-HT) and choline acetyltransferase. These cells have a variety of synaptic effects on cells in the stomatogastric ganglion (STG). We used pharmacologic methods to distinguish the effects that were due to acetylcholine (ACh) from those that could be due to serotonin. 2. The GPR cells evoke excitatory postsynaptic potentials (EPSPs) in two gastric mill motor neurons [lateral and dorsal gastric (LG and DG)] in the stomatogastric ganglion. The EPSPs exhibit nicotinic pharmacology, indicating that they may be due to the release of ACh from the GPR cells. 3. A train of GPR action potentials induces plateau potential properties in the DG motor neuron. This plateau potential induction is not blocked by nicotinic or muscarinic antagonists, suggesting it might be due to serotonin released from the GPR cells. Bath-applied serotonin induces a tonic depolarization of DG with high-intensity spiking. 4. In the accompanying paper, it is shown that DG-evoked muscle contraction leads to the excitation of GPR2 through mechanical coupling of the muscles. Because GPR2 also excites DG, a positive feedback loop exists between GPR2 and DG. This reflex loop may be involved in the control of the medial tooth of the gastric mill. 5. GPR stimulation initiates or enhances rhythmic pyloric cycling. This is due at least in part to a direct enhancement of bursting in the pyloric dilator/anterior burster (PD/AB) pacemaker cell group and can outlast the period of GPR stimulation by up to 1 min. GPR-induced PD burst enhancement continues in the presence of nicotinic and muscarinic antagonists, indicating that the effect is probably not due to the release of ACh. Bath application of serotonin mimicks the neuromodulatory effect of GPR stimulation on the PD/AB group by inducing or enhancing bursting. 6. Thus the GPR cells elicit at least three different synaptic actions in the stomatogastric ganglion: 1) classical, fast nicotinic cholinergic EPSPs that may be important for reflex functions in the gastric mill; 2) noncholinergic, cycle-by-cycle plateau potential induction that might be critical for the timing and operation of the gastric mill, and 3) prolonged, noncholinergic burst enhancement in pyloric neurons that is mimicked by serotonin, lasts many cycles, and may act to assure that the pyloric central pattern generator (CPG) is activated and cycling strongly.

scholarly journals Role of Ih in differentiating the dynamics of the gastric and pyloric neurons in the stomatogastric ganglion of the lobster, Homarus americanus

2016 ◽  
Vol 115 (5) ◽  
pp. 2434-2445 ◽  
Author(s):  
Lin Zhu ◽  
Allen I. Selverston ◽  
Joseph Ayers
Keyword(s):  
Rhythmic Activity ◽  
Homarus Americanus ◽  
Stomatogastric Ganglion ◽  
Phase Plane Analysis ◽  
Heart Cells ◽  
Gastric Mill ◽  
Slow Oscillations ◽  
Cationic Current ◽  
Burst Period

The hyperpolarization-activated inward cationic current ( Ih) is known to regulate the rhythmicity, excitability, and synaptic transmission in heart cells and many types of neurons across a variety of species, including some pyloric and gastric mill neurons in the stomatogastric ganglion (STG) in Cancer borealis and Panulirus interruptus. However, little is known about the role of Ih in regulating the gastric mill dynamics and its contribution to the dynamical bifurcation of the gastric mill and pyloric networks. We investigated the role of Ih in the rhythmic activity and cellular excitability of both the gastric mill neurons (medial gastric, gastric mill) and pyloric neurons (pyloric dilator, lateral pyloric) in Homarus americanus. Through testing the burst period between 5 and 50 mM CsCl, and elimination of postinhibitory rebound and voltage sag, we found that 30 mM CsCl can sufficiently block Ih in both the pyloric and gastric mill neurons. Our results show that Ih maintains the excitability of both the pyloric and gastric mill neurons. However, Ih regulates slow oscillations of the pyloric and gastric mill neurons differently. Specifically, blocking Ih diminishes the difference between the pyloric and gastric mill burst periods by increasing the pyloric burst period and decreasing the gastric mill burst period. Moreover, the phase-plane analysis shows that blocking Ih causes the trajectory of slow oscillations of the gastric mill neurons to change toward the pyloric sinusoidal-like trajectories. In addition to regulating the pyloric rhythm, we found that Ih is also essential for the gastric mill rhythms and differentially regulates these two dynamics.

Properties of synapses made by IVN command-interneurones in the stomatogastric ganglion of the spiny lobster Panulirus interruptus

1982 ◽  
Vol 97 (1) ◽  
pp. 153-168
Author(s):  
K. A. Sigvardt ◽  
B. Mulloney
Keyword(s):  
Membrane Potential ◽  
High Frequency ◽  
Spiny Lobster ◽  
Postsynaptic Membrane ◽  
Stomatogastric Ganglion ◽  
Gastric Mill ◽  
Panulirus Interruptus ◽  
Postsynaptic Potential ◽  
Lateral Posterior ◽  
Conductance Increase

1. The IVN command interneurones synapse directly onto 11 identified neurones in the stomatogastric ganglion: the two pyloric dilators (PDs), the anterior burster (AB), ventricular dilator (VD), the four gastric mill neurones (GMs), the two lateral posterior gastric neurones (LPGNs), and Interneurone I (Int 1). 2. The IVN p.s.p.s in PD and AB are biphasic, and consist of a fast depolarizing component followed by a slower hyperpolarizing component. 3. The hyperpolarizing component of this biphasic postsynaptic potential is inhibitory, and appears to be the result of a conductance increase to K+ and Cl-. 4. The IVN p.s.p. in VD is excitatory and can drive VD one-for-one. 5. The IVN p.s.p.s in GM and LPGN are inhibitory. The amplitude of a single p.s.p. is small but, at high frequency, summation of p.s.p.s holds the postsynaptic membrane potential below threshold. 6. The facilitation characteristics of the p.s.p.s in each neurone are described. 7. The functional significance of these synaptic characteristics is discussed in terms of the modification of motor output caused by a burst of the IVN interneurones.

Contribution of individual ionic currents to activity of a model stomatogastric ganglion neuron

1992 ◽  
Vol 67 (2) ◽  
pp. 341-349 ◽  
Author(s):  
J. Golowasch ◽  
F. Buchholtz ◽  
I. R. Epstein ◽  
E. Marder
Keyword(s):  
Action Potential ◽  
Model Neuron ◽  
Outward Current ◽  
Rhythmic Activity ◽  
Stomatogastric Ganglion ◽  
Delayed Rectifier ◽  
Maximal Conductance ◽  
Action Potential Frequency ◽  
Potential Frequency

1. The behavior of the mathematical model for the lateral pyloric (LP) neuron of the crustacean stomatogastric ganglion (STG) developed in the previous paper was further studied. 2. The action of proctolin, a neuromodulatory peptide that acts directly on the LP neuron, was modeled. The effect of the proctolin-activated current (iproc) on the model neuron mimics the effects of proctolin on the isolated biological LP neuron. The depolarization and increased frequency of firing seen when iproc is activated are associated with changes in the relative contributions of the delayed rectifier (id) and the Ca(2+)-activated outward current (io(Ca] to the repolarization phase of the action potential. 3. The effects of turning off the A-current (iA) in the model were compared with those obtained by pharmacologically blocking iA in the biological neuron. iA appears to regulate action-potential frequency as well as postinhibitory rebound activity. 4. The role of iA on the rhythmic activity of the cell was studied by modifying several of its parameters while periodically activating a simulated synaptically activated conductance, isyn. 5. The effects of manipulations of the maximal conductances (g) for id and io(Ca) were studied. id strongly influences action-potential frequency, whereas io(Ca) strongly influences action-potential duration. 6. Modifications of the maximal conductance of the inward Ca2+ current (iCa) were compared with the effects of blocking iCa in the real cell. 7. The role of the hyperpolarization-activated inward current (ih) during ongoing rhythmic activity was assessed by periodically activating isyn while modifying ih.

RPCH Modulation of a Multi-Oscillator Network: Effects on the Pyloric Network of the Spiny Lobster

2001 ◽  
Vol 85 (4) ◽  
pp. 1424-1435 ◽  
Author(s):  
Patsy S. Dickinson ◽  
Jane Hauptman ◽  
John Hetling ◽  
Anand Mahadevan
Keyword(s):  
Network Effects ◽  
Spiny Lobster ◽  
Motor Pattern ◽  
Stomatogastric Ganglion ◽  
Synaptic Connections ◽  
Gastric Mill ◽  
Red Pigment ◽  
Pyloric Network ◽  
Postinhibitory Rebound ◽  
Oscillator Network

The neuropeptide red pigment concentrating hormone (RPCH), which we have previously shown to activate the cardiac sac motor pattern and lead to a conjoint gastric mill-cardiac sac pattern in the spiny lobster Panulirus, also activates and modulates the pyloric pattern. Like the activity of gastric mill neurons in RPCH, the pattern of activity in the pyloric neurons is considerably more complex than that seen in control saline. This reflects the influence of the cardiac sac motor pattern, and particularly the upstream inferior ventricular (IV) neurons, on many of the pyloric neurons. RPCH intensifies this interaction by increasing the strength of the synaptic connections between the IV neurons and their targets in the stomatogastric ganglion. At the same time, RPCH enhances postinhibitory rebound in the lateral pyloric (LP) neuron. Taken together, these factors largely explain the complex pyloric pattern recorded in RPCH in Panulirus.

Mathematical model of an identified stomatogastric ganglion neuron

1992 ◽  
Vol 67 (2) ◽  
pp. 332-340 ◽  
Author(s):  
F. Buchholtz ◽  
J. Golowasch ◽  
I. R. Epstein ◽  
E. Marder
Keyword(s):  
Preceding Paper ◽  
Outward Current ◽  
Ionic Currents ◽  
Stomatogastric Ganglion ◽  
Delayed Rectifier ◽  
Cancer Borealis ◽  
Similar Action ◽  
Steady State Current ◽  
Voltage Dependent ◽  
Rock Crab

1. The ionic currents in the lateral pyloric (LP) cell of the stomatogastric ganglion (STG) described in the preceding paper of the rock crab Cancer borealis were fit with a set of differential equations that describe their voltage, time, and Ca2+ dependence. The voltage-dependent currents modeled are a delayed rectifier-like current, id; a Ca(2+)-activated outward current, io(Ca); a transient A-like current, iA; a Ca2+ current, iCa; an inwardly rectifying current, ih; and a fast tetrodotoxin (TTX)-sensitive Na+ current, iNa. 2. A single-compartment, isopotential model of the LP cell was constructed from the six voltage-dependent currents, a voltage-independent leak current il, a Ca2+ buffering system, and the membrane capacitance. 3. The behavior of the model LP neuron was compared with that of the biological neuron by simulating physiological experiments carried out in both voltage-clamp and current-clamp modes. The model and biological neurons show similar action-potential shapes, durations, steady-state current-voltage (I-V) curves, and respond to injected current in a comparable way.

Sign in / Sign up

Export Citation Format

Share Document