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.

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."

Characterization of synaptically mediated fast and slow inhibitory processes in piriform cortex in an in vitro slice preparation

1988 ◽  
Vol 59 (5) ◽  
pp. 1352-1376 ◽  
Author(s):  
G. F. Tseng ◽  
L. B. Haberly
Keyword(s):  
Membrane Potential ◽  
Piriform Cortex ◽  
Reversal Potential ◽  
Pyramidal Cells ◽  
Membrane Depolarization ◽  
Resting Membrane Potential ◽  
Excitatory Postsynaptic Potential ◽  
Pentobarbital Sodium ◽  
Postsynaptic Potential ◽  
Conductance Increase

1. Intracellular recordings were obtained from anatomically verified layer II pyramidal cells in slices from rat piriform cortex cut perpendicular to the surface. 2. Responses to afferent and association fiber stimulation at resting membrane potential consisted of a depolarizing potential followed by a late hyperpolarizing potential (LHP). Membrane polarization by current injection revealed two components in the depolarizing potential: an initial excitatory postsynaptic potential (EPSP) followed at brief latency by an inhibitory postsynaptic potential (IPSP) that inverted with membrane depolarization and truncated the duration of the EPSP. 3. The early IPSP displayed the following characteristics suggesting mediation by gamma-aminobutyric acid (GABA) receptors linked to Cl- channels: associated conductance increase, sensitivity to increases in internal Cl- concentration, blockage by picrotoxin and bicuculline, and potentiation by pentobarbital sodium. The reversal potential was in the depolarizing direction with respect to resting membrane potential so that the inhibitory effect was exclusively via current shunting. 4. The LHP had an associated conductance increase and a reversal potential of -90 mV in normal bathing medium that shifted according to Nernst predictions for a K+ potential with changes in external K+ over the range 4.5-8 mM indicating mediation by the opening of K+ channels and ruling out an electrogenic pump origin. 5. Lack of effect of bath-applied 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) or internally applied ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) on the LHP and failure of high amplitude, direct membrane depolarization to evoke a comparable potential, argue against endogenous mediation of the LHP by a Ca2+ activated K+ conductance [gK(Ca)]. However, an apparent endogenously mediated gK(Ca) with a duration much greater than the LHP was observed in a low percent of layer II pyramidal cells. Lack of effect of 8-Br-cAMP also indicates a lack of dependence of the LHP on cAMP. 6. Other characteristics of the LHP that were demonstrated include: a lack of blockage by GABAA receptor antagonists, a probable voltage sensitivity (decrease in amplitude in the depolarizing direction), and an apparent brief onset latency (less than 10 ms) when the early IPSP was blocked by picrotoxin. The LHP was unaffected by pentobarbital sodium when the early IPSP was blocked by picrotoxin. 7. Both the LHP and early IPSP were blocked by low Ca2+/high Mg2+, consistent with disynaptic mediation.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Pattern and reset analysis of the gastric mill rhythm in a spiny lobster, Panulirus interruptus

1985 ◽  
Vol 114 (1) ◽  
pp. 71-98
Author(s):  
D. F. Russell
Keyword(s):  
Spiny Lobster ◽  
Activity Level ◽  
Cycle Period ◽  
Gastric Mill ◽  
Panulirus Interruptus ◽  
Terrestrial Locomotion ◽  
Variable Duration ◽  
Burst Pattern ◽  
Constant Duration

The burst pattern of the gastric mill rhythm was studied by varying its cycle period in in vitro preparations comprising the stomatogastric (STG), oesophageal and (paired) commissural ganglia. Reset tests using intracellular polarization of identified STG neurones showed that the CI, LC, GP and GM cells can all strongly affect the cycle period, and therefore apparently play a role in generating the gastric rhythm. Variation in the cycle period could be obtained by: (i) cutting certain input nerves; (ii) relative coordination between the gastric and oesophageal rhythms; or (iii) intracellular polarization of identified STG cells, especially the LC motoneurone. Variation in the cycle period by any of these means showed that the gastric pattern (in such preparations) comprises two basic alternating phases: a variable-duration ‘powerstroke’ and a constant-duration ‘returnstroke’. The powerstroke is taken to include bursts in the LC, GP and GM motoneurones (since they evoke closing of the gastric mill teeth and mastication of food), along with the interburst intervals of the other cells. The durations of all these events co-varies over a large range, as a linear function of the cycle period. The activity level of neurones bursting during the powerstroke is directly proportional to their burst length, and hence appears to be a basic parameter affecting the cycle period. The returnstroke is taken to include bursts in the CP, AM and LG motoneurones (since they evoke opening and resetting of the gastric mill teeth), along with the interburst intervals of the powerstroke cells. All these events tended to assume a fixed duration. The two-part gastric mill pattern can be analogized to other two-part rhythms, e.g. for terrestrial locomotion, in which the load-bearing phase has a variable duration and accounts for most of the variation in the cycle period whereas the unloaded phase tends to assume a constant duration.

Dopamine Modulates Graded and Spike-Evoked Synaptic Inhibition Independently at Single Synapses in Pyloric Network of Lobster

1998 ◽  
Vol 79 (4) ◽  
pp. 2063-2069 ◽  
Author(s):  
Amir Ayali ◽  
Bruce R. Johnson ◽  
Ronald M. Harris-Warrick
Keyword(s):  
Action Potential ◽  
Spiny Lobster ◽  
Motor Pattern ◽  
Input Resistance ◽  
Stomatogastric Ganglion ◽  
Synaptic Inhibition ◽  
Panulirus Interruptus ◽  
Pyloric Network ◽  
Bath Application ◽  
Postsynaptic Cell

Ayali, Amir, Bruce R. Johnson, and Ronald M. Harris-Warrick. Dopamine modulates graded and spike-evoked synaptic inhibition independently at single synapses in pyloric network of lobster. J. Neurophysiol. 79: 2063–2069, 1998. Bath application of dopamine (DA) modifies the rhythmic motor pattern generated by the pyloric network in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus. Synaptic transmission between network members is an important target of DA action. All pyloric neurons employ both graded transmitter release and action-potential–mediated synaptic inhibition. DA was previously shown to alter the graded synaptic strength of every pyloric synapse. In this study, we compared DA's effects on action-potential–mediated and graded synaptic inhibition at output synapses of the lateral pyloric (LP) neuron. At each synapse the postsynaptic cell tested was isolated from other descending and pyloric synaptic inputs. DA caused a reduction in the size of the LP spike-evoked inhibitory postsynaptic potentials (IPSPs) in the pyloric dilator (PD) neuron. The change in IPSP size was significantly and linearly correlated with DA-induced reduction in the input resistance of the postsynaptic PD neuron. In contrast, graded inhibition, tested in the same preparations after superfusing the stomatogastric ganglion (STG) with tetrodotoxin (TTX), was consistently enhanced by DA. DA shifted the amplitude of spike-evoked IPSPs in the same direction as the alteration of the postsynaptic cell input resistance at two additional synapses tested: DA weakened the LP spike-mediated inhibition of the ventricular dilator (VD) and reduced the VD input resistance, while strengthening the LP → pyloric constrictor (PY) synapse and increasing PY input resistance. As previously reported, graded inhibition was enhanced at these two LP output synapses. We conclude that DA can differentially modulate the spike-evoked and graded components of synapses between members of a central pattern generator network. At the synapses we studied, actions on the presynaptic cell predominate in the modulation of graded transmission, whereas effects on postsynaptic cells predominate in the regulation of spike-evoked IPSPs.

Aminergic modulation in lobster stomatogastric ganglion. II. Target neurons of dopamine, octopamine, and serotonin within the pyloric circuit

1986 ◽  
Vol 55 (5) ◽  
pp. 866-881 ◽  
Author(s):  
R. E. Flamm ◽  
R. M. Harris-Warrick
Keyword(s):  
Neural Circuit ◽  
Lucifer Yellow ◽  
Spiny Lobster ◽  
Motor Pattern ◽  
Preceding Paper ◽  
Cell Types ◽  
Stomatogastric Ganglion ◽  
Synaptic Organization ◽  
Potential Oscillations ◽  
Panulirus Interruptus

In the preceding paper, we describe how dopamine, octopamine, and serotonin modulate the neural circuit generating a well-described motor pattern, the pyloric rhythm of the stomatogastric ganglion in the spiny lobster, Panulirus interruptus. In this paper, we identify the neurons within the pyloric circuit that are directly affected by each amine. We accomplished this by isolating each pyloric neuron from all known synaptic input, using a combination of Lucifer yellow photoinactivation of presynaptic neurons and pharmacological blockade by pyloric neurotransmitters. Dopamine, octopamine, and serotonin were bath applied to the preparation, and the responses of synaptically isolated neurons were recorded. Each amine had a unique constellation of effects on the neurons of the pyloric circuit. Almost every neuron in the circuit was directly affected by each amine. Dopamine and octopamine modulated every neuron, whereas serotonin affected four of the six cell types. Each amine had multiple effects among pyloric neurons including the induction of endogenous rhythmic bursting activity, initiation or enhancement of tonic firing activity, and inhibition accompanied by hyperpolarization. All three amines induced rhythmic bursting in one neuron (the AB neuron), but the form of the underlying slow-wave membrane-potential oscillations was different with octopamine than with dopamine and serotonin. Our knowledge of the effects of each amine on each pyloric neuron, combined with the extensive knowledge of the synaptic organization of the pyloric circuit, has allowed us to explain qualitatively the major aspects of the unique variants of the pyloric motor rhythm that each amine produces in the synaptically intact circuit.

scholarly journals Partial purification, tissue distribution and modulatory activity of a crustacean cholecystokinin-like peptide.

1994 ◽  
Vol 187 (1) ◽  
pp. 181-200 ◽  
Author(s):  
G G Turrigiano ◽  
A Van Wormhoudt ◽  
L Ogden ◽  
A I Selverston
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Spiny Lobster ◽  
Reversed Phase ◽  
Partial Purification ◽  
Dependent Manner ◽  
Gastric Mill ◽  
Panulirus Interruptus ◽  
Dose Dependent ◽  
Cck Antagonist

Reversed-phase chromatography was used to separate several forms of cholecystokinin-like peptides (CCKLP) from the pericardial organs (PCOs) of the spiny lobster Panulirus interruptus. Fast protein liquid chromatography of PCOs, stomatogastric ganglia (STGs) and eyestalks revealed five peaks of CCKLP (peaks A-E) that were common to all three tissues, as well as two additional peaks (peaks F and G) in the STG. Peaks A-E were present in the hemolymph of fed, but not starved, lobsters. The bioactivity of peaks A-E was tested on the gastric mill rhythm of the isolated STG. Only peak E elicited activity. The effects of peak E included activating the gastric mill rhythm in quiescent preparations and strengthening existing rhythms in a dose-dependent manner. Further purification of peak E by high performance liquid chromatography resolved this peak into two immunoreactive peaks, one of which retained its bioactivity. The effects of peak E were blocked by the CCK antagonist proglumide. These results are consistent with a role for peak E in the feeding-induced activation of the gastric mill.

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.

Sensory alteration of motor patterns in the stomatogastric nervous system of the spiny lobster Panulirus interruptus

1982 ◽  
Vol 97 (1) ◽  
pp. 137-152
Author(s):  
K. A. Sigvardt ◽  
B. Mulloney
Keyword(s):  
Spiny Lobster ◽  
Sensory Nerves ◽  
Stomatogastric Nervous System ◽  
Impulse Frequency ◽  
Motor Patterns ◽  
Panulirus Interruptus ◽  
Sensory Axons ◽  
Lateral Posterior ◽  
Different Parts ◽  
Stimulation Of

1. Stretching the pyloric region of the lobster's stomach in a manner that resembles pyloric dilation triggers a prolonged burst of impulses in two interneurones with axons in the inferior ventricular nerve (IVN). The burst is activated in the oesophageal ganglion by sensory axons that traverse the lateral ventricular nerves, the dorsal ventricular nerve and the stomatogastric nerve. These sensory axons do not appear to make synaptic contacts in the stomatogastric ganglion. 2. Electrical stimulation of sensory branches of the pyloric nerve triggers similar bursts in the IVN interneurones. 3. The burst of impulses in the IVN interneurones lasts from 2 to 30 s and the impulse frequency ranges from 10 to 80 Hz in different parts of the burst. Once triggered, burst structure and burst duration are independent of the intensity or duration of stimuli applied to the sensory nerves. 4. These bursts alter both the gastric and pyloric motor patterns. The IVN interneurones make a complex pattern of synapses with stomatogastric neurones. These are: pyloric dilators (PD) - excitation and slow inhibition; ventricular dilator (VD) - excitation; gastric mill (GM) neurones - inhibition; lateral posterior gastric neurones (LPGN) - inhibition; and Interneurone I (Int I) - excitation and slow inhibition. The size of the p.s.p.s at each of these synapses depends on the duration and impulse-frequency of the burst in the presynaptic neurones, which in turn alters the firing patterns of the stomatogastric neurones in various ways.

Evidence for a persistent Na+ conductance in neurons of the gastric mill rhythm generator of spiny lobsters.

1997 ◽  
Vol 200 (12) ◽  
pp. 1795-1807
Author(s):  
R C Elson ◽  
A I Selverston
Keyword(s):  
Neuronal Activity ◽  
Motor Neurons ◽  
Spiny Lobster ◽  
Stomatogastric Ganglion ◽  
Inward Rectification ◽  
K Channel ◽  
Gastric Mill ◽  
Plateau Potentials ◽  
Inward Currents

Evidence for a persistent Na+ conductance was obtained in identified motor neurons of the gastric mill network in the stomatogastric ganglion of the spiny lobster Panulirus interruptus. The cells studied were the lateral gastric and lateral posterior gastric motor neurons, which in vivo control chewing movements of the lateral teeth of the gastric mill. We examined basic cellular properties in the quiescent network of the isolated stomatogastric ganglion. In current-clamp recordings, we found two types of evidence for a persistent Na+ conductance. First, tetrodotoxin-sensitive inward rectification occurred during depolarization from rest to spike threshold. Second, 5 mmol l-1 tetraethylammonium (a K+ channel blocker) induced plateau potentials that persisted in the presence of Mn2+ or a low [Ca2+]0 but were blocked by a low [Na+]0 or 100 nmol l-1 tetrodotoxin. The plateau potentials could drive trains of fast spikes in the motor axon and strong transmitter release at central output synapses within the ganglion. This conductance probably corresponds to the persistent Na+ current, INaP, described in cultured stomatogastric neurons and in neurons from several other preparations. During normal neuronal activity, it may contribute to the prolonged plateau depolarizations and long spike trains typical of motor neuronal activity during gastric rhythm generation. Persistent inward currents of this type are likely to be important in neurons that must fire prolonged bursts in cycle after cycle of rhythmical activity.

KChIP1 and Frequenin Modify shal-Evoked Potassium Currents in Pyloric Neurons in the Lobster Stomatogastric Ganglion

2003 ◽  
Vol 89 (4) ◽  
pp. 1902-1909 ◽  
Author(s):  
Y. Zhang ◽  
J. N. MacLean ◽  
W. F. An ◽  
C. C. Lanning ◽  
R. M. Harris-Warrick
Keyword(s):  
Potassium Current ◽  
Time Course ◽  
Spiny Lobster ◽  
Stomatogastric Ganglion ◽  
K Channel ◽  
Panulirus Interruptus ◽  
Recovery From Inactivation ◽  
Pyloric Dilator ◽  
Ef Hand ◽  
Firing Properties

The transient potassium current ( I A) plays an important role in shaping the firing properties of pyloric neurons in the stomatogastric ganglion (STG) of the spiny lobster, Panulirus interruptus. The shal gene encodes I A in pyloric neurons. However, when we over-expressed the lobster Shal protein by shal RNA injection into the pyloric dilator (PD) neuron, the increased I A had somewhat different properties from the endogenous I A. The recently cloned K-channel interacting proteins (KChIPs) can modify vertebrate Kv4 channels in cloned cell lines. When we co-expressed hKChIP1 with lobster shal in Xenopusoocytes or lobster PD neurons, they produced A-currents resembling the endogenous I A in PD neurons; compared with currents evoked by shal alone, their voltage for half inactivation was depolarized, their kinetics of inactivation were slowed, and their recovery from inactivation was accelerated. We also co-expressed shal in PD neurons with lobster frequenin, which encodes a protein belonging to the same EF-hand family of Ca2+ sensing proteins as hKChIP. Frequenin also restored most of properties of the shal-evoked currents to those of the endogenous A-currents, but the time course of recovery from inactivation was not corrected. These results suggest that lobster shal proteins normally interact with proteins in the KChIP/frequenin family to produce the transient potassium current in pyloric neurons.

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