Structure and Synaptic Activation of the Fast Coxal Depressor Motoneurone of the Cockroach, Periplaneta Americana

1972 ◽  
Vol 56 (3) ◽  
pp. 647-656
Author(s):  
J. F. ILES
Keyword(s):  
Cell Body ◽  
Periplaneta Americana ◽  
Excitatory Input ◽  
Synaptic Activation ◽  
Synaptic Response ◽  
Metathoracic Ganglion ◽  
Procion Yellow ◽  
Giant Fibres

1. Using Procion Yellow dye injection the structure of the fast coxal depressor motoneurone was determined. 2. The cell body of the slow depressor motoneurone was located within the metathoracic ganglion. 3. Intracellular records from the fast motoneurone failed to reveal any post-synaptic response when the largest abdominal giant fibres were stimulated. 4. Smaller abdominal afferent fibres gave an excitatory input.

Specific Re-Innervation of Limbs Transplanted between Segments in the Cockroach, Periplaneta Americana

1972 ◽  
Vol 57 (2) ◽  
pp. 305-309
Author(s):  
D. YOUNG
Keyword(s):  
Cell Body ◽  
Motor Neurons ◽  
Periplaneta Americana ◽  
Thoracic Ganglia ◽  
Morphological Criteria ◽  
Procion Yellow ◽  
Limb Muscles ◽  
Intracellular Stimulation

1. The connexions of single, identified motor neurons have been studied in the thoracic ganglia of the cockroach, Periplaneta americana. Selected cell bodies were identified on purely morphological criteria from one animal to another. Similarly, serially homologous cell bodies were identified from one ganglion to another. Their connexions to particular limb muscles were demonstrated by intracellular stimulation through the cell body and infsequent marking with procion yellow dye. 2. Serially homologous cell bodies in the mesothoracic and metathoracic ganglia innervate serially homologous muscles in the mesothoracic and metathoracic limbs. 3. Metathoracic limbs transplanted to the mesothoracic segment retain their metathoracic characteristics. They become functionally incorporated in the mesothoracic segment and are used normally during walking movements. 4. These transplanted metathoracic limbs become re-innervated from the mesothoracic ganglion. Identified mesothoracic cell bodies make specific connexions with those metathoracic muscles which are the serial homologues of their own muscles.

scholarly journals A GABAB receptor on an identified insect motor neurone

1995 ◽  
Vol 198 (4) ◽  
pp. 889-894
Author(s):  
D Bai ◽  
D Sattelle
Keyword(s):  
Cell Body ◽  
Periplaneta Americana ◽  
Gabab Receptor ◽  
Reversal Potential ◽  
Motor Neurone ◽  
Induced Responses ◽  
K Channels ◽  
Metathoracic Ganglion

The vertebrate GABAB receptor (GABABR) agonists 3-aminopropylphosphonous acid (3-APPA), SK&F97541 and 3-aminopropylphosphonic acid (3-APA) are able to induce a hyperpolarization on the cell body of motor neurone Df in the metathoracic ganglion of the cockroach (Periplaneta americana), although the classic vertebrate GABABR agonist l-baclofen fails to induce any responses on the same neurone. Consistent with the findings on vertebrate GABABRs, the 3-APPA-induced responses on Df were also insensitive to the GABAAR antagonists bicuculline and picrotoxin. However, the GABABR antagonists saclofen and CGP35348 also failed to block this GABAB-like response. These results indicate a novel pharmacology for the GABAB-like receptors on the Df neurone. The reversal potential indicates that these GABAB-like receptors may be coupled to K+ channels.

THE HISTOLOGY OF THE GIANT FIBRE SYSTEM IN THE ABDOMINAL VENTRAL NERVE CORD OF THE DESERT LOCUST

1970 ◽  
Vol 102 (9) ◽  
pp. 1163-1168 ◽  
Author(s):  
W. D. Seabrook
Keyword(s):  
Single Cell ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Giant Fibre ◽  
Metathoracic Ganglion ◽  
Giant Fibres ◽  
Giant Fibre System

AbstractSchistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.

The Different Connections and Motor Outputs of Lateral and Medial Giant Fibres in the Crayfish

1971 ◽  
Vol 54 (2) ◽  
pp. 391-404
Author(s):  
JAMES L. LARIMER ◽  
ALAN C. EGGLESTON ◽  
LEONA M. MASUKAWA ◽  
DONALD KENNEDY
Keyword(s):  
High Speed ◽  
Motor Neurone ◽  
Giant Axons ◽  
Procion Yellow ◽  
High Speed Cinematography ◽  
Motor Neurones ◽  
Motor Outputs ◽  
Giant Fibres ◽  
Tonic System ◽  
Stimulation Of

1. High-speed cinematography was used to analyse the abdominal movements of crayfish in response to separate stimulation of medial and lateral giant axons. These films showed that the medial giant fibres command complete abdominal flexions with little flaring of the tail appendages. The lateral giants, in contrast, evoked a relatively weak flexion of the middle abdominal segments, accompanied by promotion of the exopodites of the uropods. 2. An examination of the muscles activated by the two types of giant fibres shows that differences in the connexions between the giant fibres and specific motor neurones can account for the behavioural differences observed. 3. The output of the giant fibres was determined in the sixth abdominal ganglion, where their differential effects are most pronounced. The medial giants activate motor neurones whose axons emerge from root 6 of the sixth ganglion. The lateral giants activate motor neurones whose axons emerge via roots 2 and 3, as well as those emerging via root 6. 4. The larger motor neurones associated with the giant axons in the sixth root of the sixth ganglion have been mapped by Procion Yellow injection, and the terminations of the central giant axons in the sixth ganglion have also been determined. The connexions revealed by this technique are consistent with the physiological findings. 5. The evidence suggests that root 6 of the sixth ganglion is homologous with root 3 of the more anterior ganglia. However, the giant motor neurone of the sixth ganglion has not been identified. 6. The medial and lateral giant fibres, and perhaps other specific ‘command’ interneurones, can thus drive specific ensembles of phasic motor neurones to provide a range of stereotyped quick movements. In this respect the organization of the phasic system of interneurones and motor neurones resembles that in the tonic system.

A Time-Dependent Excitability change in the soma of an identified Insect Motoneurone

1992 ◽  
Vol 162 (1) ◽  
pp. 251-263
Author(s):  
JULES C. HANCOX ◽  
ROBERT M. PITMAN
Keyword(s):  
Cell Body ◽  
Action Potentials ◽  
Periplaneta Americana ◽  
Channel Blocker ◽  
Time Dependent ◽  
Sodium Channel Blocker ◽  
Plateau Potentials ◽  
Excitability Change ◽  
Membrane Oscillations

Long-term, current-clamp recordings were made from the cell body of the fast coxal depressor motoneurone (Df) of the third thoracic ganglion of the cockroach Periplaneta americana. In freshly dissected preparations the response to shortduration, suprathreshold, depolarising current pulses was a graded series of damped membrane oscillations similar to those reported previously in this neurone. The response to current injection changed, however, with increasing time after setting up the preparation: cells developed the ability to exhibit all-ornone action potentials. Their amplitude, however, was usually insufficient to overshoot 0 m V. Our observations suggest that the enhancement in excitability is dependent on time following dissection rather than on time following impalement. Recordings taken from neurone somata mechanically divided from their processes indicated that the time-dependent changes in excitability were not attributable to changes in synaptic input to the neurone and, moreover, that the cell body was involved in action potential genesis. The action potentials were resistant to treatment with the sodium channel blocker tetrodotoxin (up to 10−5 mol l−1), but were reversibly abolished when preparations were bathed in saline containing cadmium ions (1 mmol l−1) or manganese ions (20 or 40 mmol l−1) and, therefore, the inward current underlying these events was largely, if not entirely, carried by calcium ions. These time-dependent action potentials can co-exist with plateau potentials. In neurones giving both plateau potentials and time-dependent action potentials, plateau potentials can drive action potentials in bursts.

Ultrastructure of a sensillum associated with the pharynx of the cockroach Periplaneta americana

1996 ◽  
Vol 74 (11) ◽  
pp. 1999-2008
Author(s):  
R. Gary Chiang ◽  
K. G. Davey
Keyword(s):  
Electron Microscopy ◽  
Cell Body ◽  
Extracellular Space ◽  
Direct Contact ◽  
Periplaneta Americana ◽  
Sensory Cell ◽  
Sensory Cells ◽  
Osmotic Concentration ◽  
Sensory Cilia ◽  
Ultrathin Sections

A sensillum associated with the pharynx of the cockroach Periplaneta americana was examined in serial ultrathin sections using electron microscopy. This sensillum consisted of a group of 10–20 similar sensillar subunits. Each sensillar subunit possessed one 60- to 70-μm long dendritic sheath that made direct contact with the cuticle. The dendritic sheath enclosed 3–5 sensory cilia arising from 3–5 sensory cells located in a cluster approximately 30 μm proximal to the base of the sheath. Between the sensory cell body and the base of the sheath the dendrites were wrapped by the sheath-forming cell. Before entering the dendritic sheath itself, the dendrites crossed through an extracellular space, the ciliary sinus. No cuticular specializations, such as a well-defined sensory hair or pore, were observed. The structure of this sensillum suggests that it responds poorly to mechanical distortion of its surroundings. This characteristic supports the hypothesis that this sensillum measures the osmotic concentration of the ingested food.

Nonspiking interneurons in walking system of the cockroach

1975 ◽  
Vol 38 (1) ◽  
pp. 33-52 ◽  
Author(s):  
K. G. Pearson ◽  
C. R. Fourtner
Keyword(s):  
Membrane Potential ◽  
Periplaneta Americana ◽  
Rhythmic Activity ◽  
Synaptic Activity ◽  
Cobalt Sulfide ◽  
Resting Membrane Potential ◽  
Cellular Mechanisms ◽  
Metathoracic Ganglion ◽  
Nonspiking Interneurons ◽  
Leg Movements

Intracellular recordings were made from the neurites of interneurons and motoneurons in the metathoracic ganglion of the cockroach, Periplaneta americana. Many neurons were penetrated which failed to produce action potentials on the application of large depolarizing currents. Nevertheless, some of them strongly excited and/or inhibited slow motoneurons innervating leg musculature, even with weak depolariziing musculature, even with weak depolarizing currents. Cobalt-sulfide-straining of these nonspiking neurons showed them to be interneurons with their neurites contained entirely within the metathoracic ganglion. Two further characteristics of these interneurons were rapid spontaneous fluctuations in membrane potential and a low resting membrane potential. One nonspiking neuron, interneuron I, when depolarized caused a strong excitation of the set of slow levator motoneurons which discharge in bursts during stepping movements of the metathoracic leg. During rhythmic leg movements the membrane potential of interneuron I oscillated with the depolarizing phases occurring at the same time as bursts of activity in the levator motorneurons. No spiking or any other nonspiking neuron was penetrated which could excite these levator motoneurons. From all these observations we conclude that oscillations in the membrane potential of interneuron I are entirely responsible for producing the levator bursts, and thus for producing stepping movements in a walking animal. During rhythmic leg movements, bursts of activity in levator and depressor motoneurons are initiated by slow graded depolarizations. The similarity of the synaptic activity in these two types of motoneurons suggests that burst activity in the depressor motoneurons is also produced by rhythmic activity in nonspiking interneurons. The fact that no spiking neuron was found to excite the depressor motoneurons supports this conclusion. Interneuron I is also an element of the rhythm-generating system, since short depolarizing pulses applied to it during rhythmic activity could reset the thythm. Long-duration current pulses applied to interneuron I in a quiescent animal did not produce rhythmic activity. This observation, together with the finding that during rhythmic activity the slow depolarizations in interneuron I are usually terminated by IPSPs, suggests that interneuron I alone does not generate the rhythm. No spiking interneurons have yet been enccountered which influence the activity in levator motoneurons. Thus, we conclude that the rhythm is generated in a network of nonspiking interneurons. The cellular mechanisms for generating the oscillations in this network are unknown. Continued.

GABA receptors on the cell-body membrane of an identified insect motor neuron

1988 ◽  
Vol 232 (1269) ◽  
pp. 443-456 ◽  
Keyword(s):  
Motor Neuron ◽  
Cell Body ◽  
Chloride Channel ◽  
Gaba Receptors ◽  
Gaba Receptor ◽  
Periplaneta Americana ◽  
Rank Order ◽  
Chloride Ions ◽  
Resting Membrane Potential ◽  
Induced Current

The pharmacology of a γ-aminobutyric acid (GABA) receptor on the cell body of an identified motor neuron of the cockroach ( Periplaneta americana ) was investigated by current-clamp and voltage-clamp methods. Iontophoretic application of GABA increased membrane conductance to chloride ions, and prolonged application resulted in desensitization. Hill coefficients, determined from dose–response data, indicated that binding of at least two GABA molecules was required to activate the chloride channel. Differences between vertebrate GABA A receptors and insect neuronal GABA receptors were detected. For the GABA receptor of motor neuron D f , the following rank order of potency was observed: isoguvacine > muscimol ≽ GABA > 3-aminopropanesulphonic acid. The GABA B receptor agonist baclofen was inactive. Of the potent vertebrate GABA receptor antagonists (bicuculline, pitrazepin, RU5135 and picrotoxin), only picrotoxin (10 –7 M) produced a potent, reversible block of the response to GABA of motor neuron D f . Both picrotoxinin and picrotin also blocked GABA-induced currents. Bicuculline hydrochloride (10 –4 M) and bicuculline methiodide (10 –4 M) were both ineffective when applied at resting membrane potential (–65 mV), although at hyper-polarized levels partial block of GABA-induced current was sometimes observed. Pitrazepin (10 –4 M) caused a partial, voltage-independent block of GABA-induced current. The steroid derivative RU5135 was inactive at 10 –5 M. In contrast to the potent competitive blockade of vertebrate GABA A receptors by bicuculline, pitrazepin and RU5135, none of the weak antagonism caused by these drugs on the insect GABA receptor was competitive. Flunitrazepam (10 –6 M) potentiated GABA responses, providing evidence for a benzodiazepine site on an insect GABA-receptor–chloride-channel complex.

scholarly journals Nereistoxin: Actions on a CNS Acetylcholine Receptor/Ion Channel in the Cockroach Periplaneta Americana

1985 ◽  
Vol 118 (1) ◽  
pp. 37-52
Author(s):  
D. B. SATTELLE ◽  
I. D. HARROW ◽  
J. A. DAVID ◽  
M. PELHATE ◽  
J. J. CALLEC ◽  
...  
Keyword(s):  
Ion Channel ◽  
Acetylcholine Receptor ◽  
Periplaneta Americana ◽  
Active Form ◽  
Input Resistance ◽  
Postsynaptic Membrane ◽  
Dependent Manner ◽  
Metathoracic Ganglion ◽  
Voltage Dependent ◽  
Giant Interneurone

Nereistoxin hydrogen oxalate (NTX), at low concentrations (in the range 2.0×10−8-10 × 10−6moll−1), induced a dose-dependent partial block of transmission at cereal afferent, giant interneurone synapses in the terminal abdominal ganglion (A6) of the cockroach Periplaneta americana which was not accompanied by changes in either membrane potential or input resistance of the postsynaptic membrane. At a concentration of 1.0 × 10−7 moll−1, NTX suppressed, in a voltage-dependent manner, acetylcholine-induced currents recorded from voltage-clamped cell bodies of both giant interneurone 2 (GI2) in A6, and the fast coxal depressor motoneurone of the metathoracic ganglion (T3). At higher concentrations (in the range 1.0 × 10−5-1.0 × 10−3moll−1) depolarization of the postsynaptic membrane was observed. Axonal depolarization was noted at concentrations above 1.0 × 10−4moll−1. Voltage-clamp experiments showed that the axonal actions of NTX included suppression of sodium and potassium currents and an increase in the membrane leak current. The concentrations of NTX (in the range 1.0 × 10−5-1.0 × 10−3 moll−1) which show the postsynaptic depolarizing effect are in the same range as the NTX concentrations (l.7 × l0−4 and 6.6 × 10−5moll−1) required for 50% inhibition of the binding of 125I-α-bungarotoxin to Periplaneta abdominal nerve cord extracts and Drosophila head extracts, respectively. Thus a potent, voltage-dependent, blocking action of NTX is detected at the CNS acetylcholine receptor/ion channel complex of the cockroach. This, possibly together with the synaptic and axonal depolarizing effects noted at much higher concentrations, may contribute to the mechanism of action of this natural invertebrate neurotoxin which is also the active form of the synthetic insecticide Cartap.

scholarly journals The Identification of Motor Neurones Innervating an Abdominal Ventilatory Muscle in the Locust

1983 ◽  
Vol 107 (1) ◽  
pp. 115-127 ◽  
Author(s):  
QIN-ZHAO YANG
Keyword(s):  
Cell Body ◽  
Contralateral Side ◽  
The Body ◽  
Dorsal Muscle ◽  
The Third ◽  
Metathoracic Ganglion ◽  
Motor Neurones ◽  
Left And Right ◽  
Ventral Muscle ◽  
Ventilatory Muscles

Motor neurones to abdominal ventilatory muscles, with their axons innerve 6 of the metathoracic ganglion of the locust, have been identified by intracellular recording and staining. Three muscles are innervated by the larger branches of this nerve: nerve 6a contains six motor neurones innervating the ventral diaphragm; nerve 6b contains four motor neurones innervating the median internal ventral muscle, and nerve 6d contains five motorneurones innervating the longitudinal dorsal muscle. All motor neuronesinnervate muscles on one side of the body only. Both the median internalventral and the longitudinal dorsal muscles contract during the expiratoryphase of ventilation. Three excitatory motor neurones to the median internalventral muscles spike during expiration whilst the fourth, an inhibitorymotor neurone, is active during both expiration and inspiration. Two of theexcitatory motor neurones have cell bodies in the half of the ganglion ipsilateralto the muscle they innervate. Their neuropilar branches, however, are in both left and right halves of the ganglion. The third excitatory motorneurone has its cell body close to the midline and has most of its neuropilarbranches in the half of the ganglion ipsilateral to its axon. The inhibitorymotor neurone has its cell body just to the contralateral side of the midline, and three distinct areas of neuropilar branches, two contralateral and oneipsilateral to its axon.

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