Serotonergic Modulation of Patterned Motor Output in Lymnaea Stagnalis

1988 ◽  
Vol 135 (1) ◽  
pp. 473-486
Author(s):  
M. D. TUERSLEY ◽  
C. R. McCROHAN
Keyword(s):  
Lymnaea Stagnalis ◽  
Rhythmic Activity ◽  
Motor Output ◽  
Buccal Ganglia ◽  
Apparent Decrease ◽  
Inactive Phase ◽  
The Mean ◽  
Timing Of Onset ◽  
Serotonergic Modulation ◽  
Stimulation Of

Rhythmic feeding motor output from the buccal ganglia of Lymnaea stagnalis was evoked by tonic depolarization of the pattern-initiating interneurone SO in the isolated central nervous system. Perfusion with 10−4moll−1 serotonin (5-HT) led to a reduction in frequency of the SO-driven rhythm, and in some cases rhythmic activity was completely blocked. The frequency reduction was predominantly due to an increase in duration of the ‘inactive’ phase of the rhythm. In a number of preparations, the normal buccal rhythm was replaced by an ‘atypical’ pattern of bursting in buccal motoneurones in the presence of 5.HT. This was characterized by the absence of one phase (N2) of interneuronal activity in the feeding pattern generator. Stimulation of the serotonergic giant cerebral interneurones (CGCs), to increase the mean spike frequency from 1.0 to 2.5 Hz, mimicked some of the effects of 5-HT perfusion. However, the timing of onset of CGC stimulation in relation to depolarization of SO was critical; prolonged activation of a CGC led to an apparent decrease in its effectiveness in suppressing the buccal rhythm.

scholarly journals The generation of rhythmic activity in a distributed motor system

1983 ◽  
Vol 102 (1) ◽  
pp. 25-42
Author(s):  
C. S. Cohan ◽  
G. J. Mpitsos
Keyword(s):  
Rhythmic Activity ◽  
Motor Output ◽  
Buccal Ganglion ◽  
Nerve Roots ◽  
Pleurobranchaea Californica ◽  
Buccal Ganglia ◽  
Neuronal Oscillators ◽  
The Brain ◽  
Tonic Stimulation ◽  
Stimulation Of

Rhythmic activity that is distributed to the brain and buccal ganglia and which underlies several types of behaviour, can be evoked from isolated nervous systems of Pleurobranchaea californica by tonic nerve stimulation. The experiments presented here were designed to test whether this rhythmic activity is produced by independent neuronal oscillators located in each ganglion or whether the rhythmic activity arises from a single oscillatory locus in the buccal ganglion and is transmitted passively to the brain. By interrupting the conduction of activity in the cerebrobuccal connectives (CBC) between brain and buccal ganglia we show that motor output from the brain depends on sustained, cycle to cycle input from the buccal ganglion and cannot be reset with respect to the buccal activity. The production of rhythmic activity in the brain depends on the generation of rhythmic activity in the buccal ganglia whether the rhythms are activated by stimulation of buccal roots or paracerebral command cells in the brain. Simultaneous intracellular recordings from brain motoneurones and buccal interneurones which project to the brain indicate that these interneurones provide both the drive and the pattern for rhythmic motor output in the brain. Tonic stimulation of the CBC can produce rhythmic activity in isolated brains in which all nerve roots and connectives have been cut. This can be explained by the fact that tonic stimulation of the connectives is transformed into phasic activity by the axons within the connective. We conclude therefore, that rhythmic, coordinated activity in the brain and buccal ganglia of Pleurobranchaea arises from oscillatory circuits that are located only in the buccal ganglia.

scholarly journals Properties of Ventral Cerebral Neurones Involved in the Feeding System of the Snail, Lymnaea Stagnalis

1984 ◽  
Vol 108 (1) ◽  
pp. 257-272
Author(s):  
C. R. MCCROHAN
Keyword(s):  
Lymnaea Stagnalis ◽  
Rhythmic Activity ◽  
Cell Types ◽  
Feeding System ◽  
Oral Aperture ◽  
Axonal Projections ◽  
Cerebral Ganglia ◽  
Buccal Ganglia ◽  
Relationship Of ◽  
The Relationship

Four identified neurone types (CV3, 7, 5 and 6), located in the ventral cerebral ganglia of Lymnaea stagnalis, are described. These cells have axonal projections in one or more of the nerves innervating the lips. In addition, they show rhythmic synaptic inputs leading to strong burst activity in phase with cyclic output from the buccal ganglia, suggesting a role in the control of the oral aperture during feeding. The innervation of lip muscle by one of the cell types (CV7) is confirmed electrophysiologically. The relationship of rhythmic activity in CV cells with that in the buccal feeding system is discussed.

Cerebral Interneurones Controlling Feeding Motor Output In The Snail Lymnaea Stagnalis

1989 ◽  
Vol 147 (1) ◽  
pp. 361-374
Author(s):  
CATHERINE R. McCROHAN ◽  
MICHAEL A. KYRIAKIDES
Keyword(s):  
Central Pattern Generator ◽  
Lymnaea Stagnalis ◽  
Pattern Generator ◽  
Motor Output ◽  
Excitatory Postsynaptic Potentials ◽  
Gastropod Species ◽  
Postsynaptic Potentials ◽  
Inhibitory Postsynaptic Potentials ◽  
Buccal Ganglia

1. The cerebral ventral 1 (CV1) interneurones of Lymnaea occurred as a population of at least three in each ganglion, all with similar morphologies. Steady depolarization of a CV1 cell led to initiation and maintenance of rhythmic feeding motor output from the buccal ganglia. 2. CV1 interneurones produced facilitating excitatory postsynaptic potentials in Nl interneurones of the buccal central pattern generator for feeding. Connections with N2 interneurones were not found. 3. The CV1 population could be separated into two subgroups. CVla received strong synaptic feedback in phase with the buccal rhythm, leading to strong bursting during generation of feeding motor output. CVlb received only weak feedback, and often fired continuously when depolarized. 4. Unitary inhibitory postsynaptic potentials were characteristic of all CV1 neurones, but were only visible in CVlb when it was depolarized. These inputs are thought to arise indirectly from the buccal central pattern generator. 5. The CV1 population is probably homologous with similar neurones in other gastropod species.

Esophageal mechanoreceptors in the feeding system of the pond snail, Lymnaea stagnalis

1989 ◽  
Vol 61 (4) ◽  
pp. 727-736 ◽  
Author(s):  
C. J. Elliott ◽  
P. R. Benjamin
Keyword(s):  
Feeding Behavior ◽  
Synaptic Input ◽  
Lymnaea Stagnalis ◽  
Esophageal Wall ◽  
Pond Snail ◽  
Feeding System ◽  
Buccal Ganglia ◽  
Feeding Rhythm ◽  
Feeding Cycle ◽  
Stimulation Of

1. We identify esophageal mechanoreceptor (OM) neurons of Lymnaea with cell bodies in the buccal ganglia and axons that branch repeatedly to terminate in the esophageal wall. 2. The OM cells respond phasically to gut distension. Experiments with a high magnesium/low calcium solution suggest that the OM neurons are primary mechanoreceptors. 3. In the isolated CNS preparation, the OM cells receive little synaptic input during the feeding cycle. 4. The OM cells excite the motoneurons active in the rasp phase of the feeding cycle. 5. The OM cells inhibit each of the identified pattern-generating and modulatory interneurons in the buccal ganglia. Experiments with a saline rich in magnesium and calcium suggest that the connections are monosynaptic. 6. Stimulation of a single OM cell to fire at 5-15 Hz is sufficient to terminate the feeding rhythm in the isolated CNS preparation. 7. We conclude that these neurons play a role in terminating feeding behavior.

scholarly journals Initiation of Feeding Motor Output by an Identified Interneurone in the Snail Lymnaea Stagnalis

1984 ◽  
Vol 113 (1) ◽  
pp. 351-366
Author(s):  
C. R. MCCROHAN
Keyword(s):  
Lymnaea Stagnalis ◽  
Motor Output ◽  
Synaptic Inputs ◽  
Axonal Projections ◽  
Cerebral Ganglia ◽  
Buccal Ganglia

1. The cerebral ventral 1 (CV1) cells of Lymnaea are located in the cerebral ganglia, and have axonal projections to the buccal ganglia. 2. Maintained depolarization of a CV1 neurone leads to initiation, maintenance and modulation of rhythmic feeding motor output from buccal and cerebral ganglia. 3. The CV1 cells receive rhythmic synaptic inputs, in phase with feeding cycles, which probably originate from buccal rhythm-generating interneurones. 4. CV1 cells initiate feeding cycles independently of the buccal slow oscillator (SO) neurone, previously described. The possible roles of CV1 and SO are discussed.

Interactions of the slow oscillator interneuron with feeding pattern-generating interneurons in Lymnaea stagnalis

1985 ◽  
Vol 54 (6) ◽  
pp. 1412-1421 ◽  
Author(s):  
C. J. Elliott ◽  
P. R. Benjamin
Keyword(s):  
Motor System ◽  
Lymnaea Stagnalis ◽  
Pond Snail ◽  
Excitatory Synapses ◽  
Feeding System ◽  
Buccal Ganglion ◽  
Buccal Ganglia ◽  
Feeding Rhythm ◽  
The Right ◽  
Stimulation Of

We have used intracellular recording from groups of interneurons in the feeding system of the pond snail, Lymnaea stagnalis, to examine the connections of a modulatory interneuron, the slow oscillator (SO), with the network of pattern-generating interneurons (N1, N2, and N3). The SO is an interneuron whose axon branches solely within the buccal ganglia. There is only one such cell in each snail. In half the snails the cell body is in the right buccal ganglion and in the other half in the left buccal ganglion. Stimulation of either the SO or one of the N1 pattern-generating interneurons elicits the feeding rhythm, but of all the buccal neurons, only the SO can drive the feeding rhythm at the frequency seen in the intact snail. The SO makes reciprocal excitatory synapses with the N1 interneurons that drive the protraction of the radula. This ensures strong activation of the feeding system. The SO inhibits the N2 interneurons. Postsynaptic potentials evoked by stimulation of the SO facilitate without spike broadening in the SO. The SO is strongly inhibited by N2 and N3 interneurons, which are active during the retraction phase. This gates any excitatory inputs to the SO, probably preventing protraction of the radula while retraction is underway. The results support the idea of a single interneuron capable of driving a hierarchically organized motor system.

CHROMATOGRAPHY OF THE 17-KETOGENIC STEROIDS IN THE DIAGNOSIS AND CONTROL OF CONGENITAL ADRENAL HYPERPLASIA

1960 ◽  
Vol XXXIII (II) ◽  
pp. 230-250 ◽  
Author(s):  
Eileen E. Hill
Keyword(s):  
Congenital Adrenal Hyperplasia ◽  
List Type ◽  
Adrenal Hyperplasia ◽  
Normal Children ◽  
Paediatric Practice ◽  
The Mean ◽  
Cortisone Therapy ◽  
And Control ◽  
Clinical Problems ◽  
Stimulation Of

ABSTRACT A method for the fractionation of the urinary 17-ketogenic steroids with no oxygen grouping at C11 and those oxygenated at C11, is applied to the clinical problems of congenital adrenal hyperplasia. In normal children the mean ratio of the non-oxygenated to oxygenated steroids is 0.24. In childrern with congenital adrenal hyperplasia the ratio is 2.3. The reason for this difference in ratio is discussed. The changes in ratio found under stimulation of the adrenal gland with exogenous or endogenous corticotrophin and the suppression with cortisone therapy are studied. This test can be applied to isolated samples of urine, a major advantage in paediatric practice, and can be carried out in routine laboratories. It is found to be reliable in the diagnosis and sensitive in the control of congenital adrenal hyperplasia.

Deep brain stimulation of the posterior limb of the internal capsule in the treatment of central poststroke neuropathic pain of the lower limb: case series with long-term follow-up and literature review

2020 ◽  
Vol 133 (3) ◽  
pp. 830-838 ◽  
Author(s):  
Andrea Franzini ◽  
Giuseppe Messina ◽  
Vincenzo Levi ◽  
Antonio D’Ammando ◽  
Roberto Cordella ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Lower Limb ◽  
Internal Capsule ◽  
Posterior Limb ◽  
Vas Score ◽  
The Mean ◽  
Deep Brain ◽  
Stimulation Of

OBJECTIVECentral poststroke neuropathic pain is a debilitating syndrome that is often resistant to medical therapies. Surgical measures include motor cortex stimulation and deep brain stimulation (DBS), which have been used to relieve pain. The aim of this study was to retrospectively assess the safety and long-term efficacy of DBS of the posterior limb of the internal capsule for relieving central poststroke neuropathic pain and associated spasticity affecting the lower limb.METHODSClinical and surgical data were retrospectively collected and analyzed in all patients who had undergone DBS of the posterior limb of the internal capsule to address central poststroke neuropathic pain refractory to conservative measures. In addition, long-term pain intensity and level of satisfaction gained from stimulation were assessed. Pain was evaluated using the visual analog scale (VAS). Information on gait improvement was obtained from medical records, neurological examination, and interview.RESULTSFour patients have undergone the procedure since 2001. No mortality or morbidity related to the surgery was recorded. In three patients, stimulation of the posterior limb of the internal capsule resulted in long-term pain relief; in a fourth patient, the procedure failed to produce any long-lasting positive effect. Two patients obtained a reduction in spasticity and improved motor capability. Before surgery, the mean VAS score was 9 (range 8–10). In the immediate postoperative period and within 1 week after the DBS system had been turned on, the mean VAS score was significantly lower at a mean of 3 (range 0–6). After a mean follow-up of 5.88 years, the mean VAS score was still reduced at 5.5 (range 3–8). The mean percentage of long-term pain reduction was 38.13%.CONCLUSIONSThis series suggests that stimulation of the posterior limb of the internal capsule is safe and effective in treating patients with chronic neuropathic pain affecting the lower limb. The procedure may be a more targeted treatment method than motor cortex stimulation or other neuromodulation techniques in the subset of patients whose pain and spasticity are referred to the lower limbs.

scholarly journals Effect of a Neuropeptide Gene on Behavioral States in Caenorhabditis elegans Egg-Laying

Genetics ◽  
2000 ◽  
Vol 154 (3) ◽  
pp. 1181-1192 ◽  
Author(s):  
Laura E Waggoner ◽  
Laura Anne Hardaker ◽  
Steven Golik ◽  
William R Schafer
Keyword(s):  
Caenorhabditis Elegans ◽  
Active Phase ◽  
Egg Laying ◽  
Sensory Cues ◽  
Nematode Caenorhabditis Elegans ◽  
Inactive State ◽  
Recessive Mutations ◽  
Inactive Phase ◽  
Behavioral States ◽  
Stimulation Of

Abstract Egg-laying behavior in the nematode Caenorhabditis elegans involves fluctuation between alternative behavioral states: an inactive state, during which eggs are retained in the uterus, and an active state, during which eggs are laid in bursts. We have found that the flp-1 gene, which encodes a group of structurally related neuropeptides, functions specifically to promote the switch from the inactive to the active egg-laying state. Recessive mutations in flp-1 caused a significant increase in the duration of the inactive phase, yet egg-laying within the active phase was normal. This pattern resembled that previously observed in mutants defective in the biosynthesis of serotonin, a neuromodulator implicated in induction of the active phase. Although flp-1 mutants were sensitive to stimulation of egg-laying by serotonin, the magnitude of their serotonin response was abnormally low. Thus, the flp-1-encoded peptides and serotonin function most likely function in concert to facilitate the onset of the active egg-laying phase. Interestingly, we observed that flp-1 is necessary for animals to down-regulate their rate of egg-laying in the absence of food. Because flp-1 is known to be expressed in interneurons that are postsynaptic to a variety of chemosensory cells, the FLP-1 peptides may function to regulate the activity of the egg-laying circuitry in response to sensory cues.

Comparison of the Renin Response to Dopamine and Noradrenaline in Normal Subjects and Patients with Autonomic Insufficiency

1974 ◽  
Vol 46 (4) ◽  
pp. 481-488 ◽  
Author(s):  
C. S. Wilcox ◽  
M. J. Aminoff ◽  
A. B. Kurtz ◽  
J. D. H. Slater
Keyword(s):  
Autonomic Failure ◽  
Sodium Intake ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Control Groups ◽  
Autonomic Reflexes ◽  
Fractional Increase ◽  
The Mean ◽  
Autonomic Insufficiency ◽  
Stimulation Of

1. The effect on plasma renin activity (PRA) of dopamine and noradrenaline infusions was studied in three patients with Shy—Drager syndrome, three patients with Parkinson's disease and normal autonomic reflexes, and three healthy volunteers. The patients with the Shy—Drager syndrome had functional evidence of a peripheral lesion of the sympathetic nervous system and subnormal PRA on a controlled sodium intake. 2. In all subjects catecholamines were infused step-wise for 4 min until a 30% rise in systolic blood pressure occurred. 3. In each subject, PRA fell after noradrenaline but rose after dopamine. The mean fractional increase in PRA after dopamine was no less in the Shy—Drager patients than in the control groups. 4. The results suggest, first, that stimulation of dopamine receptors can release renin, and secondly, that inadequate renin stores cannot explain the low PRA found in our patients with autonomic failure.

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