Morphology and electrophysiology of the ovulation hormone producing neuro-endocrine cells of the freshwater snail Lymnaea stagnalis (L.)

1980 ◽  
Vol 84 (1) ◽  
pp. 259-271
Author(s):  
T. A. de Vlieger ◽  
K. S. Kits ◽  
A. ter Maat ◽  
J. C. Lodder
Keyword(s):  
Endocrine Cells ◽  
Lymnaea Stagnalis ◽  
Cerebral Ganglion ◽  
Cell Types ◽  
Freshwater Snail ◽  
Bag Cells ◽  
Repetitive Electrical Stimulation ◽  
The Right ◽  
Dorsal Cells ◽  
Stimulation Of

The ovulation hormone producing neuro-endocrine cells of Lymnaea stagnalis, the caudo-dorsal cells (CDC), are comparable to the bag cells of Aplysia. Both cell types are capable of the production of a long-lasting activity (afterdischarge) during which an ovulation hormone is released. The CDC (30 cells in the left cerebral ganglion and 70 cells in the right) are usually electrically silent but an afterdischarge can be brought about in all cells of both groups by direct, repetitive electrical stimulation of single CDC. This is not possible in every preparation, indicating that the CDC can be in different states of excitability. All cells participate in the afterdischarge and fire approximately synchronously. All CDC are electrotonically connected. Results of experiments in which neurones were injected with horseradish peroxidase suggest that the demonstrated electrotonic connexions between the two opposite groups of CDC are brought about by 10-12 special axons.

Identification of histaminergic neurons in Aplysia

1990 ◽  
Vol 64 (3) ◽  
pp. 736-744 ◽  
Author(s):  
A. Elste ◽  
J. Koester ◽  
E. Shapiro ◽  
P. Panula ◽  
J. H. Schwartz
Keyword(s):  
Presynaptic Inhibition ◽  
Ganglion Cells ◽  
Lucifer Yellow ◽  
Cerebral Ganglion ◽  
Abdominal Ganglion ◽  
Serotonergic Neuron ◽  
Histaminergic Neurons ◽  
The Central Nervous System ◽  
Bag Cells ◽  
The Right

1. We have identified putative histaminergic neurons in the central nervous system of Aplysia californica by light-microscopic autoradiography after uptake of [3H]histamine and by immunohistochemistry with the use of an antibody specific for histamine. 2. In the cerebral ganglion cells previously shown to contain histamine (C2 and 2 large neighboring cells in the E cluster and a group of smaller cells in the L cluster) were identified both by uptake of [3H]histamine and by histamine immunoreactivity. The identification of C2 was confirmed by experiments in which individual C2s were characterized electrophysiologically and injected with Lucifer yellow before processing for immunohistochemistry. The giant serotonergic neuron did not take up [3H]histamine and was not immunoreactive. 3. In the abdominal ganglion two clusters of cells--one in the left hemiganglion and the other in the right--took up [3H]histamine and were histamine immunoreactive. These clusters are located in the regions occupied by the 30 identified respiratory interneurons, R25 and L25. Individual cells in the R25 and L25 clusters were identified electrophysiologically, marked by injection of Lucifer yellow, and processed for immunocytochemistry. Eleven of the 30 L25 cells examined (from 7 ganglia) and 2 of the 25 R25 cells (from 6 ganglia) that had been marked with Lucifer yellow were also histamine immunoreactive. 4. Also in the abdominal ganglion, identified cells in the L32 cluster were not histamine immunoreactive and did not take up [3H]histamine. These interneurons, which mediate presynaptic inhibition, had previously been considered histaminergic. Neurons in the ganglion known to use transmitters other than histamine (L10, R2, RB cells, and bag cells) were not histamine immunoreactive.(ABSTRACT TRUNCATED AT 250 WORDS)

Vagal cardiac preganglionic neurons: distribution, cell types, and reflex discharges

1982 ◽  
Vol 243 (1) ◽  
pp. R92-R98 ◽  
Author(s):  
S. Nosaka ◽  
K. Yasunaga ◽  
S. Tamai
Keyword(s):  
Vagus Nerve ◽  
Cell Types ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Preganglionic Neurons ◽  
Antidromic Responses ◽  
Group 2 ◽  
Group B ◽  
The Right ◽  
Stimulation Of

In chloralose- and urethan-anesthetized rats, the cardiac branch (CB) of the vagus nerve was electrically stimulated, and antidromic responses of medullary cells were recorded. The cells identified as the vagal cardiac preganglionic neurons (VCPN) were localized in the dorsal motor nucleus (ND group, 8 cells), a region in and around the nucleus ambiguus (NA group, 7 cells) and an intermediary zone (IM group, 2 cells) lying in between. Latencies of the antidromic responses were distinctly different among the three groups, and calculated conduction velocities indicated that the VCPN of the ND group possess C-fiber axons whereas those of the NA group and probably of the IM group, B-fiber axons. In another series of experiments, the right carotid sinus nerve (CSN) or the left cervical vagus nerve was stimulated, and efferent fiber group(s) mediating reflexly evoked discharges to the CB was determined by means of two-point recordings. Among reflex discharges evoked by stimulation of the CSN the shortest latency reflex was proved to be mediated by B-efferent fibers. In contrast, among reflex discharges evoked by stimulation of the vagus nerve, the greatest reflex component was found to be conveyed by C-efferent fibers. It was concluded that the VCPN consist of two types of cells, each located in a different region of the medulla oblongata and contributing to vagal cardiac reflex mechanisms in a different manner.

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.

scholarly journals Operant conditioning of aerial respiratory behaviour in Lymnaea stagnalis

1996 ◽  
Vol 199 (3) ◽  
pp. 683-691 ◽  
Author(s):  
K Lukowiak ◽  
E Ringseis ◽  
G Spencer ◽  
W Wildering ◽  
N Syed
Keyword(s):  
Operant Conditioning ◽  
Tactile Stimulation ◽  
Direct Evidence ◽  
Lymnaea Stagnalis ◽  
Freshwater Snail ◽  
Withdrawal Reflex ◽  
Before And After ◽  
Opening And Closing ◽  
Stimulation Paradigm ◽  
Stimulation Of

In this study, we operantly conditioned the aerial respiratory behaviour of the freshwater snail Lymnaea stagnalis. Aerial respiration in Lymnaea stagnalis is accomplished by the spontaneous opening and closing of its respiratory orifice, the pneumostome, at the water surface. Weak tactile stimulation of the pneumostome area, when the pneumostome is open, evoked only the pneumostome closure response, which is one aspect of the escape-withdrawal reflex. Pneumostome stimulation resulted in its closure and the termination of aerial respiratory activity. A contingent tactile stimulation paradigm was used to operantly condition the animals. Stimulation of the pneumostome whenever the animal attempted to breathe resulted in significantly fewer attempts to open the pneumostome as training progressed. The latency of the first breath (subsequent to stimulation), the number of breaths and the total breathing time were measured before and after each training period. Significant, quantifiable changes in these behavioural parameters were observed only in the operant conditioning group animals. Control animals receiving tactile stimulation to their pneumostome not contingent upon pneumostome opening movements (yoked controls) or those that were physically prevented from surfacing to breathe (hypoxic controls), did not exhibit significant changes in these behavioural parameters. Our data provide the first direct evidence for operant conditioning of respiration in any animal.

The Withdrawal Response of a Freshwater Snail (Lymnaea Stagnalis L.)

1975 ◽  
Vol 62 (3) ◽  
pp. 783-796
Author(s):  
ANTHONY COOK
Keyword(s):  
Electrical Stimulation ◽  
Response Latency ◽  
Lymnaea Stagnalis ◽  
Intact Animal ◽  
Freshwater Snail ◽  
Response Decrement ◽  
Withdrawal Response ◽  
The Brain ◽  
Incremental Process ◽  
Stimulation Of

1. Electrical stimulation of a variety of nerves towards the brain results in movements of the neck of the snail similar to those associated with the withdrawal response of the intact animal. 2. The columellar and cervical nerves mediate most of the movements being measured. 3. Repetition of the stimuli results in a decline in response amplitude which is complicated by a superimposed incremental process which is itself subject to a decremental process as stimuli are repeated. 4. As stimuli are repeated the response latency increases. 5. Consecutive stimulation of pairs of nerves indicates that the response decrement is specific to the nerve being stimulated. 6. The involvement of the pleuro-pedal connectives in the response has been demonstrated both in a semi-intact preparation stimulated electrically and in a free-roaming animal treated surgically and stimulated visually. 7. Visual stimuli associated with the withdrawal response are detected by photoreceptors on the head and in the mantle.

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