Photoperiodic control of electrophysiological properties of the caudo‐dorsal cells in the pond snail, Lymnaea stagnalis

2021 ◽  
Author(s):  
Yoshitaka Hamanaka ◽  
Sakiko Shiga
Keyword(s):  
Lymnaea Stagnalis ◽  
Pond Snail ◽  
Photoperiodic Control ◽  
Electrophysiological Properties ◽  
Dorsal Cells

Integration of biphasic synaptic input by electrotonically coupled neuroendocrine caudodorsal cells in the pond snail

1983 ◽  
Vol 49 (6) ◽  
pp. 1392-1409 ◽  
Author(s):  
A. ter Maat ◽  
E. W. Roubos ◽  
J. C. Lodder ◽  
P. Buma
Keyword(s):  
Synaptic Input ◽  
Lymnaea Stagnalis ◽  
Electrical Coupling ◽  
Pond Snail ◽  
Excitatory Postsynaptic Potential ◽  
Postsynaptic Potential ◽  
Electrophysiological Recordings ◽  
Coupled Cells ◽  
Lateral Branches ◽  
Dorsal Cells

The ovulation hormone-producing caudodorsal cells (CDCs) of the pond snail Lymnaea stagnalis form two clusters of electrotonically coupled cells, each containing a few specialized (ventral) cells that connect the clusters. The hormone is secreted during a pacemaker-driven discharge. The CDCs receive a biphasic cholinergic postsynaptic potential (PSP), consisting of a rapid excitatory postsynaptic potential (EPSP) and a slow inhibitory postsynaptic potential (IPSP) that is elicited by stimulation of nerves. The effect of the synaptic input on the discharge of the CDCs is described and the location of the synapse investigated by a combination of electrophysiological recordings and morphological techniques. The PSP interrupts the discharge and hastens its termination. In addition, it causes a reversal of the temporal order of the spikes of ventral cells (that normally lead) and dorsal cells (that lead only after the PSP). Ion-substitution experiments indicate that the ionic mechanism underlying the biphasic PSP is conventional, involving a conductance increase for Na+ (EPSP) and K+ (IPSP). Receptors mediating the inhibitory component occur only on the proximal axons of the ventral cells, both components are larger and reverse more readily in ventral cells. These findings suggest that the PSP is generated in the ventral cells. The biphasic PSP has no effect on electrical coupling, suggesting that it is not generated along the electrical pathways among the cells. Horseradish peroxidase (HRP) staining reveals that the lateral branches emerge from the proximal axons of the ventral cells only. In HRP-filled preparations processed for electron microscopy (EM) acetylcholinesterase is demonstrated at these branches where it occurs associated with synapses. The location on fine branches of the ventral cells explains the absence of an effect on electrotonic transmission, whereas the reluctance of components of the PSP to reverse at the expected potentials is due to the distribution of the synapses over more than one cell. It is concluded that the biphasic PSP is received only by the ventral cells and that it is conveyed electrotonically to the other cells.

scholarly journals Green Tea-Derived Catechins have Beneficial Effects on Cognition in the Pond Snail

2021 ◽  
Author(s):  
Yoshimasa Komatsuzaki ◽  
Ayaka Itoh ◽  
Minoru Saito
Keyword(s):  
Green Tea ◽  
Lymnaea Stagnalis ◽  
Model System ◽  
Long Term Memory ◽  
Pond Snail ◽  
Electrophysiological Properties ◽  
Beneficial Effects ◽  
Respiratory Behavior ◽  
Activity Dependent

Green tea has been used as a medicine in East Asia for thousands of years. Plant-derived compounds called flavanols, which are included in green tea, may have potentials to help maintain healthy brain function. In this chapter, we review the effects of flavanols, e.g. epicatechin (EpiC), on cognitive ability in the pond snail, Lymnaea stagnalis. In this decade, the Lukowiak’s group has tested the effects of EpiC on cognition ability in Lymnaea. In a Lymnaea model system, they showed that EpiC and EpiC-containing foods have a rapid and activity-dependent effect enhancing the formation of long-term memory (LTM) following operant conditioning of aerial respiratory behavior. In the last part of this chapter, we also introduce our study for the effects of EpiC on LTM formation in another model system in Lymnaea. This study showed that EpiC increases the persistence of LTM formed by classical conditioning of feeding behavior, and suggested that EpiC alters some electrophysiological properties of a neuron in the feeding system.

scholarly journals A survey of miRNAs involved in biomineralization and shell repair in the freshwater gastropod Lymnaea stagnalis

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Nicolas Cerveau ◽  
Daniel John Jackson
Keyword(s):  
Matrix Protein ◽  
Lymnaea Stagnalis ◽  
Sequence Similarity ◽  
Mature Mirnas ◽  
Pond Snail ◽  
Mrna Levels ◽  
Forming Process ◽  
Rna Molecules ◽  
Freshwater Gastropod ◽  
Shell Matrix

AbstractMicroRNAs (miRNAs) are a deeply conserved class of small, single stranded RNA molecules that post-transcriptionally regulate mRNA levels via several targeted degradation pathways. They are involved in a wide variety of biological processes and have been used to infer the deep evolutionary relationships of major groups such as the Metazoa. Here we have surveyed several adult tissues of the freshwater pulmonate Lymnaea stagnalis (the Great Pond Snail) for miRNAs. In addition we perform a shell regeneration assay to identify miRNAs that may be involved in regulating mRNAs directly involved in the shell-forming process. From seven mature tissues we identify a total of 370 unique precursor miRNAs that give rise to 336 unique mature miRNAs. While the majority of these appear to be evolutionarily novel, most of the 70 most highly expressed (which account for 99.8% of all reads) share sequence similarity with a miRBase or mirGeneDB2.0 entry. We also identify 10 miRNAs that are differentially regulated in mantle tissue that is actively regenerating shell material, 5 of which appear to be evolutionarily novel and none of which share similarity with any miRNA previously reported to regulate biomineralization in molluscs. One significantly down-regulated miRNA is predicted to target Lst-Dermatopontin, a previously characterized shell matrix protein from another freshwater gastropod. This survey provides a foundation for future studies that would seek to characterize the functional role of these molecules in biomineralization or other processes of interest.

Histochemical study on the relation between NO-generative neurons and central circuitry for feeding in the pond snail, Lymnaea stagnalis

1998 ◽  
Vol 32 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Hisayo Sadamoto ◽  
Dai Hatakeyama ◽  
Satoshi Kojima ◽  
Yutaka Fujito ◽  
Etsuro Ito
Keyword(s):  
Lymnaea Stagnalis ◽  
Histochemical Study ◽  
Pond Snail

scholarly journals Sensory mediation of memory blocking stressors in the pond snail Lymnaea stagnalis

2011 ◽  
Vol 214 (15) ◽  
pp. 2528-2533 ◽  
Author(s):  
S. Dalesman ◽  
V. Karnik ◽  
K. Lukowiak
Keyword(s):  
Lymnaea Stagnalis ◽  
Pond Snail

Cholinergic interneurons in the feeding system of the pond snail lymnaea stagnalis. I. cholinergic receptors on feeding neurons

1992 ◽  
Vol 336 (1277) ◽  
pp. 157-166 ◽  
Keyword(s):  
Synaptic Input ◽  
Lymnaea Stagnalis ◽  
Cholinergic Receptors ◽  
Pond Snail ◽  
Feeding System ◽  
Inhibitory Receptor ◽  
Excitatory Response ◽  
Cholinergic Interneurons ◽  
Feeding Rhythm ◽  
Cholinergic Response

All the identified feeding motoneurons of Lymnaea respond to bath or iontophoretically applied acetylcholine (ACh). Three kinds of receptors (one excitatory, one fast inhibitory and one slow inhibitory) were distinguished pharmacologically. The agonist TMA (tetram ethylam m onium ) activates all three receptors, being weakest at the slow inhibitory receptor. PTMA (phenyltrim ethylam monium ) is less potent than TMA and is ineffective at the slow inhibitory receptor, which is the only receptor sensitive to arecoline. At 0.5 mM the antagonists HMT (hexamethonium) and ATR (atropine) selectively block the excitatory response, while PTMA reduces the response to ACh at all three receptors. d-TC (curare) antagonizes only the fast excitatory and the fast inhibitory responses, but MeXCh (methylxylocholine) blocks the fast excitatory and slow inhibitory responses solely. For each of the feeding motoneurons, the sign of the cholinergic response (excitation or inhibition) is the same as the synaptic input received in the N1 phase of the feeding rhythm .

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