The action of polymethylene-bistrimethylammonium compounds on the central neuron cholinoreceptors of Limnaea stagnalis (L.) (Gastropoda: Pulmonata)

1980 ◽  
Vol 11 (1) ◽  
pp. 119-126 ◽  
Author(s):  
I.L. Kratskin
Keyword(s):  
Central Neuron ◽  
Limnaea Stagnalis

Sodium Regulation in the Freshwater Mollusc Limnaea Stagnalis (L.) (Gastropoda: Pulmonata)

1970 ◽  
Vol 53 (1) ◽  
pp. 147-163 ◽  
Author(s):  
PETER GREENAWAY
Keyword(s):  
Blood Volume ◽  
Tap Water ◽  
Sodium Concentration ◽  
Sodium Balance ◽  
Uptake Mechanism ◽  
Sodium Influx ◽  
Sodium Uptake ◽  
Limnaea Stagnalis ◽  
Total Body ◽  
Sodium Regulation

1. Sodium regulation in normal, sodium-depleted and blood-depleted snails has been investigated. 2. Limnaea stagnalis has a sodium uptake mechanism with a high affinity for sodium ions, near maximum influx occurring in external sodium concentrations of 1.5-2 mM-Na/l and half maximum influx at 0.25 mM-Na/l. 3. L. stagnalis can maintain sodium balance in media containing 0.025 mM-Na/l. Adaptation to this concentration is achieved mainly by an increased rate of sodium uptake and a fall of 37 % in blood sodium concentration, but also by a reduction of the sodium loss rate and a decrease in blood volume. 4. A loss of 23% of total body sodium is necessary to stimulate increased sodium uptake. This loss causes near maximal stimulation of the sodium uptake mechanism. 5. An experimentally induced reduction of blood volume in L. stagnalis increases sodium uptake to three times the normal level. 6. About 40% of sodium influx from artificial tap water containing 0.35 mM-Na/l into normal snails is due to an exchange component. Similar exchange components of sodium influx were also observed in sodium-depleted and blood-depleted snails in the same external sodium concentration.

Electrophysiology of the Giant Nerve Cell Bodies of Limnaea Stagnalis (L.) (Gastropoda: Pulmonata)

1974 ◽  
Vol 60 (3) ◽  
pp. 653-671
Author(s):  
D. B. SATTELLE
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Cell Types ◽  
Resting Potential ◽  
Constant Field ◽  
Bathing Medium ◽  
Mean Values ◽  
Relative Contribution ◽  
External Potassium ◽  
Limnaea Stagnalis

1. A mean resting potential of -53.3 (S.D. ±2.7) mV has been obtained for 23 neurones of the parietal and visceral ganglia of Limnaea stagnalis (L.). Changes in the resting potential of between 28 and 43 mV accompany tenfold changes in [K+0]. A modified constant-field equation accounts for the behaviour of most cells over the range of external potassium concentrations from 0-5 to 10.o mM/1. Mean values have been estimated for [K+1, 56.2 (S.D.± 9-0) mM/1 and PNa/PK, 0-117 (S.D.±0-028). 2. Investigations on the ionic basis of action potential generation have revealed two cell types which can be distinguished according to the behaviour of their action potentials in sodium-free Ringer. Sodium-sensitive cells are unable to support action potentials for more than 8-10 min in the absence of sodium. Sodium slopes of between 29 and 37 mV per decade change in [Na+0] have been found for these cells. Tetrodotoxin (5 x 10-5 M) usually blocks action potentials in these neurones. Calcium-free inger produces a marked reduction in the overshoot potential and calcium slopes of about 18 mV per decade change in [Ca2+o] are found. Manganous chloride only partially reduces the action potential overshoot in these cells at concentrations of 10 mM/l. 3. Sodium-insensitive neurones maintain action potentials in the absence of external sodium. Stimulation only slightly reduces the amplitude of the action potential under these conditions and such cells are readily accessible to potassium ions in the bathing medium. A calcium-slope of 29 mV per decade change in [Ca2+o] has been observed in these cells in the absence of external sodium. 4. It is concluded that both sodium and calcium ions can be involved in the generation of the action potential in neurones of Limnaea stagnate, their relative contribution varying in different cells.

scholarly journals Pinocytosis in the developing egg of Limnaea stagnalis L

1960 ◽  
Vol 21 (3) ◽  
pp. 619-622 ◽  
Author(s):  
P.F. Elbers ◽  
J.G. Bluemink
Keyword(s):  
Limnaea Stagnalis

The Formation of the Second Maturation Spindle in the Eggs of Limnaea, Limax, and Agriolimax

Development ◽  
1958 ◽  
Vol 6 (1) ◽  
pp. 28-51
Author(s):  
Chr. P. Raven ◽  
Frouke C. M. Escher ◽  
W. M. Herrebout ◽  
J. A. Leussink
Keyword(s):  
Polar Body ◽  
Egg Maturation ◽  
First Polar Body ◽  
Limnaea Stagnalis ◽  
Gradual Transformation ◽  
Sperm Aster

Egg maturation in Limnaea stagnalis has been described by Raven (1945, 1949). It exhibits some peculiarities, by which the Limnaea egg seemed to stand apart from all other animal eggs in which the maturation processes have been accurately studied so far. In the first place it appeared that the second maturation spindle arises by a direct and gradual transformation of the centrosphere at the inner end of the first maturation amphiaster, remaining in the egg after the extrusion of the first polar body. Secondly, the above-mentioned investigations revealed the still more astonishing fact that the inner aster of the second maturation spindle is none other than the sperm aster, which arises quite independently round about the time of the extrusion of the first polar body, grows considerably in size while the second maturation spindle is being formed, and then fuses secondarily with the latter's deep end.

scholarly journals Functional Implications of Neurotransmitter Expression during Axonal Regeneration: Serotonin, But Not Peptides, Auto-Regulate Axon Growth of an Identified Central Neuron

2001 ◽  
Vol 21 (15) ◽  
pp. 5597-5606 ◽  
Author(s):  
Cornelis E. Koert ◽  
Gaynor E. Spencer ◽  
Jan van Minnen ◽  
Ka Wan Li ◽  
Wijnand P. M. Geraerts ◽  
...  
Keyword(s):  
Axonal Regeneration ◽  
Axon Growth ◽  
Central Neuron ◽  
Functional Implications

On the Structure and Life-histories of British Fresh-water Larval Trematodes

Parasitology ◽  
1929 ◽  
Vol 21 (1-2) ◽  
pp. 189-219 ◽  
Author(s):  
W. F. Harper
Keyword(s):  
Fresh Water ◽  
Life Histories ◽  
The Other ◽  
Trematode Species ◽  
Intermediate Hosts ◽  
Double Infection ◽  
Activity Duration ◽  
Large Numbers ◽  
Limnaea Stagnalis ◽  
First Time

A large number of fresh-water Invertebrates has been examined and the parasites obtained from them include examples of the commoner groups to be met with in any area surveyed. Six larval Trematodes have been described in detail, and by means of direct animal experiment two of them have been definitely related to known adults. Of these two one is the larva of Notocotylus seineti Fuhr., and is doubtfully Cercaria monostomi v. Linst., while the other is the larva of Echinoparyphium recurvatum v. Linst., and is described here in detail for the first time. The four xiphidiocercariae described are new. Data relating to the activity, duration of free life, and process of encystment of cercariae within the bodies of secondary intermediate hosts is also given.Effect of the parasite on the host. The disruption of the tissues brought about by the presence of sporocysts or rediae in the liver of a mollusc injures the host, and in many cases brings about its death. The gonads also are often attacked and completely destroyed. This latter feature of parasitic castration has been observed by Giard (1888) among certain species of Limnaea, Planorbis and Paludina attacked by sporocysts. Brown (1926) states that the gonads are rarely infected. As regards the encysted stages of cercariae these appear to do very little harm to their hosts even when present in large numbers. These observations are in agreement with those of Lebour (1912) for the sporocyst, rediae, and encysted stages of marine Trematodes.Double infection. I have found no instance of a double infection among the species described. In the literature, several records show the parasitism of two or more species of cercariae, within one and the same host. The occurrence of two species is most commonly met with, and as a rule one is in predominance. Sewell (1922) states that double infection is not common in India. Faust (1917), on the other hand, has found as many as four trematode species within the same host individual (Planorbis trivolis). Hesse (1923) states that “every large Limnaea peregra examined was heavily infected with sporocysts of either of the two species, but it was rare to find both together.” Brown (1926) in the neighbourhood of Birmingham has found three examples of associated xiphidiocercariae and furcocercariae, one example of xiphidiocercariae and echinostome cercariae, and two examples of echinostome cercaria, all from Limnaea stagnalis L.

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