scholarly journals Physiological Effects of a Hypotonic Environment

1940 ◽  
Vol 17 (3) ◽  
pp. 337-352
Author(s):  
G. P. WELLS ◽  
ISABEL C. LEDINGHAM
Keyword(s):  
Body Wall ◽  
Sea Water ◽  
Rapid Change ◽  
Natural Conditions ◽  
Bathing Medium ◽  
Nereis Diversicolor ◽  
Arenicola Marina ◽  
Lower Salinity ◽  
Hypotonic Fluid ◽  
Two Phases

1. The reactions of isolated rhythmic preparations from Arenicola marina, Nereis diversicolor and Perinereis cultrifera to hypotonic saliness are described. 2. The preparations used were (1) the "isolated extrovert" of all three species, (2) ventral longitudinal body-wall strips of the two last named. All these preparations are essentially alike in their reactions to dilution of the bathing medium. 3. On abruptly changing from sea water to a hypotonic fluid, responses of the following general type are seen: first, brief excitement; then a phase of more or less complete inhibition; finally, provide the hypotonic fluid is not below a lower salinity limit characteristic of the preparation, gradual return of activity as the preparation accommodates itself to the new medium. The first two phases are shock effects of sudden dilution. The inhibition phase may last for many hours. 4. Preparations were exposed to salinities which fell gradually at various speeds. From the results of these experiments it is inferred that shock effects of rapid change are unlikely to be evoked under natural conditions, at least in Arenicola and Nereis. 5. The lower salinity limits for spontaneous activity in the tissues of the various species are: Perinereis cultrifera, 20-25% sea water; Arenicola marina, 15-20%; Nereis diversicolor, 5-10%. The results are discussed with reference to the ability to live in brackish water. 6. On suddenly returning from a hypotonic fluid to normal the responses vary. There may be relatively slight excitation (Arenicola marina extrovert) or a cycle of excitation--inhibition--accommodation like that evoked by a sudden downward change (Nereis diversicolor body wall).

Excretion of thiosulphate, the main detoxification product of sulphide, by the lugworm arenicola marina L

1999 ◽  
Vol 202 (7) ◽  
pp. 855-866 ◽  
Author(s):  
K. Hauschild ◽  
W.M. Weber ◽  
W. Clauss ◽  
M.K. Grieshaber
Keyword(s):  
Body Wall ◽  
Sea Water ◽  
The Body ◽  
Cell Junctions ◽  
Metabolic Inhibitors ◽  
Coelomic Fluid ◽  
Arenicola Marina ◽  
Double Exponential ◽  
Electrophysiological Measurements ◽  
Double Exponential Function

Thiosulphate, the main sulphide detoxification product, is accumulated in the body fluids of the lugworm Arenicola marina. The aim of this study was to elucidate the fate of thiosulphate. Electrophysiological measurements revealed that the transepithelial resistance of body wall sections was 76+/−34 capomega cm2 (mean +/− s.d., N=14), indicating that the body wall of the lugworm is a leaky tissue in which mainly paracellular transport along cell junctions takes place. The body wall was equally permeable from both sides to thiosulphate, the permeability coefficient of which was 1. 31×10(−)3+/−0.37×10(−)3 cm h-1 (mean +/− s.d., N=30). No evidence was found for a significant contribution of the gills or the nephridia to thiosulphate permeation. Thiosulphate flux followed the concentration gradient, showing a linear correlation (r=0.997) between permeated and supplied (10–100 mmol l-1) thiosulphate. The permeability of thiosulphate was not sensitive to the presence of various metabolic inhibitors, implicating a permeation process independent of membrane proteins and showing that the lugworm does not need to use energy to dispose of the sulphide detoxification product. The present data suggest a passive permeation of thiosulphate across the body wall of A. marina. In live lugworms, thiosulphate levels in the coelomic fluid and body wall tissue decreased slowly and at similar rates during recovery from sulphide exposure. The decline in thiosulphate levels followed a decreasing double-exponential function. Thiosulphate was not further oxidized to sulphite or sulphate but was excreted into the sea water.

scholarly journals Spontaneous activity patterns in animal behaviour: the irrigation of the burrow in the polychaetes Chaetopterus variopedatus Renier and Nereis diversicolor O. F. Müller

1951 ◽  
Vol 29 (3) ◽  
pp. 661-680 ◽  
Author(s):  
G. P. Wells ◽  
R. Phillips Dales
Keyword(s):  
Spontaneous Activity ◽  
Small Volume ◽  
Sea Water ◽  
Activity Patterns ◽  
Animal Behaviour ◽  
The Other ◽  
Nereis Diversicolor ◽  
Arenicola Marina ◽  
Water Currents ◽  
Chaetopterus Variopedatus

Simple methods for recording the water currents, which many polychaetes drive through their tubes, are described. The circulation may be either open (the worm having access to large amounts of well-aerated sea water) or closed (in which case the worm can circulate a small volume only, and there is no oxygenacion or removal of excretory products).When on open circulation, both Chaetopterus variopedatus and Nereis diversicolor often trace quite regularly cyclical patterns for hours at a stretch. Each species has several possible patterns, and may change from one to another without evident external cause. The tracings of each species differ from those of the other, and also from those of Arenicola marina, which were described elsewhere.

scholarly journals Studies on the Physiology of Arenicola Marina L.

1942 ◽  
Vol 19 (2) ◽  
pp. 176-185
Author(s):  
G. P. WELLS ◽  
I. C. LEDINGHAM
Keyword(s):  
Steady State ◽  
Sea Water ◽  
Potassium Concentration ◽  
Short Exposure ◽  
Simultaneous Increase ◽  
Distinctive Pattern ◽  
Bathing Medium ◽  
Arenicola Marina ◽  
Pattern Characteristic ◽  
Simultaneous Decrease

1. The effects on the isolated extrovert of Arenicola marina L. of varying the potassium concentration of the bathing medium are described. Data are also presented on K : Mg antagonism. Potassium and magnesium concentrations are given as multiples of their concentrations in artificial sea water, which was taken as the ‘normal’ starting fluid. 2. The extrovert normally shows a distinctive pattern of alternating periods of activity and rest, superposed on the more general properties of rhythm and tone. This pattern is very sensitive to changes in potassium concentration. Moderate changes produce modifications of the pattern. Severe changes abolish the pattern and produce effects on rhythm and tone resembling those shown by most rhythmic muscles under like conditions. 3. Moderate K excess (K 1.5-3.5) excites tone and rhythm. Accommodation occurs during long exposure. The effects resemble those of Mg deficit, and can be completely abolished by increasing the Mg concentration. 4. An increase of lever weight has effects on the rhythm resembling those of a moderate K excess or a moderate Mg deficit, but in this case there is no accommodation. It is suggested that the extrovert contains a steady state system such as k0kS↔A→ Bwhere S is a source and the performance of the extrovert depends, through B, on the rate of the process A→B. If change in the K : Mg balance acts on k, its result will be following automatically by accommodation. Change in tension can produce the same end-result, without accommodation, by acting on B. 5. Severe K excess (K 5-10) causes contracture and inhibition of the rhythm. The contracture is partly antagonized by simultaneous increase in Mg, but the inhibition is not antagonized. 6. Moderate K deficit (K 0.75-0.33) causes initial excitement, then a characteristically modified pattern, with widely spaced activity outbursts, and an occasional abnormally long outburst. These effects are not antagonized by simultaneous decrease in Mg. As, however, they are not seen in preparations exposed to sea water diluted to four times its volume, they are due to disturbance of a balance between K and some other constituent of the medium. 7. Severe K deficit (K 0.05 or 0.00) causes partial contracture with chaotic activity, which lasts for many hours. Neither effect can be antagonized by simultaneous decrease in Mg. With borderline deficits (K 0.25 or 0.20) the preparation reacts at first as if to severe deficit, then accommodates itself and gives the pattern characteristic of moderate deficit. 8. The potassium paradox occurs on returning to artificial sea water after severe deficit. With borderline deficits (K 0.25 or 0.20) it is seen after short exposure, but not after long.

The Integration of Activity Cycles in the Behaviour of Arenicola Marina L

1951 ◽  
Vol 28 (1) ◽  
pp. 41-50
Author(s):  
G. P. WELLS ◽  
ELINOR B. ALBRECHT
Keyword(s):  
Body Wall ◽  
Sea Water ◽  
Rhythmic Activity ◽  
The Body ◽  
Neuromuscular System ◽  
Arenicola Marina ◽  
Cyclic Behaviour ◽  
Feeding Cycle ◽  
Activity Cycles ◽  
Set Up

1. Lugworms were dissected in such a way that the movements of the following parts could be simultaneously recorded: extrovert, body wall from the anterior three segments, body wall from the branchiate segments, tail. The preparations were set up in sea water and tracings were taken for many hours in each case. The preparations typically settled down to give cyclic behaviour patterns, remarkably similar to those which intact worms exhibit under favourable conditions, and in which two components were conspicuous. 2. The first, and most invariable, component is the feeding cycle (f cycle), of period 6-7 min. This rhythm originates in the oesophagus, and is transmitted to the muscles of the proboscis (where it causes outbursts of vigorous contraction) and body wall (where it causes correlated contractions in the first three segments, but periodic inhibition in the branchiate segments). 3. The second component was seen in two-thirds of the experiments. It consists of bursts of vigorous rhythmic activity in the body wall and tail, and can appear after their connexion with the extrovert has been severed. Under exceptional circumstances (exhaustion of the f cycle) it may spread to the extrovert trace. Its period is generally 20-60 min. It is apparently identical with the irrigation-defaecation cycle (i-d cycle) of intact worms. 4. Neither pacemaker directly affects the rhythm of the other. The integration of the activities which they determine probably depends on variation in the extent to which their influences spread through the neuromuscular system. They appear to compete for territory. If they happen to discharge outbursts simultaneously, the i-d pacemaker dominates over most of the body wall, and the f pacemaker over the proboscis and mouth region.

The Regulation of Calcium and Magnesium in the Brackish Water Polychaete Nereis Diversicolor O.F.M

1970 ◽  
Vol 53 (2) ◽  
pp. 425-443
Author(s):  
C. R. FLETCHER
Keyword(s):  
Brackish Water ◽  
Calcium Concentration ◽  
Sea Water ◽  
Calcium Influx ◽  
Coelomic Fluid ◽  
Nereis Diversicolor ◽  
Active Uptake ◽  
Calcium And Magnesium ◽  
Electrochemical Potentials

1. Nereis diversicolor tolerates changes in the concentration of calcium and magnesium in its coelomic fluid proportional to the concentrations in the medium between chlorosities of 100-1000 mM/kg of water. 2. In lower salinities both ions are maintained relatively constant providing that the ratios of these ions to chloride in the medium are similar to the ratios in sea water. 3. The ratio of the concentration of calcium in the coelomic fluid to the concentration in the medium is a function of the salinity of the medium but not of the calcium concentration. 4. Both calcium and magnesium are at lower electrochemical potentials in the coelomic fluid than in the medium, indicating that it is not necessary to invoke active uptake. 5. The rate of calcium influx is substantial. 6. In salinities below to mM of chloride/kg of water the urine must contain less calcium than the coelomic fluid. 7. The significance of these results is discussed.

Long-term Adaptations of Sabella Giant Axons to Hyposmotic Stress

1978 ◽  
Vol 75 (1) ◽  
pp. 253-263
Author(s):  
J. E. TREHERNE ◽  
Y. PICHON
Keyword(s):  
Sea Water ◽  
Potassium Concentration ◽  
Resting Potential ◽  
Sodium Permeability ◽  
Bathing Medium ◽  
Appreciable Change ◽  
Axon Membrane ◽  
Giant Axons

Reprint requests should be addressed to Dr Treherne. Sabella is a euryhaline osmoconformer which is killed by direct transfer to 50% sea water, but can adapt to this salinity with progressive dilution of the sea water. The giant axons were adapted to progressive dilution of the bathing medium (both in vivo and in vitro) and were able to function at hyposmotic dilutions (down to 50%) sufficient to induce conduction block in unadapted axons. Hyposmotic adaptation of the giant axon involves a decrease in intracellular potassium concentration which tends to maintain a relatively constant resting potential during adaptation despite the reduction in external potassium concentration. There is no appreciable change in the intracellular sodium concentration, but the relative sodium permeability of the active membrane increases during hyposmotic adaptation. This increase partially compensates for the reduction in sodium gradient across the axon membrane, during dilution of the bathing media, by increasing the overshoot of the action potentials recorded in hyposmotically adapted axons.

Heat transfer between fish and ambient water

1976 ◽  
Vol 65 (1) ◽  
pp. 131-145 ◽  
Author(s):  
E. D. Stevens ◽  
A. M. Sutterlin
Keyword(s):  
Body Wall ◽  
Sea Water ◽  
The Body ◽  
Direct Transfer ◽  
Major Fraction ◽  
Metabolic Heat ◽  
Sea Raven ◽  
Before And After ◽  
Ventral Aorta ◽  
Hemitripterus Americanus

1. The ability of fish gills to transfer heat was measured by applying a heat pulse to blood in the ventral aorta and measuring it before and after passing through the gills of a teleost, Hemitripterus americanus. 2. 80–90% of heat contained in the blood is lost during passage through the gills. 3. The fraction of heat not lost during passage through the gills is due to direct transfer of heat between the afferent and efferent artery within the gill bar. 4. The major fraction of metabolic heat (70 - 90%) is lost through the body wall and fins of the sea raven in sea water at 5 degrees C; the remainder is lost through the gills.

Mn2+ Ions Pass Through Ca2+ Channels in Myoepithelial Cells

1979 ◽  
Vol 82 (1) ◽  
pp. 227-238
Author(s):  
M. ANDERSON
Keyword(s):  
Sea Water ◽  
Myoepithelial Cells ◽  
Fold Change ◽  
Applied Current ◽  
Bathing Medium ◽  
Current Pulses ◽  
Marine Polychaete ◽  
Intracellular Stimulation ◽  
Pass Through ◽  
Ca2 Channels

1. Intracellular recordings were made from the myoepithelial cells of the proventriculus of the marine polychaete worm Syllis spongiphila. Overshooting responses were elicited either by carbamylcholine added to the bathing medium or by directly applied intracellular current pulses. 2. In control artificial sea water (ASW) directly applied current pulses elicited regenerative responses of 68–119 mV in amplitude and 70–1800 ms in duration; these responses were associated with contractions of the myoepithelial cells. 3. Both pharmacologically and electrically elicited responses were reversibly abolished in Ca-free ASW and were unaffected by TTX or lowsodium solutions. Regenerative responses were elicited by direct intracellular stimulation in calcium-free ASW containing 1 mM-B2+ or 10 mM-Sr2+. Directly elicited responses were blocked reversibly in ASW containing calcium and 15-20 mM-Co2+ or 2.5-10 mM-Ni2+; they were blocked irreversibly in ASW containing calcium and 10 mM-La3+ or 100 μM-Zn2+. 4. Regenerative responses were elicited in Ca-free solutions containing 10-50 mM-Mn2+; these responses were not associated with contractions, were consistently of longer duration than responses elicited in control ASW, and were blocked by 20 mM-Co2+ or 10 mM-La3+. The overshoots of Mn2+ responses elicited in both Na-free and Na-containing, Ca-free solutions increased as the external concentration of Mn2+ was increased, with a slope of about 27 mV per 10-fold change in concentration of Mn2+. In Cacontaining solutions the slope was reduced to about 15mV per 10-fold change. 5. The results indicate that the myoepithelial cells generate Ca-spikes and that Mn2+ ions, in addition to Sr2+ and Ba2+ ions, pass through the Ca2+ channels of the myoepithelial cell membranes. Although Mn^ can replace Ca2+ in generating spikes, it apparently cannot replace Ca2+ in initiating contraction, and it many compete with Ca2+ in activating repolarization of the cell.

The Mechanism of Proboscis Movement in Arenicola

1954 ◽  
Vol s3-95 (30) ◽  
pp. 251-270
Author(s):  
G. P. WELLS
Keyword(s):  
Body Fluid ◽  
Body Wall ◽  
The Body ◽  
Stage I ◽  
Stage Iii ◽  
Forward Movement ◽  
Arenicola Marina ◽  
Buccal Mass ◽  
The Difference ◽  
Longitudinal Muscles

The mechanism of proboscis movement is analysed in detail in Arenicola marina L. and A. ecaudata Johnston, and discussed in relation to the properties of the hydrostatic skeleton. Proboscis activity is based on the following cycle of movements in both species. Stage I. The circular muscles of the body-wall and buccal mass contract; the head narrows and lengthens. Stage IIa. The circular muscles of the mouth and buccal mass relax; the gular membrane (or ‘first diaphragm’ of previous authors) contracts; the mouth opens and the buccal mass emerges. Stage IIb. The longitudinal muscles of the buccal mass and body-wall contract; the head shortens and widens and the pharynx emerges. Stage III. As Stage I. The two species differ anatomically and in their hydrostatic relationships. In ecaudata, the forward movement of body-fluid which extrudes and distends the proboscis is largely due to the contraction of the gular membrane and septal pouches. In marina, the essential mechanism is the relaxation of the oral region which allows the general coelomic pressure to extrude the proboscis. The gular membrane of marina contracts as that of ecaudata does, but its anatomy is different and it appears to be a degenerating structure as far as proboscis extrusion is concerned. Withdrawal of the proboscis may occur while the head is still shortening and widening in Stage IIb, or while it is lengthening and narrowing in Stage III. The proboscis is used both in feeding and in burrowing; in the latter case nothing enters through the mouth; the difference is largely caused by variation in the timing of withdrawal relative to the 3-stage cycle.

Defense Mechanisms in Notaspid Snails: Acid Humor and Evasiveness

1991 ◽  
Vol 156 (1) ◽  
pp. 335-347 ◽  
Author(s):  
RHANOR GILLETTE ◽  
MAYUKO SAEKI ◽  
RONG-CHI HUANG
Keyword(s):  
Acid Secretion ◽  
Avoidance Behavior ◽  
Defense Mechanisms ◽  
Body Wall ◽  
Potential Role ◽  
Sea Water ◽  
Neural Pathways ◽  
Pleurobranchaea Californica ◽  
Local Contraction ◽  
And Behavior

Notaspid snails are known for their defensive skin secretion of sulfuric acid (pH 1–2) in response to noxious stimuli. We observed acid secretion and behavior in five notaspid species, and studied them in detail in Pleurobranchaea californica. All species secreted acid in response to skin abrasion or compression. Moreover, all species showed stereotypic avoidance behavior to acidified sea water less acidic (pH 2–3) then their own secretions. In Pleurobranchaea, secretion could also be stimulated by dilute solutions of taurine, 10−5-10−2moll−1. Secretion began at the stimulated region and spread slowly for about a minute following stimulation. Local contraction and transient edema of the skin were associated with acid secretion. In de-ganglionated preparations secretion could be caused by orthodromic stimulation of body wall nerves, by mechanical stimulation or by taurine. These data suggest that acid secretion is a positive feedback process modulated by inhibitory paths and coordinated by both central and peripheral nervous systems. A picture emerges of a defensive secretory response that provides an additional noxious stimulus initiating or potentiating avoidance behavior. The data also suggest a potential role for taurine release from injured tissue and the existence of specific nociceptive neural pathways regulating complex behavior. In addition to deterring extraspecific predation, acid secretion could regulate interactions between animals of the same species.

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