An Electrophysiological Study of the Sodium and Potassium Permeabilities of Insect Peripheral Nerves

1973 ◽  
Vol 59 (2) ◽  
pp. 447-461
Author(s):  
Y. PICHON ◽  
J. E. TREHERNE
Keyword(s):  
Time Course ◽  
Periplaneta Americana ◽  
Schistocerca Gregaria ◽  
Fat Body ◽  
Electrophysiological Study ◽  
External Potassium ◽  
Sucrose Gap ◽  
Lag Period ◽  
Sodium And Potassium

1. Experiments carried out in situ, using suction electrodes, and in vitro, using the ‘sucrose-gap’, have demonstrated a restricted access of sodium and potassium ions to the axon surfaces in crural nerves of the cockroach Periplaneta americana and the locust Schistocerca gregaria. 2. Elevation of the external potassium concentration produced appreciable extra-neuronal potential changes in intact crural nerves of the locust. 3. In the locust the presence of the over lying fat body sheath was found to alter the time course of potassium-induced d.c. potential changes. 4. In particular, an initial lag period in the d.c. response is described and tentatively interpreted in terms of a cation reservoir effect.

INHIBITORS OF CARBONIC ANHYDRASE IN THE AMERICAN COCKROACH, PERIPLANETA AMERICANA (L.)

1956 ◽  
Vol 34 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Ann D. Anderson ◽  
Ralph B. March
Keyword(s):  
Carbonic Anhydrase ◽  
Periplaneta Americana ◽  
Fat Body ◽  
Aqueous Media ◽  
Carbonic Anhydrase Activity ◽  
American Cockroach ◽  
Tissue Homogenates ◽  
Organic Insecticides ◽  
Cell Fragments

Carbonic anhydrase activity has been demonstrated in vitro in preparations of the head, fat body, and gut of the American cockroach, Periplaneta americana (L.), and in the adult housefly, Musca domestica L. The insect factor, which is soluble in aqueous media and can be separated from the particulate cell fragments of insect tissue homogenates is heat labile and sensitive to cyanide inactivation. It is strongly inhibited by sulphanilamide, p-aminoethylphenyl-sulphonamide, and p-chlorphenylsulphonamide. No inhibition has been found with N-substituted sulphonamides or with any of the organic insecticides examined, including DDT, lindane, dieldrin, nicotine, rotenone, pyrethrins, and para-oxon. Sensitivity of carbonic anhydrase to sulphonamides having an intact—SO2NH2 group is also characteristic of mammalian preparations. The data indicate that inhibition of insect carbonic anhydrase cannot be an important factor in the mode of action of DDT or other organic insecticides.

Corpus cardiacum stimulated trehalose efflux from cockroach (Periplaneta americana) fat body: control by calcium

1985 ◽  
Vol 63 (1) ◽  
pp. 63-66 ◽  
Author(s):  
J. E. Steele ◽  
T. Paul
Keyword(s):  
Cyclic Amp ◽  
Periplaneta Americana ◽  
Saline Solution ◽  
Fat Body ◽  
Surrounding Medium ◽  
Physiological Saline ◽  
Corpus Cardiacum ◽  
Physiological Saline Solution ◽  
Stimulation Of

Cockroach fat body incubated in a simple physiological saline solution releases trehalose to the surrounding medium. The output of trehalose occurs in the absence of ambient Ca2+ and decreases slowly with time. In two separate experiments, 0.1 mM CaCl2 added to the saline increased the output of trehalose on average by 70% but higher concentrations of Ca2+ did not further increase the efflux of trehalose. Stimulation of trehalose efflux by corpus cardiacum extract is absolutely dependent on extracellular Ca2+, no increase occurring beyond the basal level in the absence of the ion. The activity of corpus cardiacum extract increases as the concentration of CaCl2 is increased to 0.5 mM. This concentration of Ca2+ in the saline permits the extract to increase trehalose efflux by as much as 60% above the basal level. Corpus cardiacum extract, as well as the hypertrehalocaemic agents cyclic AMP and theophylline, increase significantly the influx of Ca2+ into fat body in vitro. The basal efflux of trehalose from fat body and that stimulated by corpus cardiacum extract is not dependent on extracellular Mg2+.

Effect of Extracellular Potassium on the Transport of Sodium and Potassium in Rat Thymocytes

1981 ◽  
Vol 61 (3) ◽  
pp. 307-312 ◽  
Author(s):  
R. B. Jones ◽  
J. Patrick ◽  
P. J. Hilton
Keyword(s):  
Potassium Concentration ◽  
Extracellular Potassium ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Extracellular Potassium Concentration ◽  
External Potassium ◽  
Potassium Influx ◽  
Sodium And Potassium

1. The effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes has been studied in vitro. 2. A significant increase in the rate constant for total and ouabain-sensitive sodium efflux was demonstrated at an extracellular potassium concentration of 1 mmol/l as compared with that at either 0 or 2 mmol/l. 3. At potassium concentrations below 3 mmol/l ouabain-sensitive sodium influx was observed suggesting sodium-sodium exchange catalysed by the sodium pump. 4. Both total and ouabain-insensitive potassium efflux rose with external potassium. A small ouabain-sensitive potassium efflux was observed at all levels of external potassium studied. 5. Total and ouabain-insensitive potassium influx increased with external potassium, but did not appear to saturate. Ouabain-sensitive potassium influx reached a maximum at an external potassium concentration of 2 mmol/l then decreased with increasing external potassium.

Frusemide-Sensitive Sodium and Potassium Transport by Human Leucocytes

1985 ◽  
Vol 68 (1) ◽  
pp. 89-91 ◽  
Author(s):  
Valerie E. Johnson ◽  
P. J. Hilton
Keyword(s):  
Potassium Transport ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Sodium Potassium ◽  
External Potassium ◽  
Normal Human ◽  
Potassium Influx ◽  
Net Flux ◽  
Sodium And Potassium

1. Frusemide-sensitive sodium and potassium transport by normal human leucocytes has been studied in vitro by both isotopic and net flux techniques. 2. In physiological media the leucocyte exhibits a frusemide-sensitive influx of sodium and potassium of equal magnitude compatible with a 1:1 co-transport system. 3. Cells exposed to zero external sodium and potassium (osmolality maintained with choline) demonstrated a frusemide-sensitive sodium and potassium efflux. 4. Frusemide-sensitive potassium influx was dependent on the presence of external sodium but frusemide-sensitive sodium influx persisted unchanged in the absence of external potassium. 5. Frusemide-sensitive potassium influx was dependent on external chloride but frusemide-sensitive sodium influx was chloride-independent. 6. These last two observations make it likely that the frusemide-sensitive pathway is capable of operating in modes other than sodium-potassium co-transport.

An electrophysiological analysis of extra-axonal sodium and potassium concentrations in the central nervous system of the cockroach (Periplaneta americana L.)

1975 ◽  
Vol 63 (3) ◽  
pp. 801-811
Author(s):  
M. V. Thomas ◽  
J. E. Treherne
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Action Potentials ◽  
Periplaneta Americana ◽  
Sodium Concentration ◽  
Blood Potassium ◽  
The Central Nervous System ◽  
Sucrose Gap ◽  
Sodium And Potassium

Simultaneous intracellular and sucrose-gap recordings showed, in contrast to previous findings, that the electrical parameters of giant axons were similar to intact and desheathed connectives bathed with the ‘extracellular Ringer’ of Yamasaki & Narahashi. This implies that the extra-axonal sodium concentration, in situ, is likely to be lower than had been previously supposed. Axonal responses showed that, despite the high blood concentration of 24–2 mM-K+ measured by flame photometry, the effective concentration in the blood was 10–15 mM-K+ which corresponds to the measurements made with potassium-selective electrodes. The activity of the blood potassium ions caused a marked reduction in the amplitude of the action potentials following surgical desheathing or disruption of the blood-brain barrier with hypertonic urea. It is suggested that a regulatory mechanism exists in the central nervous system which counteracts the effects of the high blood potassium level.

Naturally occurring agglutinins against trypanosomatid flagellates in the haemolymph of insects

Parasitology ◽  
1984 ◽  
Vol 89 (3) ◽  
pp. 435-451 ◽  
Author(s):  
G. A. Ingram ◽  
Janet East ◽  
D. H. Molyneux
Keyword(s):  
Periplaneta Americana ◽  
Schistocerca Gregaria ◽  
Normal Values ◽  
Model Systems ◽  
Induced Response ◽  
Induced Responses ◽  
Naturally Occurring ◽  
Physico Chemical ◽  
Prior Infection

SUMMARYIn vitrostudies of the behaviour of the trypanosomatid flagellatesTrypanosoma bruceiandLeishmania hertigiin the presence of cell-free haemolymph of locusts,Schistocerca gregariaand cockroaches,Periplaneta americanarevealed the presence of parasite agglutinins. The range of normal values of agglutination titres was 2−4to 2−13. Physico-chemical treatment of haemolymph indicated that these agglutinins are protein or glycoprotein in nature and are only partially affected by heat treatment below 65°C, at which temperature incubation of haemolymph for 30 min abrogated all agglutination. Agglutination was not dependent on the presence of Ca2+or Mg2+. Prior infection of locusts and cockroaches withT. bruceiandL. hertigisignificantly increased agglutinin titres between Days 4 and 6 in cockroaches (P< 0·05) and from Days 2 to 4 whenL. hertigiwas inoculated into locusts. The induced differences in titres observed in locusts infected withT. bruceiwere not significant. Lysozyme levels were significantly increased after inoculation ofT. bruceiinto cockroaches compared with placebo-inoculated and uninoculated controls.L. hertigiinoculation produced significant increases in lysozyme levels compared with controls between Days 1 and 7 in locusts and 3 to 6 in cockroaches. These studies indicate that, at least in easily manipulated model systems, induced responses to intrahaemocoelic inoculation to trypanosomes andLeishmaniacan occur. As far as we are aware this is the first report of an induced response of an insect to such important parasites. The possibility that induced responses in natural vectors to these parasites occurs requires investigation.

Effect of substratum wettability and charge on adhesion in vitro and encapsulation in vivo by insect haemocytes

1983 ◽  
Vol 63 (1) ◽  
pp. 181-190 ◽  
Author(s):  
A.M. Lackie
Keyword(s):  
Periplaneta Americana ◽  
Schistocerca Gregaria ◽  
Body Cavity ◽  
Similar Proportion ◽  
Cell Behaviour ◽  
Polystyrene Beads ◽  
Abiotic Surfaces ◽  
Insect Haemocytes

The circulating leucocytes of insects, the haemocytes, adhere to and encapsulate foreign material that enters the insect's body cavity. The thickness of the capsule depends not only on the insect species but also on the nature of the object concerned, a fact that is of great importance to invading parasites and pathogens. In this paper, some of the factors that may stimulate haemocyte adhesion and subsequent encapsulation of the object have been investigated using abiotic materials with surfaces of different charge and wettability. The negativity and wettability of surfaces of polystyrene beads and plates can be increased by pretreatment with acid, and adhesion of haemocytes to these modified surfaces has been examined in vivo and in vitro. A similar proportion of haemocytes of the locust Schistocerca gregaria adhere to the plates in vitro, irrespective of the changes in charge and wettability, but the adhesion of haemocytes of the cockroach Periplaneta americana is proportional to the increases in both parameters. These differences in cell behaviour are reflected in vivo: cockroach haemocytes form thicker capsules around more hydrophilic and more negatively charged polystyrene beads, while locust cells encapsulate both types of surface to the same, minimal, degree. Positively and negatively charged Sepharose beads are encapsulated more thickly than are neutral beads in cockroaches; negatively charged Sepharose beads are not encapsulated at all in locusts. There are thus obvious differences between the two species in the ways in which their haemocytes respond to these modified abiotic surfaces. It is suggested that capsule thickness in vivo depends on the initial cell-substratum contact; different surfaces stimulate the cell to different extents, which in turn causes variations in the recruitment of other cells to the capsule.

Surface charge of insect haemocytes, examined using cell electrophoresis and cationized ferritin-binding

1985 ◽  
Vol 75 (1) ◽  
pp. 207-214
Author(s):  
G. Takle ◽  
A.M. Lackie
Keyword(s):  
Surface Charge ◽  
Periplaneta Americana ◽  
Schistocerca Gregaria ◽  
Cationized Ferritin ◽  
Cell Electrophoresis ◽  
Insect Haemocytes ◽  
Negative Surface ◽  
Negative Surface Charge

Differences in the negative surface charge of haemocytes from Periplaneta americana and Schistocerca gregaria have been revealed using cell electrophoresis and cationized ferritin-binding. Although haemocyte populations from both insect species exhibit ranges of negative surface charge, both techniques show that Schistocerca haemocytes are significantly more negative than Periplaneta haemocytes. The results may help to explain why Schistocerca haemocytes adhere poorly to negative substrata, both in vitro and in vivo, and suggest that an electrostatic mechanism may be involved, at least in part, in adhesion of insect haemocytes to substrata.

Origin of trehalose in stress-induced hyperglycaemia in the american cockroach, Periplaneta americana

1974 ◽  
Vol 52 (8) ◽  
pp. 1005-1010 ◽  
Author(s):  
J. R. Matthews ◽  
R. G. H. Downer
Keyword(s):  
Adult Male ◽  
Time Course ◽  
Periplaneta Americana ◽  
Fat Body ◽  
American Cockroach

The time course of stress-induced hyperglycaemia was determined in adult male Periplaneta americana, and a rapid elevation of haemolymph trehalose concentration is reported. Intracellular fat body trehalose concentrations were measured in the resting insect and found to be equivalent to haemolymph trehalose levels. In active insects, the apparent intracellular fat body trehalose concentration is greater than that of the haemolymph, and is dependent upon the time taken for dissection. The rate of production of trehalose in isolated fat body is equivalent to the rate of appearance of haemolymph trehalose in hyperglycaemia.

Sign in / Sign up

Export Citation Format

Share Document