Induction of Sulphate Transport and Hormonal Control of Fluid Secretion by Malpighian Tubules of Larvae of the Mosquito Aedes Taeniorhynchus

1978 ◽  
Vol 72 (1) ◽  
pp. 181-202 ◽  
Author(s):  
S.H. P. MADDRELL ◽  
J. E. PHILLIPS
Keyword(s):  
Sea Water ◽  
Fluid Secretion ◽  
Hormonal Control ◽  
Malpighian Tubules ◽  
High Rate ◽  
Sulphate Content ◽  
Thoracic Ganglia ◽  
Sulphate Transport ◽  
Aedes Taeniorhynchus ◽  
The Brain

1. 4th stage larvae of A. taeniorhynchus reared in sulphate-enriched sea water drink the medium at the same rate that they do when reared in sulphate-free sea water. They absorb into the haemolymph most of the water and nearly all of the sulphate from the ingested fluid. 2. Larvae are able to keep the concentration of sulphate in the haemolymph at levels well below that of the medium, even when this contains as much as 89 mM sulphate. 3. The Malpighian tubules of larvae reared in sulphate-containing waters soon develop an ability to transport sulphate. The rate of sulphate transport induced varies directly with the sulphate content of the water in which they are reared. This ability is not retained into the adult stage. 4. The rate of fluid secretion by isolated Malpighian tubules is increased by up to 20 times when they are exposed to saline containing 1.5 mM cyclic AMP or concentrations of 5-hydroxytryptamine higher than 10−6 5. Tubules isolated from unfed insects into stimulant-free saline secrete fluid only slowly, but similarly treated tubules from feeding insects initially secrete fluid very much faster. 6. Extracts of the brain and of the thoracic ganglia stimulate Malpighian tubules to secrete fluid at a high rate. The brain is about four times as rich a source of stimulant as is the chain of thoracic ganglia. Treatment of the surface of the structures in the head with K-rich saline leads to the release of a factor which stimulates fluid secretion by the Malpighian tubules. 7. The results suggest that the Malpighian tubules in larvae of A. taeniorhynchus are under the control of a diuretic hormone which is elaborated in the brain and possibly also in the thoracic ganglia and which reaches high levels in the circulating haemolymph of feeding animals. 8. The rate of sulphate transport by isolated Malpighian tubules is strongly affected by the rate of fluid secretion. This behaviour is compatible with a passive leak of transported sulphate from the lumen back into the haemolymph through the permeable wall of the tubule.

THE EFFECTS OF MANDUCA SEXTA DIURETIC HORMONE ON FLUID TRANSPORT BY THE MALPIGHIAN TUBULES AND CRYPTONEPHRIC COMPLEX OF MANDUCA SEXTA

1993 ◽  
Vol 178 (1) ◽  
pp. 231-243 ◽  
Author(s):  
N. Audsley ◽  
G. M. Coast ◽  
D. A. Schooley
Keyword(s):  
Cyclic Amp ◽  
Manduca Sexta ◽  
Fluid Transport ◽  
Basal Membrane ◽  
Fluid Secretion ◽  
Hormonal Control ◽  
Malpighian Tubules ◽  
Proximal Tubules ◽  
Fluid Absorption ◽  
Diuretic Hormone

1. Manduca sexta diuretic hormone (Mas-DH) stimulates fluid secretion by adult Malpighian tubules of M. sexta, demonstrating its site of diuretic action in M. sexta for the first time. It was not possible to develop a suitable bioassay to measure fluid secretion in larval proximal tubules. 2. Mas-DH has an antidiuretic action on the cryptonephric complex of larval M. sexta because it increases fluid absorption from the rectum. It appears that in this complex Mas-DH is acting on a Na+/K+/2Cl- co-transporter, presumably on the basal membrane of the cryptonephric Malpighian tubules, because Mas-DH-stimulated fluid absorption by the cryptonephric complex is inhibited by bumetanide or the removal of Cl-, Na+ or K+ from the haemolymph side of the tissue. This is the first demonstration of hormonal control of fluid absorption by the cryptonephric complex. 3. Concomitant with the stimulation of fluid transport, Mas-DH increases the amount of cyclic AMP secreted by adult Malpighian tubules and the cryptonephric complex. In addition, Mas-DH promotes cyclic AMP production by the larval proximal tubules.

The effect of external salinity on drinking rate and rectal secretion in the larvae of the saline-water mosquito Aedes taeniorhynchus

1977 ◽  
Vol 66 (1) ◽  
pp. 97-110
Author(s):  
T. J. Bradley ◽  
J. E. Phillips
Keyword(s):  
Sea Water ◽  
External Medium ◽  
Narrow Range ◽  
Saline Water ◽  
Fluid Secretion ◽  
Osmotic Concentration ◽  
Drinking Rate ◽  
Aedes Taeniorhynchus ◽  
External Salinity ◽  
Kinetics Of

1. The drinking rate of the saline-water mosquito larva Aedes taeniorhyncus (100 nl.mg-1.h-1) is unaffected by the salinity of the external medium, but is directly proportional to the surface area of the animal. 2. Haemolymph Na+, Mg2+, K+, Cl-, SO42- and osmotic concentrations were measured in larvae adapted to 10%, 100% and 200% seawater and were found to be regulated within a narrow range. 3. With the exception of potassium, ionic concentrations in rectal secretion were found to increase with increasing concentrations of the sea water in which larvae were reared. 4. The osmotic concentration of rectal secretion was unaffected by changes in haemolymph osmotic concentration but did rise when sodium or chloride concentrations of the haemolymph were increased. High levels of these ions also stimulated the rate of fluid secretion. 5. Transport of chloride and sodium by the rectum exhibits the kinetics of allosteric rather than classical enzymes.

Hormonal Control of the Malpighian Tubules of the Stick Insect, Carausius Morosus

1970 ◽  
Vol 52 (3) ◽  
pp. 653-665 ◽  
Author(s):  
DIANA E. M. PILCHER
Keyword(s):  
Stick Insect ◽  
Hormonal Control ◽  
The State ◽  
Malpighian Tubules ◽  
Suboesophageal Ganglion ◽  
Carausius Morosus ◽  
Corpora Cardiaca ◽  
Diuretic Hormone ◽  
The Brain

1. Urine secretion by isolated Malpighian tubules of Carausius is accelerated by a diuretic hormone which can be extracted from the brain, corpora cardiaca and suboesophageal ganglion. 2. The level of this hormone in the haemolymph varies according to the state of hydration of the insect. 3. The hormone is inactivated by the tubules, and a mechanism is proposed whereby the tubules might be controlled by the hormone in vivo.

scholarly journals The hormonal control of diuresis in the cabbage white butterfly Pieris brassicae

1976 ◽  
Vol 65 (3) ◽  
pp. 565-575
Author(s):  
S. W. Nicolson
Keyword(s):  
Pieris Brassicae ◽  
Corpus Allatum ◽  
Hormonal Control ◽  
Malpighian Tubules ◽  
Storage Site ◽  
Diuretic Activity ◽  
Corpus Cardiacum ◽  
Diuretic Hormone ◽  
Cabbage White Butterfly ◽  
The Brain

The diuresis which follows the pupal-adult ecdysis of Pieris brassicae is hormonally controlled. Use of the isolated Malpighian tubules as a bioassay shows the presence of substantial diuretic activity in homogenates of the brain and corpus cardiacum-corpus allatum complex. The hormone is probably produced in the brain and released from a storage site in the corpora cardiaca. The tubules of the butterfly are maximally responsive to the diuretic hormone at the time of eclosion.

The Retention of Amino Acids in the Haemolymph During Diuresis in Rhodnius

1980 ◽  
Vol 87 (1) ◽  
pp. 315-330
Author(s):  
S.H.P. MADDRELL ◽  
B.O.C. GARDINER
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
High Rate ◽  
Excretory System ◽  
Low Permeability ◽  
High Concentrations ◽  
Active Reabsorption ◽  
Very High

The haemolymph of Rhodnius is rich in amino acids. During the rapid diuresis after a blood meal, no more than trace amounts of amino acids are lost in the urine. There is no significant reabsorption of amino acids in the excretory system. That they escape elimination can instead be attributed to a combination of the low permeability of the Malpighian tubules to amino acids, the very high rate of fluid secretion by the tubules, and the dilution of the haemolymph by an expansion in its volume after feeding. Amino acid losses are low in spite of the fact that the tubules actively accumulate high concentrations of amino acids in their cells and passive losses from these stores augment to some extent the flux of amino acids into the lumen. At times other than during diuresis, fluid secretion by the Malpighian tubules is slow. Calculations show that haemolymph solutes can then passively reach the higher concentrations in the lumen that are required for the operation of the excretory system (which relies on unselective passive entry and active reabsorption of useful substances). An advantage of the extraordinarily high rate of fluid secretion during diuresis is that fluid excretion can be rapidly completed. There is then little time for significant amounts of haemolymph solute to be lost passively.

Fluid secretion and microvillar ultrastructure in mosquito malpighian tubules

1989 ◽  
Vol 257 (5) ◽  
pp. R1096-R1102
Author(s):  
T. J. Bradley ◽  
C. Snyder
Keyword(s):  
Fluid Transport ◽  
Fluid Secretion ◽  
Blood Feeding ◽  
Malpighian Tubules ◽  
Primary Cells ◽  
Ultrastructural Examination ◽  
Aedes Taeniorhynchus ◽  
Physiological Limit ◽  
Secretion Rates

The Malpighian tubules of fourth instar larvae, pupae, and female adults of the mosquito Aedes taeniorhynchus were examined with regard to in vitro fluid secretion rate and the ultrastructural features of the microvillar border of the primary cells. In vitro fluid secretion rates were determined after stimulation with 5-hydroxytryptamine. While larval tubules are capable of rapid fluid secretion, the tubules of pupae exhibit very low rates of secretion, indistinguishable from 0 nl/h. The capacity to secrete fluid returns after the pupal-adult molt and is further enhanced after blood feeding. Similar results were obtained in tubules stimulated in vitro with dibutyryl adenosine 3',5'-cyclic monophosphate. Ultrastructural examination of the microvillar border of the primary cells of the Malpighian tubules revealed that the period of reduced secretion capacity in the pupal tubules is correlated with a marked reduction in microvillar volume, microvillar surface area, and mitochondrial content in the microvillar border. The results suggest that microvilli of a certain size and containing extensions of mitochondria are required for rapid fluid transport. The absence of these conditions in pupal tubules cannot be overcome by in vitro stimulation with known secretagogues and therefore represents a physiological limit on transport performance in the pupal tubules of mosquitoes.

The secretion of hyperosmotic fluid by the rectum of a saline-water mosquito larva, Aedes taeniorhynchus

1975 ◽  
Vol 63 (2) ◽  
pp. 331-342 ◽  
Author(s):  
T. J. Bradley ◽  
J. E. Phillips
Keyword(s):  
Sea Water ◽  
Saline Water ◽  
Average Rate ◽  
Ionic Composition ◽  
Fluid Secretion ◽  
Osmotic Concentration ◽  
Aedes Taeniorhynchus ◽  
Osmotic Balance ◽  
Anal Papillae

1. Fourth-instar larvae of the mosquito A. taeniorhynchus (Wiedemann), when living in sea water, drink at a rate of 100 nl h(−1) larva(−1) and maintain ionic and osmotic levels in the haemolymph at about one-third those of the external medium. 2. Hyperosmotic urine is produced in the rectum by secretion of fluid having an osmotic concentration and ionic composition similar to that of sea water, with the exception that potassium levels are elevated 18-fold in the secretion. The average rate of fluid secretion observed was 19 nl h-1) larva(−1) with a maximum of 92 nl h(−1) larva(−1). 3. The concentration and volume of rectal secretion may be too low to account completely for osmotic balance. The possible role of anal papillae is discussed in this regard.

scholarly journals Fluid Secretion by the Malpighian Tubules of the Dragonfly Libellula Quadrimaculata

1985 ◽  
Vol 116 (1) ◽  
pp. 53-67 ◽  
Author(s):  
S. P. NICHOLLS
Keyword(s):  
Osmotic Pressure ◽  
External Medium ◽  
Salt Water ◽  
Tap Water ◽  
Fold Increase ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Secretion Rate ◽  
Thoracic Ganglia

Fluid secretion by the Malpighian tubules of Libellula quadrimaculata is unusual in that it is dependent on sodium and entirely independent of potassium in the external medium. It is suggested that this is due to the primitive, sodium-rich haemolymph of the Odonata. Similarities between these tubules and those of the millipede Glomeris marginata, which has a similar sodium-based haemolymph, support this view. Fluid secretion by the tubules is also dependent on the osmotic pressure of the external medium, declining considerably at higher osmotic pressures. However, there is no difference in the secretory rates of tubules isolated from larvae adapted to tap water, de-ionized water or salt water, even though there are large differences in the haemolymph osmotic pressure under these different conditions. This suggests some form of adaptation of the tubules in larvae from these different conditions. A factor which causes a five- to six-fold increase in the rate of secretion was present in the thoracic ganglia, and a slightly lower increase in secretion rate was recorded in larvae that had been feeding.

Dibutyryl cAMP activates bumetanide-sensitive electrolyte transport in Malpighian tubules

1991 ◽  
Vol 261 (3) ◽  
pp. C521-C529 ◽  
Author(s):  
J. L. Hegarty ◽  
B. Zhang ◽  
T. L. Pannabecker ◽  
D. H. Petzel ◽  
M. D. Baustian ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Fluid Secretion ◽  
Ringer Solution ◽  
Malpighian Tubules ◽  
Membrane Voltage ◽  
Dibutyryl Camp ◽  
K Secretion ◽  
Transepithelial Voltage

The effects of dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) and bumetanide (both 10(-4) M) on transepithelial Na+, K+, Cl-, and fluid secretion and on tubule electrophysiology were studied in isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti. Peritubular DBcAMP significantly increased Na+, Cl-, and fluid secretion but decreased K+ secretion. In DBcAMP-stimulated tubules, bumetanide caused Na+, Cl-, and fluid secretion to return to pre-cAMP control rates and K+ secretion to decrease further. Peritubular bumetanide significantly increased Na+ secretion and decreased K+ secretion so that Cl- and fluid secretion did not change. In bumetanide-treated tubules, the secretagogue effects of DBcAMP are blocked. In isolated Malpighian tubules perfused with symmetrical Ringer solution, DBcAMP significantly hyperpolarized the transepithelial voltage (VT) and depolarized the basolateral membrane voltage (Vbl) with no effect on apical membrane voltage (Va). Total transepithelial resistance (RT) and the fractional resistance of the basolateral membrane (fRbl) significantly decreased. Bumetanide also hyperpolarized VT and depolarized Vbl, however without significantly affecting RT and fRbl. Together these results suggest that, in addition to stimulating electroconductive transport, DBcAMP also activates a nonconductive bumetanide-sensitive transport system in Aedes Malpighian tubules.

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