Anti-diuretic activity of a CAPA neuropeptide can compromise Drosophila chill tolerance

2018 ◽  
Author(s):  
Heath A. MacMillan ◽  
Basma Nazal ◽  
Sahr Wali ◽  
Gil Y. Yerushalmi ◽  
Lidiya Misyura ◽  
...  
Keyword(s):  
Ion Transport ◽  
Cold Tolerance ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
Low Doses ◽  
Ion Balance ◽  
The Central Nervous System ◽  
Summary Statement ◽  
Cell Depolarization ◽  
High Doses

AbstractFor insects, chilling injuries that occur in the absence of freezing are often related to a systemic loss of ion and water balance that leads to extracellular hyperkalemia, cell depolarization, and the triggering of apoptotic signalling cascades. The ability of insect ionoregulatory organs (e.g. the Malpighian tubules) to maintain ion balance in the cold has been linked to improved chill tolerance, and many neuroendocrine factors are known to influence ion transport rates of these organs. Injection of micromolar doses of CAPA (an insect neuropeptide) have been previously demonstrated to improve Drosophila cold tolerance, but the mechanisms through which it impacts chill tolerance are unclear, and low doses of CAPA have been demonstrated to cause anti-diuresis in other insects, including dipterans. Here, we provide evidence that low (fM) and high (µM) doses of CAPA impair and improve chill tolerance, respectively, via two different effects on Malpighian tubule ion and water transport. While low doses of CAPA are anti-diuretic, reduce tubule K+ clearance rates and reduce chill tolerance, high doses facilitate K+ clearance from the haemolymph and increase chill tolerance. By quantifying CAPA peptide levels in the central nervous system, we estimated the maximum achievable hormonal titres of CAPA, and found evidence to suggest that CAPA may function as an anti-diuretic peptide in Drosophila. We provide the first evidence of a neuropeptide that can negatively affect cold tolerance in an insect, and the first evidence of CAPA as an anti-diuretic peptide in this ubiquitous insect model.Summary StatementMany insects ion balance in the cold. We show how one neuropeptide can slow ion transport and reduce the cold tolerance of a fly.

scholarly journals Active transport of brilliant blue FCF across the Drosophila midgut and Malpighian tubule epithelia

2019 ◽  
Author(s):  
Dawson B.H. Livingston ◽  
Hirva Patel ◽  
Andrew Donini ◽  
Heath A. MacMillan
Keyword(s):  
Traumatic Injury ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
Brilliant Blue ◽  
Barrier Dysfunction ◽  
Concentration Gradients ◽  
Barrier Disruption ◽  
Brilliant Blue Fcf ◽  
Summary Statement

AbstractUnder conditions of stress, many animals suffer from epithelial barrier disruption that can cause molecules to leak down their concentration gradients, potentially causing a loss of organismal homeostasis, further injury or death. Drosophila is a common insect model, used to study barrier disruption related to aging, traumatic injury, or environmental stress. Net leak of a non-toxic dye (Brilliant blue FCF) from the gut lumen to the hemolymph is often used to identify barrier failure under these conditions, but Drosophila are capable of actively transporting structurally-similar compounds. Here, we examined whether cold stress (like other stresses) causes Brilliant blue FCF (BB-FCF) to appear in the hemolymph of flies fed the dye, and if so whether Drosophila are capable of clearing this dye from their body following chilling. Using in situ midgut leak and transport assays as well as Ramsay assays of Malpighian tubule transport, we tested whether these ionoregulatory epithelia can actively transport BB-FCF. In doing so, we found that the Drosophila midgut and Malpighian tubules can mobilize BB-FCF via an active transcellular pathway, suggesting that elevated concentrations of the dye in the hemolymph may occur from increased paracellular permeability, reduced transcellular clearance, or both.Summary StatementDrosophila are able to actively secrete Brilliant blue FCF, a commonly used marker of barrier dysfunction

scholarly journals The septate junction protein Mesh is required for epithelial morphogenesis, ion transport, and paracellular permeability in the Drosophila Malpighian tubule

2020 ◽  
Vol 318 (3) ◽  
pp. C675-C694 ◽  
Author(s):  
Sima Jonusaite ◽  
Klaus W. Beyenbach ◽  
Heiko Meyer ◽  
Achim Paululat ◽  
Yasushi Izumi ◽  
...  
Keyword(s):  
Ion Transport ◽  
Malpighian Tubule ◽  
Paracellular Permeability ◽  
Malpighian Tubules ◽  
Septate Junction ◽  
Cell Junctions ◽  
Chloride Permeability ◽  
Transepithelial Potential ◽  
Junction Protein ◽  
Urine Production

Septate junctions (SJs) are occluding cell-cell junctions that have roles in paracellular permeability and barrier function in the epithelia of invertebrates. Arthropods have two types of SJs, pleated SJs and smooth SJs (sSJs). In Drosophila melanogaster, sSJs are found in the midgut and Malpighian tubules, but the functions of sSJs and their protein components in the tubule epithelium are unknown. Here we examined the role of the previously identified integral sSJ component, Mesh, in the Malpighian tubule. We genetically manipulated mesh specifically in the principal cells of the tubule at different life stages. Tubules of flies with developmental mesh knockdown revealed defects in epithelial architecture, sSJ molecular and structural organization, and lack of urine production in basal and kinin-stimulated conditions, resulting in edema and early adult lethality. Knockdown of mesh during adulthood did not disrupt tubule epithelial and sSJ integrity but decreased the transepithelial potential, diminished transepithelial fluid and ion transport, and decreased paracellular permeability to 4-kDa dextran. Drosophila kinin decreased transepithelial potential and increased chloride permeability, and it stimulated fluid secretion in both control and adult mesh knockdown tubules but had no effect on 4-kDa dextran flux. Together, these data indicate roles for Mesh in the developmental maturation of the Drosophila Malpighian tubule and in ion and macromolecular transport in the adult tubule.

Effects of chlordiazepoxide administration on biogenic amines in cat brain

1983 ◽  
Vol 61 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Luc Vachon ◽  
Andree G. Roberge
Keyword(s):  
Central Nervous System ◽  
Biogenic Amines ◽  
Low Doses ◽  
Brain Areas ◽  
Cat Brain ◽  
Hydroxyindoleacetic Acid ◽  
The Central Nervous System ◽  
High Doses ◽  
The Brain ◽  
Chlordiazepoxide Hydrochloride

Cats underwent treatment with chlordiazepoxide hydrochloride (0.4, 10.0, and 20.0 mg/kg per os), for 7 consecutive days, and were killed 18 h after the last administration. The endogenous levels of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), noradrenaline (NA), and dopamine (DA) were assayed in 12 brain areas. Few effects on 5-HT, 5-HIAA, and NA content and on the 5-HT:5-HIAA ratio were observed with a 0.4 mg/kg treatment. These changes were localized in the piriform lobe (amygdala), hippocampus, mesencephalon, and mesencephalon raphe nuclei. Moreover, the DA concentration was not affected. The changes produced by 10.0 and 20.0 mg/kg chlordiazepoxide treatments were extended to many more structures, including the limbic system, brainstem, diencephalon, and neostriatum with respect to 5-HT, 5-HIAA, and NA content and also to DA levels. The changes observed after the three doses generally included an increased 5-HT content, a decreased 5-HIAA level, a high 5-HT:5-HIAA ratio, and increased NA and DA concentrations. However, in some structures, a decreased NA content and an increased 5-HIAA level were found. The present results suggest that administration of chlordiazepoxide for 7 consecutive days in cats produces regional changes in the content of endogenous biogenic amines in the central nervous system (CNS) at low doses; much more extended effects are produced at high doses. These findings are in agreement with a reducing effect of benzodiazepines on the turnover and release of biogenic amines in the CNS, but also suggest that certain discrete areas are more involved in these changes, thus dissociating them from the rest of the brain.

Characteristics of emodin on modulating the contractility of jejunal smooth muscle

2012 ◽  
Vol 90 (4) ◽  
pp. 455-462 ◽  
Author(s):  
Dapeng Chen ◽  
Yongjian Xiong ◽  
Li Wang ◽  
Bochao Lv ◽  
Yuan Lin
Keyword(s):  
Nervous System ◽  
Smooth Muscle ◽  
Inhibitory Effect ◽  
Intestinal Smooth Muscle ◽  
Low Doses ◽  
Contractile State ◽  
Myosin Phosphorylation ◽  
Bidirectional Regulation ◽  
The Central Nervous System ◽  
High Doses

Emodin is traditionally used as a laxative and is found to increase or decrease the contractility of intestinal smooth muscle in low doses and high doses, respectively. In this study, we propose that bidirectional regulation (BR) on the contractility of jejunal smooth muscle (CJSM) is inducible by emodin in the absence of control by the central nervous system. The results indicated that emodin-induced BR had the following characteristics. A stimulatory effect on CJSM was induced by emodin at 7 low contractile states, and an inhibitory effect was induced on CJSM at 7 high contractile states. Emodin-induced BR on myosin phosphorylation was also observed. BR was not observed in the presence of tetrodotoxin, suggesting that enteric nervous system is required for producing BR. The stimulatory effect of emodin on CJSM was abolished by atropine and diphenhydramine, respectively, suggesting that BR was correlated with cholinergic and histamine system while jejunal smooth muscle was at low contractile state. The inhibitory effect of emodin on CJSM was abolished by phentolamine, propranolol, and L-NG-nitroarginine (L-NNA), respectively, suggesting that BR was related to adrenergic hyperactivity and with a nitric oxide relaxing mechanism while jejunal smooth muscle was in a high contractile state. The exact mechanism, however, needs further investigation.

Measurements of osmotic permeability in the Malpighian tubules of an insect, Rhodnius prolixus Stål

1982 ◽  
Vol 216 (1204) ◽  
pp. 267-277 ◽  
Keyword(s):  
Ion Transport ◽  
Experimental Method ◽  
Malpighian Tubule ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Unstirred Layer ◽  
Osmotic Permeability

(i) With use of a novel experimental method, an improved estimate has been obtained for the value of the osmotic permeability ( P os ) of Rhodnius Malpighian tubules, 4.3 x 10 -3 cm s -1 osmol -1 l. Corrections for unstirred layer effects permit a further 35% increase in the value of P os , to 5.8 x 10 -3 cm s -1 osmol -1 l. (ii) In the lower Malpighian tubule, P os decreases from 3.4 x 10 -3 cm s -1 osmol -1 l at the junction with the upper Malpighian tubule to 0.4 x 10 -3 cm s -1 osmol -1 l at the junction with the gut. In lower tubules stimulated with 5-HT, P os is reduced over most of their length by about 50% . It is suggested that reduced values of P os in the lower portions of the lower tubule prevent water movements accompanying 5-HT-stimulated KCl resorption over the same area of the tubule. (iii) Values of P os in the upper segment of the upper tubule are discussedin relation to proposed mechanisms for coupling water movements to ion transport during isosmotic secretion by the tubule.

Fine Structure of the Malpighian Tubules of the Mosquito, Culex pipiens

1971 ◽  
Vol 29 ◽  
pp. 402-403
Author(s):  
Brendan Clifford
Keyword(s):  
Fine Structure ◽  
Culex Pipiens ◽  
Stellate Cell ◽  
Malpighian Tubule ◽  
Cell Types ◽  
Instar Larva ◽  
Malpighian Tubules ◽  
Calliphora Erythrocephala ◽  
Distinct Cell ◽  
Basal Plasma

An ultrastructural investigation of the Malpighian tubules of the fourth instar larva of Culex pipiens was undertaken as part of a continuing study of the fine structure of transport epithelia.Each of the five Malpighian tubules was found to be morphologically identical and regionally undifferentiated. Two distinct cell types, the primary and stellate, were found intermingled along the length of each tubule. The ultrastructure of the stellate cell was previously described in the Malpighian tubule of the blowfly, Calliphora erythrocephala by Berridge and Oschman.The basal plasma membrane of the primary cell is extremely irregular, giving rise to a complex interconnecting network of basal channels. The compartments of cytoplasm entrapped within this system of basal infoldings contain mitochondria, free ribosomes, and small amounts of rough endoplasmic reticulum. The mitochondria are distinctive in that the cristae run parallel to the long axis of the organelle.

ANTAGONISTIC ACTION OF NORETHYNODREL ON THE TESTOSTERONE-DEPENDENT PROCESS OF FRUCTOSE FORMATION IN MOUSE SEX ACCESSORY ORGANS

1966 ◽  
Vol 51 (2) ◽  
pp. 224-230 ◽  
Author(s):  
John A. Thomas ◽  
Edward T. Knych
Keyword(s):  
Antagonistic Activity ◽  
Low Doses ◽  
Antagonistic Action ◽  
Dependent Process ◽  
High Doses

ABSTRACT Norethynodrel antagonized the fructose stimulating effects of exogenous testosterone in sex accessory organs of castrate mice. It was antiandrogenic at both low doses (50 μg) and high doses (400 μg) of testosterone. Norethindrone and ethisterone suppressed fructose formation in the testosterone-treated castrate mouse, but not as effectively as norethynodrel. Norethandrolone exerted no antagonistic activity.

Some Aspects of the Psychopharmacological Activity of Maprotiline (Ludiomil®): Effects of Single and Repeated Treatments

1978 ◽  
Vol 6 (6) ◽  
pp. 421-429 ◽  
Author(s):  
A Delini-Stula ◽  
E Radeke ◽  
A Vassout
Keyword(s):  
Nervous System ◽  
Chronic Treatment ◽  
Conditioned Fear ◽  
Conditioned Avoidance ◽  
Repeated Treatment ◽  
Antidepressant Effects ◽  
The Central Nervous System ◽  
Pre Treatment ◽  
High Doses ◽  
Psychopharmacological Activity

Three different aspects of the psychopharmacological activity of the antidepressant maprotiline were investigated: its influence on serotoninergic functions the effects produced by chronic treatment its central nervous depressant and anxiolytic properties. Study of the effects of maprotiline on 5-HTP-induced head-twitch in mice pre-treated with pargyline or on hyperpyrexia in rats provided no evidence that the drug interferes with serotonin-mediated functions in the central nervous system even after quite high doses. These findings corroborate the results of extensive neurobiochemical investigations, which failed to demonstrate any influence of maprotiline on the metabolism of serotonin. Chronic studies showed that classical effects of maprotiline such as antagonism against reserpine-induced ptosis or tetrabenazine-induced catalepsy do not change in their intensity after daily administration of the drugs in a dose of 30 mg/kg p.o.for 11 days. A new component of the action of the compound, not detectable after one single dose, seems to appear, however, after repeated treatment (8 days). This effect is manifested in the restoration of conditioned avoidance behaviour after its suppression by pre-treatment with reserpine. The same effect is produced by imipramine. It is suggested that this restorative effect may be due to an additional activation of the dopaminergic nervous system and may have a bearing on the appearance of clinical antidepressant effects. Maprotiline was found to potentiate central nervous depressant effects of drugs like chlorpromazine, phenobarbitone and propranolol. This affords further confirmation that, in addition to its antidepressant qualities, it possesses sedative actions. An anxiolytic component was also demonstrated in rats in which maprotiline suppressed the conditioned, fear-induced rise in body-temperature.

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