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The endocrine control of Malpighian tubule secretion: past, present and future

100%

Coast G. M.

Pestycydy

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2008

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nr 1-2

87-94

Work by Ramsay in the 1950’s established the foundations for our current understanding of primary urine production by Malpighian tubules and we now have detailed knowledge of the epithelial transport processes underlying fluid secretion. Identified neuropeptides and biogenic amines have been shown to stimulate fluid secretion and, for some, detailed information is available on the second messenger pathways and transport processes they activate. There are significant gaps in our knowledge, however, particularly concerning the role of identified diuretics in vivo. The hormonal status of many has yet to be established and it is also unclear whether they are used to control different types of diuresis.

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Electrochemical gradients across Malpighian tubules of the house cricket, Acheta domesticus, and the mode of action of kinin and CRF-related diuretics

100%

Coast G. M.

Pestycydy

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2009

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nr 1-4

27-32

Double-barrelled ion-selective microelectrodes were used to measure Na+, K+ and Cl- activities in the principal cells of cricket Malpighian tubules, allowing electrochemical gradients across apical and basal membranes to be calculated. At the basal membrane, K+ and Cl- gradients support passive exit into the bathing medium. A thermodynamic analysis shows both ions can be taken up by Na+/K+/2Cl- cotransport driven by a favourable Na+ gradient. At the apical membrane, cations are actively transported into the lumen whereas Cl- moves passively. Evidence is presented to show that diuretic kinins open an apical membrane Cl- conductance whereas Achdo-DH acts via cAMP to stimulate the basal membrane NKCC.

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Aspects of the control of diuresis in the blood gorging insect, Rhodnius prolixus

80%

Orchard J., Donini A.

Pestycydy

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2008

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nr 1-2

61-66

Post-feeding diuresis in Rhodnius prolixus is neurohormonally controlled by serotonin and at least one peptidergic diuretic hormone (possibly a CRF-related peptide). These appear to be released by two different neurosecretory groups – 5 dorsal unpaired median (DUM) cells and 5-6 lateral neurosecretory cells of the mesothoracic ganglionic mass. The DUM cells co-localize serotonin and the calcitonin-related peptide RhoprDH31. The lateral neurosecretory cells co-localize a CRF-related peptide and a kinin-like peptide. Serotonin and the CRF-related peptide, ZooneDH, each stimulate maximum secretion by the upper Malpighian tubules, whereas only serotonin stimulates KCl reabsorption from the lower Malpighian tubules. RhoprDH31 is only weakly diuretic and Leucokinin 1 has no diuretic activity. Neither stimulates KCl reabsorption. The possible role for multiple diuretic hormones and for co-localization of diuretic factors is discussed.

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Evidence for a CAP2b-like anti-diuretic hormone in the blood-gorging insect, Rhodnius prolixus

80%

Paluzzi J.-P., Orchard I.

Pestycydy

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2005

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nr 3

141-145

Ograniczanie wyników

4 Pestycydy

2 Coast G. M.

1 Donini A.

1 Orchard I.

1 Orchard J.

1 Paluzzi J.-P.

1 2009

2 2008

1 2005

The endocrine control of Malpighian tubule secretion: past, present and future

Electrochemical gradients across Malpighian tubules of the house cricket, Acheta domesticus, and the mode of action of kinin and CRF-related diuretics

Aspects of the control of diuresis in the blood gorging insect, Rhodnius prolixus

Evidence for a CAP2b-like anti-diuretic hormone in the blood-gorging insect, Rhodnius prolixus